2006年度日本冷凍空調学会年次大会 講演題目「Particle Swarm Optimization の適用による単段型吸着冷凍機の最適設計」

平成10年度日本冷凍空調学会学術講演会 講演題目「LNG 冷熱を用いた多段動力回収システム —アンモニア・水混合媒体を用い たサイクルのエクセルギー評価—」

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：日本語  

記述言語：英語  

This paper presents theoretical and experimental investigation of an adsorption cooling system to predict the cycle performance of one bed adsorber based on the equilibrium condition. For this particular study, activated carbon-ethanol pair was chosen as the adsorbent-refrigerant pair because of a high adsorption capacity of activated carbons against ethanol. The experiment was conducted on five different pre-cooling and pre-heating settings. The experiments carried out were divided to two sections. First, the preliminary experiments were carried out on two extreme conditions. For the first extreme condition, the adsorption and desorption process were carried out without pre-cooling and pre-heating. Whilst for the second extreme condition, the adsorbent was pre-cooled and pre-heated until the adsorbent reach adsorption and desorption temperature. Then the experiments were carried out with three different time of pre-cooling/pre-heating time which was selected based on the preliminary experiments. The heat balance were analyzed critically and the optimum cycle time, namely the pre-cooling and pre-heating time for each adsorption and desorption process is discussed by identifying the suitable adsorbent pressure and temperature of the system.

DOI： 10.11322/tjsrae.15-26RE

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ijrefrig.2009.10.005

記述言語：英語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.applthermaleng.2009.01.005

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ijrefrig.2008.12.002

記述言語：英語  

記述言語：英語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.renene.2005.05.003

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.renene.2004.05.010

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/S0360-5442(00)00002-5

掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Energy  

Upgrading low-grade industrial waste heat to higher temperatures plays a crucial role in improving energy efficiency and advancing sustainable development. In this study, a comprehensive dynamic performance analysis of a dual-bed adsorption heat transformer (AHT) system driven by a large pressure jump is conducted to upgrade the low-grade waste heat. The AQSOA-Z05/water working pair is investigated under constant flow output (CFO) and constant temperature output (CTO) modes. The theoretical maximum temperature lift potential governing adsorbent selection and operating conditions is thoroughly explored. Compared to the CFO mode, the CTO mode is found to provide more stable and controllable high-temperature output suitable for practical applications while achieving a higher specific heating power. Further, key parameters influencing system performance, such as adsorption connecting pipe diameter, target temperature lift, ambient and waste heat temperatures, are systematically analyzed under the CTO mode. Ambient temperatures of 0–30 °C facilitate stable operation, whereas waste heat below 70 °C leads to performance deterioration. To bridge the variable flow output under the CTO mode with heat load demands, integrating a heat storage tank and control system is suggested. The insights provided are expected to furnish valuable guidelines for the design and optimization of the AHT system, thereby facilitating more effective utilization of waste heat and contributing to sustainable industrial practices.

DOI： 10.1016/j.apenergy.2024.124478

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出版者・発行元：Applied Thermal Engineering  

The surging demand for air conditioning, especially in hot climates, underscores the urgency of strategies aimed at curbing fossil fuel reliance and fostering energy saving strategy. Despite the longstanding utility and advantages of the conventional mechanical vapor compression refrigeration system, sustainability hurdles persist owing to its pronounced electricity demand. While evaporative cooling, harnessing water evaporation, emerges as a more efficient alternative, its efficacy is contingent upon environmental conditions. Addressing this, dew-point evaporative cooling (DPEC) presents an innovative direction, showcasing superior efficiency by directing supply air into a wet channel. This study delves into the thermodynamic losses within a counter-flow configured DPEC system, employing a transient entropy generation model rooted in the second law of thermodynamics to provide a comprehensive analysis of DPEC's performance. Key findings that emerged from this study reveal that (1) the transient entropy generation is intricately distributed across different layers of the dew point evaporative cooling (DPEC) system, including dry air, wet air, the channel plate, and the water film; (2) Parametric analyses highlight the significant impact of factors on entropy generation, inlet air temperature has a minimal effect on system efficiency, but higher temperatures increase thermal losses. Excessive humidity limits evaporative potential, while low humidity significantly increases entropy generation. The system performs optimally at a working ratio of 0.3 and lower air velocities (within the inlet air velocity range of 0.6 to 2.2 m/s). Channel length has little impact, while the system is more sensitive to channel height, with a height of 2.5–3.5 mm being conducive to better performance. Experimental validation demonstrates the model's accuracy in predicting system performance. The research contributes to a deeper understanding of DPEC systems, offering insights for achieving optimal operating conditions and enhancing overall efficiency in the pursuit of sustainable development.

DOI： 10.1016/j.applthermaleng.2024.124443

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出版者・発行元：Journal of Porous Materials  

This study not only explores the fabrication of rare zeolites from waste pumice and examines the impact of aging on their porosity and adsorbate uptake but also provides practical insights for waste management and agricultural applications. The use of organic templates was avoided in the synthesis due to their high cost and pollution associated with their calcination. Potassium-exchanged gonnardite (K-Gon) and perlialite were hydrothermally synthesized using KOH. Interestingly, we found that increasing the magnetic stirring duration during synthesis had a significant impact on the products’ surface area and pore volume, leading to an increase from 39 m²/g to 182 m²/g and from 0.11 cm³/g to 0.30 cm³/g, respectively. This improvement resulted in an increased adsorbate uptake at higher pressures. At shorter stirring times, potassium-exchanged gonnardite zeolite with tetragonal symmetry was the most prevalent phase, which differs from the orthorhombic symmetry of Na-rich gonnardites. Additionally, we observed that the product content of perlialite (hexagonal symmetry) increased with longer stirring durations while K+ ions decreased. This suggests that increased stirring time can increase the disorderliness of extra framework particles, as seen in perlialite, as opposed to K-Gon. Longer stirring time produces other zeolites with slightly less K but improved textural properties, which can potentially accommodate more water. It is also useful for agricultural purposes, such as keeping soils moist and decontaminated, and as adsorbents for greenhouses’ air conditioning.

DOI： 10.1007/s10934-024-01663-z

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出版者・発行元：Advanced Powder Technology  

This research reports conventionally-synthesized-zeolites with comparatively large surface area (SSA) and water-uptake prepared solely from waste-pumice. Notably, the synthesis process avoided using additional commercial raw materials, organic templates, and high temperatures, so that the process was less costly and ecofriendly. To optimize the process, the synthesis time was varied, and the mixture of the raw material and alkaline solution was stirred for 12 h. The zeolite mother liquor was also recycled. Water adsorption experiments were carried out using gravimetric measurements. The Na-P1-rich zeolite product with an optimal water uptake of 0.256 g/g was synthesized after 48 h of hydrothermal activation (H). On the other hand, the product's optimal SSA of 186 m2/g was achieved after 36H under similar conditions (rich in faujasite). Adsorption isotherms showed that water uptake increased with activation time and with the inclusion of mother liquor recycling. Furthermore, recycling resulted in a product with enhanced SSA compared to its precursor. Un-recycled products exhibited relatively high-water uptake both at low and high relative-pressure, while the recycled product had a high uptake at high relative pressure. All products could be used in adsorption heat pump (AHP) applications (air conditioning) suited for high relative humidity (RH) environments. However, high-synthesis-time non-recycled products could also work for low RH AHP applications.

DOI： 10.1016/j.apt.2024.104713

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出版者・発行元：Journal of Materials Science  

Air-conditioning (A/C) systems in tropical regions are characterized by significant energy consumption for latent load handling. Decoupling of the latent load from the A/C units can be achieved using a dedicated dehumidification system while the A/C systems handle only the sensible heat at high efficiencies. Desiccants are widely used in industry, and adsorbent materials that exhibit a unique isotherm shape, i.e. "S shape", have been developed extensively. Recently, activated carbons (ACs) have been discussed as effective adsorbents for dehumidification applications. Although pristine ACs are considered to be hydrophobic materials, certain surface treatments initiate surface phenomena that promote water vapour uptake at relative pressures above 0.4 due to microdroplet aggregation. This work reviews and reports the latest developments of sustainable activated carbons for dehumidification using a multiscale approach spanning from the sustainable precursor selection, “green” activation processes and surface functionalization, adsorption thermodynamics, and system-level developments. With the focus on sustainability, we demonstrate that water adsorption and viable adsorption range are gradually improving with the progressing research, and they are reaching operational values required for practical use. The unique adsorption process of water onto ACs is further explained in detail using solvation theory on the microdomains created by the hydrophilic functional groups while providing clarification of thermodynamic properties adopting the specificities of water/activated carbon adsorption pair. The predicted performance of a desiccant dehumidification system utilizing activated carbon is evaluated using the local weather conditions of numerous major cities worldwide. The highest dehumidification performances of activated carbon, as indicated by the unified SDP (specific dehumidification power) value, are reached particularly in cities that suffer from high humidity and temperature the most proving the viability of this cheap and sustainable material. Graphical abstract: (Figure presented.)

DOI： 10.1007/s10853-024-10265-8

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出版者・発行元：AIP Conference Proceedings  

Adsorption thermal energy storage (aTES) is one of the possible technologies that could help to eliminate our dependence on fossil fuels. The advantages of the adsorption systems lie in the possibility to supply hot as well as cold, and the fact that the aTES systems have negligible energy losses over time and therefore are also suitable for seasonal storage. Selection of the right adsorption pair to store the maximum amount of energy is then the key factor for high-efficiency system. In this work, we introduce the basic principles of the adsorption thermal energy storage and analyze the pivotal aspects for the high-performance adsorption thermal energy storage, not too dissimilar from the adsorption heat pumps. The adsorbate of choice for the storage applications remains water with the highest energy density coming from high enthalpy of vaporization and high polarity of the water molecules. Modern high-yield adsorbents for adsorption thermal energy storage are nearly without any exception tailored microporous materials with high water affinity such as microporous silica, zeolites and zeolite like materials and metal organic frameworks (MOFs).

DOI： 10.1063/5.0228013

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出版者・発行元：AIP Conference Proceedings  

In this simulation, convection heat transfer, friction factor, and flowing TiO2/water nanofluids inside the double tube concentric heat exchanger for both plain and insert twisted tape insert was approached by the numerical estimation using fluent Ansys software. The numerical were carried out in the Reynolds number range from 5000 to 10,000, the particle concentrations used 0.1%, and twisted tape insert with a ratio of 7 was used. As the Reynolds number rises, the nanofluid Nusselt number increases as well. The findings demonstrated that, compared to a simple tube heat exchanger, the twisted tube heat exchanger showed increased heat transfer, and the addition of nanofluid TiO2/water can increase the Nusselt number.

DOI： 10.1063/5.0228360

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出版者・発行元：International Journal of Heat and Mass Transfer  

In adsorption processes, gaseous molecules are trapped on the surfaces of the solid adsorbent because of the surface forces. In contrast to bulk liquid or gaseous phases, fluids in adsorbed phase display distinctive characteristics. Understanding of the adsorbed phase and developing accurate models for its thermodynamic properties are crucial in assessing adsorption processes. Most existing models for the adsorbed phase often portend thermodynamic inconsistencies since they invoked numerous assumptions (e.g., ideal gas behavior of the adsorbate and negligible adsorbed phase's specific volume). We thoroughly propose and examine thermodynamically consistent models for adsorbed phase thermodynamics (specific heat, enthalpy, and entropy). A new specific heat capacity expression is derived accounting for the typically neglected adsorbed phase specific volume. Adsorbed phase properties calculated using these new models exhibit behaviors closer to the liquid phase compared to the gaseous phase. In contrast, enthalpy and entropy of the adsorbed phase calculated using the models available in the literature have been found exceeding the corresponding gaseous phase boundaries at higher pressure/coverage. The proposed correlations are applied to the thermodynamic characterization of a newly developed adsorbent material, activated carbon MSF-A30M with ethanol adsorbate, and compared against other activated carbons reported in the literature. The comparison shows consistent values of thermodynamic properties, well within the theoretical boundaries. As a practical application of the new correlations, we applied them to evaluate the performance of the adsorption heat pumps using 30 different working pairs. Accurate evaluations of the entropy, which is a thermodynamic state property, will lead to improved entropy generation calculations using the classical thermodynamic approach. This work will significantly contribute to improved tracking of thermodynamic losses in adsorption processes, from low coverage to near saturation pressures (details on thermodynamics loss evaluations of the cycles not covered in the present work).

DOI： 10.1016/j.ijheatmasstransfer.2024.125579

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出版者・発行元：International Journal of Energy Production and Management  

The investigation of the substantial impact of natural gas composition on the parameters for operation as well as the performance of centrifugal gas compressors in gas turbine power plants is presented in this paper. The efficiency and dependability of these compressors are greatly impacted by the composition of natural gas, which is defined by the different proportions of methane, ethane, propane, butane, nitrogen, carbon dioxide, and other trace elements. This paper attempts to outline the complex effects of different gas compositions on compressor efficiency, maintenance needs, and overall plant operations through a thorough examination. Important factors to consider include how compressor longevity and performance are affected by gas density, energy content, corrosive components, moisture content, inert gases, and combustion characteristics. In addition, the study examines mitigating tactics to deal with issues brought on by variations in gas composition, including material compatibility, adaptive technologies, monitoring systems, and maintenance plans. This study offers insightful information that is crucial for maximizing the dependability and efficiency of centrifugal gas compressors in gas turbine power plants under various natural gas compositions.

DOI： 10.18280/ijepm.090307

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記述言語：英語   出版者・発行元：iScience  

Understanding changes in thermodynamic and transport properties during adsorption is crucial for the thermal management of metal-organic frameworks, which also imposes significant challenges for improved performance and energy density of adsorption system. Because of phase transitions in the intermolecular interactions involved in the adsorption phenomena, transport properties including the thermal conductivity exhibit interesting behaviors, yet fully understood. This study employs detailed molecular dynamics simulations to replicate the methane/Cu-BTC adsorption phenomenon for the evaluation of their thermal conductivities across different pressures and temperatures. The molecular simulations show that the thermal conductivities of both the adsorbent (Cu-BTC) and adsorbate (methane, adsorbed phase) vary notably during adsorption processes. Using the concepts of the change in the degree of free movements of the adsorbate molecules and atomic vibration of adsorbent, the reduction of the adsorbate thermal conductivity (∼70–93%) and increase thermal conductivity of the adsorbent (up to 3 times) in Cu-BTC+CH4 pair are explained.

DOI： 10.1016/j.isci.2024.110449

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PubMed

出版者・発行元：Thermal Science and Engineering Progress  

Light trapping is a popular method used to improve the performance of photothermal absorbers. Granular structures are one of the light-trapping structures currently developed. In this paper, a review on the working principle and types of granular structures is presented. Furthermore, recent findings pertaining to the innovations of granular structures as photothermal absorber materials are discussed. This paper presents the extent of research and development in this area and identify the potential of granular structures as photothermal absorbers. The performance metrics used to evaluate the performance of photothermal absorber materials are described, which will be useful as a reference for making valid and reliable measurements. Moreover, this paper presents the material properties, types of fluid flow, and energy loss management that need to be considered when analyzing the performance of photothermal absorbers, which will serve as a reference for scientists and engineers for future sustainable technology development.

DOI： 10.1016/j.tsep.2024.102689

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掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Heat and Mass Transfer  

Adsorption heat transformer (AHT) cycle is capable of upgrading the low-grade waste heat to a higher temperature. The maximum temperature lift of the AHT cycle can represent its theoretical performance limit. However, such a metric is currently absent from the literature due to the scarcity of fundamental studies on the heat upgrading sorption cycles. Therefore, in the present study, three models are proposed to derive the ‘maximum temperature lift’ of a typical AHT cycle: (i) heat engine heat pump representation, (ii) the 2nd law of thermodynamic formulation, and (iii) complete preheating. The first two models are developed based on the reversible cycle approach, whereas the 3rd model incorporates adsorbed phase properties. Thus, the first two models might be considered as the formulations for the thermodynamic temperature limit (lift) of an AHT cycle while the 3rd model is specific to the nature of a particular adsorbent + adsorbate pair which might be close to practical applications. The reversible models predict a maximum temperature lift of 22 ∘C to 58 ∘C for heat source temperatures between 50 ∘C to 80 ∘C. The 3rd model exhibits lower values of maximum temperature lift compared to the reversible models, owing to the inclusion of material properties in its formulation. The performance of the models is demonstrated by determining the maximum temperature lift of four water-based adsorption working pairs, each featuring distinct IUPAC (International Union of Pure and Applied Chemistry) isotherm types. This study will help propel the working pair selection and the thermodynamic modeling of sorption cycles to achieve its near maximum capability.

DOI： 10.1016/j.ijheatmasstransfer.2024.125384

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出版者・発行元：Evergreen  

This article preprocesses environmental information and use it as input for the Proximal Policy Optimization (PPO) algorithm. The algorithm is directly trained on a model vehicle in a real environment, allowing it to control the distance between the vehicle and surrounding objects. The training converges after approximately 200 episodes, demonstrating the PPO algorithm's ability to tolerate uncertainty, noise, and interference in a real training environment to some extent. Furthermore, tests of the trained model in different scenarios reveal that even when the input information is processed and does not provide a comprehensive view of the environment, the PPO algorithm can still effectively achieve control objectives and accomplish challenging tasks.

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記述言語：英語   出版者・発行元：九州大学グリーンテクノロジー研究教育センター  

Domestic heat pump is regarded as the most important contributor to greenhouse gas (GHG) emissions from buildings. R410A has been one of the most popular refrigerants in the heat pump system because of its eXcellent thermodynamic performance with near azeotropic nature. HoweVer, R410A greatly impacts climate with its global warming potential (GWP) which is eValuated as 2088 CO2-equiValent. Thus, this research purpose is to inVestigate refrigerant blends with a low GWP to replace R410A in domestic refrigeration applications. A screening of blends is carried out among the list of 5 low-GWP refrigerants, including R451A, R454A, R454C, R455A, and R459B, which are mainly combined by R32, R1234yf, R1234ze(E), and Carbon DioXide. The selection is based on the target GWPs (lower than 300), and the coefficient of performances (COPs) are analyzed on a single-stage heat pump cycle model by Python. The results present that the Volumetric capacities of low-GWP refrigerants are all lower than R410A, but their COPs are higher eXcept for R455A. R454A is considered the most accessible alternatiVe to R410A while its COP is 2% higher than R410A with the largest Volumetric capacity among low-GWP refrigerants. The climate impacts of these low-GWP refrigerants are also studied by the Life Cycle Climate Performance, which shows 22%~25% lower than the emissions of R410A. This research might supply a clue for the deVelopment of these new refrigerants to replace R410A.

DOI： 10.5109/7183465

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CiNii Research

掲載種別：研究論文（学術雑誌）   出版者・発行元：Energy Advances  

Hydrogen gas is among the sustainable energy forms that counteract the energy crisis. Polymer electrolyte membranes (PEMs) derived from biomass fillers and polyvinyl-based matrix blends have been fabricated and applied in H2 generation through electrolysis. Faradaic efficiencies ranging from 82.8 ± 1.9% to 88.9 ± 1.6% were exhibited when voltages of 6.5 V, 8 V and 10 V were applied; thus, proton conduction and hence H2 generation commenced at 2-2.5 V. The apparent morphology of the PEMs that verified the incorporation of pine bark (PB) and Chinese Tallow Seed Capsule (CT) fillers was visible as surface bumps and internal cavities within the PEMs. Although the proton conductivity of Nafion™ 115's (NF-M) was 23.94 mS cm−1, those of the fabricated PEMs (PB-M, CT-M and SSA-M) were 1.33, 0.46 and 0.48 mS cm−1, respectively. The PB-M exhibited good characteristics, including functional groups and water adsorption; thus, H2 production was achieved, but losses such as bubble production affected efficiency. This study presents a cost-effective alternative for H2 production that can be used in diverse applications.

DOI： 10.1039/d3ya00503h

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出版者・発行元：Journal of Engineering for Sustainable Buildings and Cities  

A comfortable indoor working circumstance can be accomplished by a ventilation and air conditioning system. There are several factors influencing the quality of indoor air, with the insufficiency of ventilation accounting for over 50% of the overall considerations. While traditional air conditioner is able to fulfill the needs of ventilation and indoor temperature control, low-efficiency and high energy consumption no longer align with the current sustainable and energy-efficiency goals. Thus, the development of energy-saving and high-efficiency air conditioning systems is crucial for realizing green and efficient building practices. Evaporative cooling technology, specifically dew-point evaporative cooling, has garnered extensive attention as an efficient cooling method and a candidate for environmentally friendly and high-performance alternatives to traditional air conditioning systems. This article investigates the thermodynamic losses involved in a dew-point evaporative cooling system using the counter-flow design. Detailed mathematical models for the evaporative cooler along with the entropy generation in the channels are developed. The model facilitates calculations of (1) the entropy generation distribution in different layers within the system and (2) the entropy generation of each layer and the whole system under various input conditions. Approaching the system from the second law of thermodynamics perspective, this model serves as a guide for selecting the optimal operating conditions, thus promoting the widespread application and commercialization of dew-point evaporative cooling systems with the counter-flow structure.

DOI： 10.1115/1.4065740

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Energy  

Open adsorption process of gas mixtures involves complex heat and mass transfer mechanisms. Understanding of the physical mechanisms and their impacts on the adsorption process from gas mixtures is vital. In this study, a detailed analysis of an open CO2 adsorption from CO2/N2 mixtures using zeolite 13X-APG was investigated. Key physical mechanisms (unsteady, diffusive, convective, and component source, etc.) involved were scrutinized, and their order of magnitudes relative to the system energy complex were determined. The influences of these physical mechanisms on the equilibrium and dynamic nature throughout the capture were quantified. The validated computational fluid dynamics (CFD) simulations for the same adsorption domain were carried out to verify the rationality of the scaling method. The adsorption time, tad; the maximum average temperature, T‾max; CO2 removal rate, Rre,CO2; equilibrium pressure drop, ΔPeq on different scale parameters and their sensitivity were investigated. The maximum relative sensitivity to porosity was found to be −0.945, 0.0235, −0.357, and −5.33 for tad, T‾max, Rre,CO2 and ΔPeq, respectively. It is observed that heat transfer by the conduction mechanism inside the bed significantly influences all scale parameters, except for ΔPeq. This work will contribute to a better understanding of the atmospheric CO2 adsorption and provide guidance for the design optimization.

DOI： 10.1016/j.energy.2024.130805

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掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Refrigeration  

This study presents a comparative energy, exergy, and life cycle climate performance (LCCP) analysis of various refrigerants in a cascade refrigeration system (CRS). The refrigerants analyzed in the low-temperature cycle (LTC) include R-23, R-116, R-41, R-170, R-1150, and R-1132a whereas high-temperature cycle (HTC) utilizes R-404A, R-455A, R-454C, R-459B, R-161, R-290, R-1270, and R-1234yf. For the first time for CRS, LCCP analysis is conducted and fourth generation low GWP and less flammable prospective refrigerants R-1132a, R-455A, R-454C, R-459B are analyzed. The study aims to find a refrigerant pair that outperforms R-23/R-404A in terms of thermodynamic efficiency while also considering environmental impact and safety considerations. Among the 48 refrigerant groups analyzed, the study reveals that R-170/R-161 and R-41/R-161 demonstrate superior performance in terms of thermodynamic efficiency and environmental impact assessment whereas the largest exergy destruction components are HTC/LTC compressors. However, if flammability is a major concern, the recommended refrigerant pair is R-1132a/R-1234yf, as it is a suitable alternative in terms of safety considerations while still maintaining favorable thermodynamic and environmental performance.

DOI： 10.1016/j.ijrefrig.2023.12.020

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Colloids and Surfaces A: Physicochemical and Engineering Aspects  

Carbon capture, storage, and utilization from post-combustion processes using adsorption phenomena has emerged as a promising solution to the greenhouse gas emission crisis. The capacity of solid porous adsorbents dictates the performance of such carbon capture processes. Developments of porous adsorbents with favourable structural and chemical characteristics of the pore have been a major research area. Computational tools, notably the Grand Canonical Monte Carlo (GCMC) simulation, are widely employed to characterize the adsorption process in crystalline adsorbents like metal-organic frameworks and zeolites. Activated carbons are becoming promising alternatives to conventionally-used zeolite adsorbents for CO2 adsorption, because of their abundant microporosity and cost performance. However, the amorphous nature of the activated carbon materials poses a challenge in accurately modelling their pore characteristics and their adsorption process. Therefore, this study systematically explores the effect of pore size distribution and type of functional groups on the adsorption of CO2 on activated carbons using a simplified slit-pore graphite structure representing the activated carbon adsorbent. Four different pore sizes (7 Å, 8.9 Å, 18.5 Å, and 27.9 Å) and three oxygen-containing functional groups (Carbonyl, Hydroxyl, and Carboxyl) were selected to model the graphite structures. Results from the GCMC simulation reveal a significant rise in the CO2 adsorption capacity (from 4 mmol/g to 21 mmol/g) as the pore size was increased from 7 Å to 27.9 Å. Likewise, the functional groups enhance the low-pressure adsorption process by reducing the onset pressure of the pore filling by a factor of 100, especially in ultra-micropores. Likewise, we demonstrate the increase in the isosteric heat of adsorption due to the reduction in the pore size and the presence of functional groups. Additionally, the study illustrates the adsorbed phase behaviour of CO2 concerning the pore characteristics, a facet often overlooked in the existing literature. The adsorbed phase local density and molecular orientation distribution are analysed to understand the variation in the adsorption uptake and isosteric heat of adsorption properties. The study further identifies the adsorbed phase monolayer to multilayer transition and the ‘T′-shaped orientation of the adsorbed CO2 molecules as the key contributors to the high isosteric heat of adsorption in 8.9 Å pore size. It is envisaged that this study will navigate the precision adsorbent development for an efficient carbon capture process.

DOI： 10.1016/j.colsurfa.2023.133113

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出版者・発行元：International Journal of Energy Production and Management  

The global shift towards renewable energy sources is driven by the desire for a sustainable energy future. Integrating intermittent renewable sources and maintaining grid stability are obstacles that must be overcome to achieve this goal, which is why grid stability and energy storage systems are being investigated in this study using Energy PLAN simulation. This study conducts a thorough analysis of energy storage solutions necessary to support Japan's energy landscape shift to renewable electricity. It offers a comprehensive analysis considering technological, environmental, and policy aspects to evaluate the applicability, difficulties, and potential of renewable electricity. Technical factors emphasize how critical it is to maintain grid balance and consider scalability and technology compatibility with Japan's distinct energy infrastructure. Economic analyses examine revenue streams, levelized storage prices, investment needs, and cost-benefit evaluations to shed light on the viability and appeal of technologies for storing energy from an economic standpoint. The goal of synthesizing these several characteristics is to provide policymakers, and energy stakeholders participating in Japan's ambitious journey towards renewable electricity with strategic insights, practical recommendations, and a roadmap. This study aims to steer Japan's energy landscape towards resilience, sustainability, and diversification by establishing links between imperatives, economic feasibility, and technical breakthroughs.

DOI： 10.18280/ijepm.090105

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掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Heat and Mass Transfer  

In the present study, the adsorption isotherms of difluoromethane (R32) on the activated carbon (MSC 30) throughout a temperature range of 25 °C to 150 °C and pressures up to 3000 kPa are measured for possible application in adsorption cooling systems. The Dubinin-Astakhov model was used to fit the experimental data. A thermodynamic model is proposed in this study to investigate the adsorption potential under supercritical conditions. The model is validated using the isotherm data from the experiments and literatures for different working pairs. The validation results exhibited a good agreement between the proposed model and the experimental data, signifying the precision and dependability of the model. The corresponding adsorption isosteric heat model was derived and verified, taking into account both the inclusion and exclusion of the adsorbed volume correction. Furthermore, the developed models were utilized in the equilibrium analysis of an adsorption heat pump to evaluate the performance of the system in terms of the theoretical coefficient of performance (COP) and specific cooling energy (SCE). The analysis covered the driving heat source temperature ranging from 30 °C to 150 °C, with different evaporation temperatures and adsorption temperatures. The results showed that the maximum COP value of 0.47 for the adsorption heat pump system employing the MSC30+R32 pair was achieved at a desorption temperature of 115 °C, at which the SCE was 315.5 kJ·kg−1. The results can potentially improve the accuracy of predicting adsorption behavior and contribute to the development of more efficient and effective adsorption systems.

DOI： 10.1016/j.ijheatmasstransfer.2023.124873

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Powder Technology  

Activated carbon, due to its notable porosity and cost-effectiveness, emerges as a promising desiccant material. This research delves into the utilization of pinecones as a precursor for the production of activated carbon through steam activation. The resultant activated carbon samples presented a porous structure and exhibited a high water adsorption capacity, with the highest adsorption capacity reaching 0.35 kg/kg, placing it in competition with commercial silica gel. Various experimental parameters were systematically manipulated during the production process to optimize both the pore structure and water adsorption capacity of the activated carbon samples. Elevating the carbonization temperature from 700 °C to 900 °C proved effective in enhancing pore distribution and elevating water adsorption capacity. Furthermore, higher activation temperatures contributed to the formation of additional mesopores and macropores, possibly attributable to micropore enlargement through steam activation. Nevertheless, these elevated activation temperatures resulted in an undesired increment in mesopores concerning water adsorption. The extension of activation time led to increased micropore formation, albeit with concurrent disruption, culminating in heightened total pore volume and surface area. This extension shifted the water adsorption-desorption isotherm to higher relative pressure ranges, accompanied by a larger hysteresis loop. Moreover, an increased steam mass flow rate was found to enhance the pore structure and water adsorption capacity of the activated carbon. The activated carbons exhibited sigmoid-shaped isotherms, signifying their suitability for both open-cycle and closed-cycle adsorption systems.

DOI： 10.1016/j.powtec.2023.119084

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Thermal Engineering  

Solar energy is an important energy source for a sustainable future. The advancements of solar cells for electricity production require improvements in the cooling technology. Conventional air cooling is not able to cool the photovoltaic (PV) panels effectively. On the other hand, dew-point evaporative cooling (DPEC) can bring down the inlet air temperature below its wet bulb which makes itself an excellent candidate for PV cooling. In this work, a novel cooling configuration that consists of two wet channels: one in the cooler (conventional DPEC) to produce the pre-cooled supply air and the other at the back of the PV panel, was proposed. A physics-based mathematical model utilizing local weather conditions was developed for the system to investigate its transient performance. The cooling performance and subsequent improvement in the PV's energy efficiency of the proposed system were compared with a traditional DPEC-based cooling approach. It was observed that the proposed system can maintain an efficiency of more than 15% (with 16.7% maximum) under two environmental conditions in summer, which is an increase of 16.4% compared to air cooling. The proposed PV cooling method will help to improve the overall performance of the solar PV systems and increase renewable energy utilizations.

DOI： 10.1016/j.applthermaleng.2023.121695

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Engineering Science  

The development of cost-effective and environmentally friendly solar thermal technologies that deliver high performance poses several challenges, where the collector and absorber components play a pivotal role. This research addresses these issues by investigating enhanced temperature generation using a 30 cm × 30 cm Fresnel lens collector under solar illumination from a xenon lamp. Natural stone materials (andesite, coal, and pumice), characterized by granular structures with an average diameter of 1.68–2.00 mm, were selected because of their abundance and eco-friendliness. This research is focused on evaluating the effect of Fresnel lens on temperature generation performance. Two types of temperature generation tests were carried out: wet tests (where the natural stone materials were immersed in distilled water) and dry tests (where the natural stone materials were used in dry conditions). The morphologies of the natural stone materials were examined using an optical microscope and scanning electron microscope. Furthermore, the optical properties of the natural stone materials were analyzed using an ultraviolet–visible (UV–VIS) spectrophotometer. The findings revealed that there were significant improvements in the photothermal absorber performance with the use of a Fresnel lens in dry tests, where the highest temperature was achieved for coal (103.25 °C), followed by andesite (89.00 °C) and pumice (73.00 °C). The impurities varied between the materials, where the impurities were most dominant for pumice while coal was more uniform. Further examination using scanning electron microscope showed that all materials had light-trapping structures in the form of rough surfaces, pores, and crack gaps. Andesite was dominated by rough surfaces, while coal and pumice were dominated by crack gaps and pores, respectively. However, based on the UV–VIS spectrophotometric results, there were no correlations between the optical properties (absorbance, reflectance, and transmittance) and temperature achieved by the photothermal absorber materials. This research demonstrates the potential of using natural stone materials as photothermal absorbers in combination with a Fresnel lens collector for low-to-medium temperature solar thermal applications.

DOI： 10.5937/jaes0-47834

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記述言語：日本語   出版者・発行元：公益社団法人 日本冷凍空調学会  

<p>本研究で吸着材に使用した粉末状活性炭(MSC-30)は，吸着材としてよく使われてきたシリカゲルより比表面積が大きく，さらに大きな吸着量が得られると期待される．吸着質には地球温暖化への影響が非常に小さい低GWP 冷媒のR 1233zd(E)を使用し，その吸着特性を同じ低GWP 冷媒のR 1234yf と比較した．本研究の結果から，単位質量あたりの吸着量および平衡状態に至るまでの吸着速度ともにR 1233zd(E) がより優れた結果を示した．なお，吸着相における体積変化を理論的に考慮したモデルで吸着熱を予測した結果，ほぼ同程度であった．吸着特性に関するこれらの基本情報は，機能性活性炭をフロン類の回収，分離，再生に活用するための基礎情報として高い有効性を有する．</p>

DOI： 10.11322/tjsrae.23-25_oa

CiNii Research

出版者・発行元：Proceedings of the Thermal and Fluids Engineering Summer Conference  

Ultralow-temperature (ULT) refrigeration is essential for various applications, including food, pharmaceutical, and cryogenic processes, where stringent temperature control is required. However, the energy intensity and the use of high-GWP refrigerants in these systems contribute to global warming and climate change. R23 and later R23 mixtures, like R508b, have been considered as zero ozone-depleting potential refrigerants, but their excessive global warming potential has always been a topic of concern. The theoretical replacements are multi-refrigerant multi-cascade cycles which are not efficient or economical enough to be accepted by manufacturers. R1150, R744a and R170 are considered as an environmentally friendly refrigerants to replace R23 family. However, their infra-room critical temperature makes them suitable only in bottoming cycles of cascade systems. This project presents an innovative approach to the single-refrigerant ULT refrigeration cycle. An optimized four-stage flash intercooling turboexpander cycle was designed and thermodynamically analyzed. COP around 0.5 is achievable, even though the cycle has a temperature lift of 140°C and an approximate compression ratio (CR) of 100. Pressure optimization caused the compressors to achieve isentropic efficiency ranging from 0.6 to 0.7, with compression ratios between 2.5 and 4. Different refrigerants and operating conditions were simulated under realistic assumptions and the positive impact of using turboexpanders on performance was confirmed.

DOI： 10.1615/TFEC2024.hpu.050699

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出版者・発行元：Lecture Notes in Mechanical Engineering  

The collector and absorberAbsorber are the two main components most influential in obtaining high solarSolar thermal performance. This study used a 30 × 30 cm Fresnel lens under a xenon lamp to improve the temperature generation performance. The materials photothermal absorbersAbsorber used are coal, andesite, and pumice, with an average granular structure diameter of 1.68–2 mm. This study aims to examine the effect of Fresnel lenses on the temperature generation performance of natural materials with granular as light trap structures and investigate which materials have the best performance. This study used an experimental method with dry and wet conditions in distilled water (H2O). The results show that the use of Fresnel lenses improves temperature generation performance. The best materials sequence in wet conditions are andesite, coal, and pumice. While in dry conditions are coal, andesite, and pumice. The heat generated has the potential to be applied to low and medium-temperature solarSolar thermal technology.

DOI： 10.1007/978-981-97-0106-3_50

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出版者・発行元：AIMS Energy  

The concerns over greenhouse gas emissions, environmental impacts, climate change, and sustainability continue to grow. As a result of countermeasures, many modern gas turbine power plants and combined cycle power plants are considering to use hydrogen as a clean fuel alternative to fossil fuels in the power plant industry. We assessed the implications of such transition from natural gas to hydrogen as fuel in a gas turbine power plant’s balance of plant (BOP) equipment. Using the DWSIM process simulation software and the methodology of compression power changes against different gas compositions, the impact of blending hydrogen with natural gas on temperature differentials, energy consumption, adiabatic efficiency, compression power, and economic implications in gas turbine power plants were examined in this paper. We discovered, through analysis, that there was not a noticeable boost in compression power or energy consumption when 50% hydrogen and 50% natural gas were blended. Similarly, there was no discernible difference in temperature differentials or adiabatic efficiency when 30% hydrogen and 70% natural gas were blended. Moreover, mixing 50% hydrogen and 50% natural gas did not result in a noticeable cost climb. In addition, the techno-economic analysis presented in this paper offered valuable insights for power plant engineers, power generation companies, investors in energy sectors, and policymakers, highlighting the nature of the fuel shift and its implications on the economy and technology.

DOI： 10.3934/energy.2024021

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：E3S Web of Conferences  

Using green biofilters can help eliminate air pollutants and improve urban air quality. In the current study, Prunus × Yedoensis capacity of phytoremediation was investigated as a bio filter of Particulate matter (PM) in spring and summer seasons in Japan. Two samples were analysed to extract three fractions of PM (coarse, fine and ultra-fine). Results showed lower deposition of PM in spring season with total of 20.2 μg.cm-2 and high proportion for fine fraction (2.5-10μm), comparing with summer season which showed a higher deposition of PM with total of 31.9 μg.cm-2. Ultra-fine fraction (0.2–2.5μm) recorded the highest values with a percentage of 23.9% of the total PM deposition. Leaf micromorphological characteristics such as, rough surface and serrated margin can enhance the Prunus × Yedoensis ability of particulate matter accretion. This study confirms that vegetation has an efficient role in improving the quality of urban air. Further structural analysis should be included to deepen the understanding of phytoremediation phenomena in plants.

DOI： 10.1051/e3sconf/202346502030

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：E3S Web of Conferences  

The Power-to-Gas (PTG) is one of the progressing technologies that enables the conversion of electrical energy into hydrogen or methane gas. This study focuses on the comprehensive analysis of energy efficiency, exergy efficiency, and exergy destruction rate within the PTG overall system. The investigation covers the evaluation of the wind turbine for power generation, the proton exchange membrane (PEM) employed in hydrogen production, and the methanation unit dedicated to methane production. The analysis examines the overall system as well as each individual component. By quantifying the energy and exergy efficiencies, this study provides potential improvements for maximizing the PTG system's overall effectiveness. The outcomes of this study contribute to the advancement and deployment of PTG technologies, thereby facilitating the integration of renewable energy sources and promoting sustainable energy solutions.

DOI： 10.1051/e3sconf/202346501011

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掲載種別：研究論文（学術雑誌）   出版者・発行元：International Communications in Heat and Mass Transfer  

The thermogravimetric method was employed to measure the adsorption kinetics of difluoromethane (R32) on MSC30 activated carbon powder adsorbent over a wide range of temperatures (25 °C to 150 °C) and pressures (up to 3000 kPa). The accuracy of various adsorption kinetics models, including FD model, LDF model, semi-infinite model, and modified adsorption kinetics models, were assessed to compare their suitability for predicting the kinetics uptake of the MSC30/R32 working pair. Based on the fitting of the Arrhenius equation, the activation energy Ea and pre-exponential coefficient [Formula presented] were calculated to be 6262.37 (kJ·kg−1) and 0.00853 (s−1), respectively. The MSC30/R32 pair exhibited the highest diffusion time constant and adsorption rate among the common MSC30/refrigerant pairs. Furthermore, a new mass transfer coefficient model was proposed to enhance the accuracy and broaden the range of applicability of the existing model (Jribi model). Comprehensive validations were carried out using various adsorbent-adsorbate pairs over a wide temperature range. The Jribi model in conjunction with the proposed mass transfer coefficient model achieved high accuracy and precision in predicting the adsorption dynamics of diverse working pairs, both during the initial stage and near the saturation state. This study provides valuable insight into the adsorption kinetics analysis, which is essential in accurately simulating adsorption systems for various applications, including refrigeration and air conditioning.

DOI： 10.1016/j.icheatmasstransfer.2023.107148

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Thermal Engineering  

Heat rejection pressure is an important factor influencing the performance of a CO2 (R-744) transcritical vapor compression system. Previous relevant studies have investigated the optimum heat rejection pressure ensuring the maximum coefficient of performance (COP) and operating parameters affecting the optimum pressure value. However, studies presenting quantitatively how much energy can save when an R-744 transcritical system operates in the optimum heat rejection pressure are still rather limited. This work aims to investigate an energy-saving potential gain achieved by managing heat rejection pressure in an R-744 transcritical system and provides quantitatively how much energy can save with that. In that way, this work tries to fill out the research gap. Simulations were carried out employing prevalidated model, the system COP was investigated in various operating conditions, and the optimum heat rejection pressure securing the maximum COP was found. The optimum heat rejection pressure found in this work was compared to the existing correlations, thereby the comparison results are provided in this paper. The system's dynamic performance was also investigated in two different cases: when the expansion valve opening was regulated for the optimum heat rejection pressure, and when the valve opening was adjusted with a thermostatic expansion valve conventionally. In this study, it is observed the given system reduces the compressor power consumption by 62% when the refrigerant temperature at the main gas cooler outlet varies within a range of 33 ℃ to 45 ℃ and the evaporator temperature of 1 ℃. Consequently, in terms of energy-saving potential, this paper highlights the importance of heat rejection pressure management in an R-744 transcritical system and the significance of proper selection for the control target of an expansion valve depending on the system's operating regime.

DOI： 10.1016/j.applthermaleng.2023.121397

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出版者・発行元：Chemical Papers  

In this research, carbon powder produced from bagasse, solid waste of sugarcane production, was used as raw material for creating screen-printed carbon electrode (SPCE), which is named SPAC600. Bagasse was carbonized at 600 °C under N2 flows to produce carbon. The carbonized bagasse was then treated with alkaline solution to leach out the impurities; therefore, the result, AC600, provides a significant increase in surface area from 24.8 to 197.10 m2 g−1. Alkaline treatment also changed the morphology of carbon powder into smaller flakes and removed C–H- aromatic vibration and C–O stretching within Fourier transformed- infrared (FTIR) spectra. The treatment also increases the electric conductivity from 10.01 S/cm to 25.39 S/cm. Alkaline leaching also increases the electrochemical performance of the electrode, proven by the significant increase of anodic current density, Ipa from 5.5 to 12.8 μA, for screen-printed carbon without alkaline leaching (SPC600) and SPAC600, respectively. Furthermore, ferrocene addition to the working electrode (WE) part of the prepared SPCE even increases the electrochemical performance as an analytic electrode, proven by the anodic current density of 173.0 μA. Even though the performance is still lower than a commercial SPCE which provides anodic current density up to 2000 μA, further treatment and modification may enhance the performance of the SPAC600.

DOI： 10.1007/s11696-023-02712-8

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出版者・発行元：AIP Conference Proceedings  

This work investigates a numerical study for titanium dioxide (TiO2) and carbon nanotube (CNT) nanofluid heat transfer performance. Nanofluid flowed in an inner concentric tube with circular, rectangular, and triangular channels were simulated using a mixture model in the Eulerian-Eulerian multiphase approach. The effect of Reynold number on fluid flow and heat transfer characteristic were observed. The results showed an increasing Nusselt number and a decreasing friction factor with an increment in Reynold number. Furthermore, the similar hydraulic diameter in circular, rectangular, and triangular tubes produced different mass flow rates of nanofluid flow inside the inner tube. The different mass flow rates affected their temperature distribution and Nusselt number. These results contribute to our understanding of how nanofluids enhance the heat transfer performance in various tube profiles.

DOI： 10.1063/5.0114128

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Communications in Heat and Mass Transfer  

Adsorption heat transformer (AHT) cycles, unlike adsorption cooling cycles, upgrade the heat source to a higher temperature. Despite the renewed interest in the AHT cycles, its performance enhancement schemes along with their impacts are yet to be explored extensively. Heat and mass recovery schemes on the adsorption cooling/heating cycles have been extensively studied. However, AHT cycles are fundamentally different from those cycles since the AHT cycles employ isothermal-adiabtic processes. Thus, similar impacts of the heat and mass recovery scheme as in the cooling/heating cycles cannot be expected in AHT cycles. Therefore, the impacts and limitations of the internal heat recovery scheme on the AHT cycle are investigated in the current study. The heat recovery scheme aims to minimize the requisite uptake consumption for preheating the adsorber bed by recovering the sensible heat between two adsorber beds having different temperatures. This sensible heat exchange is modeled using modified energy-balance equations to capture the non-linearity of the adsorption process. The preheating uptake loss decreases from 0.014 kg/kg to 0.007 kg/kg at the heat source-heat supply temperature combination of 60 °C–80 °C due to the maximum possible heat recovery in the AHT cycle. As a result of the reduced preheating uptake loss, approximately 5&#37; and 10&#37; increase in the useful heat ratio and exergy efficiency of the AHT cycle, respectively are obtained. This modified AHT cycle further improves the performance ratio of the hybrid AHT-MED (multi-effect distillation) system from 4.6 to 4.9 at the heat source temperature of 58 °C. Furthermore, a parametric analysis of the cycle's performance metrics has been conducted for various degrees of heat recovery, representing the effect of realistic heat exchanger effectiveness during the recovery process. This study will help propel the theoretical development of the adsorption-based thermodynamic systems.

DOI： 10.1016/j.icheatmasstransfer.2023.106774

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記述言語：その他   掲載種別：研究論文（学術雑誌）  

Vortex generators (VGs) in the form of small fins are attached to the blade of the H-rotor wind turbine to improve the performance. Many studies provide the utilization VGs both experimentally and numerically. However, the investigation of the full scale of counter-rotating VGs in rotor blades is still rarely found. In the current study, two shapes of VGs were investigated to evaluate wind turbine performance. VGs in rectangular and triangular shapes were attached under the identical blade geometry of 375 mm of chord length and the blade attachment of 30&#37; from the chord length. VGs have a similar height and length of 6.5 mm and 13 mm, respectively. The turbine was constructed with three blades that rotate under 1,650 mm of the rotor diameter and 1,000 mm of rotor height. The chordwise position (x/c) of the VGs was at 10&#37;, 15&#37;, 20&#37;, and 25&#37;. The computational fluid dynamics with the unsteady Reynolds Average Navier Stokes (URANS) model were employed. We found that VGs behave in different performances. The rectangular VGs had the maximum power coefficient (Cp) value at the x/c of 20&#37;, while the triangular VGs had the maximum Cp value at the x/c of 25&#37;. However, both VGs show the maximum Cp in the value of 0.467 with a 1.5 Tip Speed Ratio. To evaluate the performance improvement, the blade with VGs was compared with the blade without VGs. It was found that using the VGs improved the performance of the wind turbine by around 45.68&#37; and 47.24&#37;, respectively, for triangular and rectangular shapes. The flow field characteristics in terms of turbulent kinetic energy and flow velocity were also presented in this study to gain a better understanding of how the VGs work. The result revealed that the presence of the VGs significantly improves the performance of the turbine.

DOI： 10.5109/6781073

記述言語：日本語   出版者・発行元：一般社団法人 日本機械学会  

<p>Adsorption technology has attracted much attention for gas storage and heat-driven adsorption heat pumps due to its low cost and recyclability. Metal-organic frameworks with high porosity have become ideal adsorbents in recent years due to their high adsorption capacity. We simulated the adsorption of CH4 in HKUST-1 using molecular dynamics. The methane uptake was calculated from the adsorption kinetic curves and compared with experimental values. The relationship between thermodynamic properties such as the thermal conductivity of the adsorption phase based on the adsorption amount was also analyzed.</p>

DOI： 10.1299/jsmepes.2023.27.d211

CiNii Research

記述言語：英語   出版者・発行元：一般社団法人 日本機械学会  

<p>This study presents a predictive model utilizing artificial neural networks (ANNs), specifically Multilayer Perceptron (MLP) and Deep Neural Networks (DNN), to forecast the properties of activated carbon under various experimental conditions. The prediction model focuses on the Brunauer-Emmett-Teller (BET) surface area and total pore volume of the activated carbon, with the carbonization temperature, activation temperature, and activation agent as the determining factors. A dataset comprising around 100 samples was used for training the model and testing its accuracy. Results indicate that the DNN model, despite its increased complexity, exhibits superior performance over the MLP model in predicting the properties of activated carbon. The DNN model showed a Mean Absolute Percentage Error (MAPE) of 14.19% for the BET surface area prediction and 17.90% for the total pore volume prediction. The findings underscore the potential of using DNN models in optimizing activated carbon production processes and tailoring its properties for specific applications. Nonetheless, the study suggests the need for expanding the dataset and including more influential factors to further enhance the model's accuracy and reliability.</p>

DOI： 10.1299/jsmepes.2023.27.d212

CiNii Research

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Environmental Science and Engineering  

Particulate matter (PM) accumulation on the leaves of two trees and two shrubs were examined for 14 days to study the ability of broad leaves to capture particulate matter in Japan. Two healthy mature leaf samples of each specimen were carefully collected and analyzed through the gravimetric analysis method (four filtration steps). PM in different divisions can be captured and deposited inside the leaf foliage. Fine particles were the highest portion of the PM content captured by the analyzed trees. Leaf features such as hair and wax have been associated with high PM accumulation as presented in Toxicodendron succedaneum (waxy glossy leaves) which was the most effective species among the analyzed species for all PM fraction divisions (PM10, PM 2.5, and PM 0.2), and Prunus × yedoensis (hairy leaves) that captured the largest portion of ultra-fine PM. The surface area has no effect on the accumulation of particulate matter since the Ficus erecta shrub has the largest surface area, but the lowest portions of PM among of the investigated species.

DOI： 10.1007/978-981-99-4101-8_20

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出版者・発行元：Applied Energy  

Adsorption desalination is prescribed as a promising and eco-friendly solution for mitigating water scarcity, owing to its utilization of low-grade thermal waste and zero liquid brine discharge. The keystones that regulate the performance of the adsorption desalination system (ADS) include nature of adsorbents, system design, and operating conditions. The present study aims to provide a state of the art review on the keystones of ADS. Metal-organic frameworks (MOFs) hold remarkable adsorption capacity and tunable structure. However, hydrothermal instability, high cost, and complex synthesizing procedures are the potential challenges that need to be addressed. The technological advancements in ADS have been classified into: (i) Conventional Approach, (ii) Heat and Mass Recovery Approaches, (iii) Hybridization Approaches, (iv) and Adsorbent Substituting Approach. The study provides critical insight and compares the performance of each approach based on specific daily water production (SDWP), specific cooling power (SCP), and coefficient of performance (COP). The conventional ADS produce SDWP of 4.7 m3/ton/d, however producing zero and/or minimal SCP while using payable energy of 1.50 kWh/m3. In heat/mass recovery approaches, pressure equalization-valve delay schemes and master–slave configuration provide ∼ 5 % additional water adsorption/desorption on/from silica-gel and reduce ∼ 50 % thermal heating load, respectively. Evaporator-condenser amalgamation emphasizes the evaporator temperature of 30–42 °C leading towards ∼ 69 % higher SDWP with zero SCP. Dual stage, multi evaporators/condensers scheme is found supportive in cogenerating feature of ADS thereby improvising COP to ∼ 0.87. In hybridization approach, ejector integrated ADS produces SDWP of 80 m3/ton and COP of 2.22 using payable energy of 0.92 kWh/m3, however, needs experimental validation. In the adsorbent substituting approach, CPO-27(Ni), Emim-Ac/Syloid 72FP, and composite adsorbent manifest the SDWP to higher levels. The operating conditions are sensitive and need to optimize depending on the configuration of ADS. Possible future research directions may include efficient designing/ sizing of evaporators/ condensers, minimizing the heat and mass transfer resistances in adsorber/desorber reactor, optimize the thickness of the adsorbent layer in heat exchangers, and investigating wide range of adsorbent classes that can be driven with very low regeneration temperature.

DOI： 10.1016/j.apenergy.2022.120101

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Air-Conditioning and Refrigeration  

Thermally driven desiccant- and evaporative cooling-based technologies are promising greener and cheaper alternatives to compressor-based systems due to the separate handling of latent and sensible loads. Desiccant air-conditioning (DAC) systems comprise a desiccant dehumidifier, a sensible cooling unit, a heat source for regeneration, and a heat recovery unit. These components of a DAC system can be arranged in various ways to give different configurations with varying advantages and disadvantages. In this study, five configurations of thermally driven desiccant dehumidifier- and dew point evaporative cooling (DPEC)-based DAC systems were investigated. Seven evaluation criteria namely regeneration temperature, desiccant moisture removal capacity, COPt, DPEC L/H, heat exchanger UA, system size, and fan power requirement were employed. Results show that the standard cycle in ventilation mode offers the highest COPt despite having the highest regeneration temperature. Recirculation of the return room air can operate at a significantly lower regeneration temperature at the expense of larger equipment size and much lower COPt. DAC with an internally cooled dehumidification can operate at low regeneration temperature at the expense of higher fan power and slightly lower COPt. Dividing the dehumidification process into two stages can offer operation at moderately lower regeneration temperature without severely affecting the other criteria. This study can serve as a guide for the selection of an appropriate DAC configuration for space cooling depending on the objective criteria and the resources available.

DOI： 10.1007/s44189-022-00011-7

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：九州大学大学院総合理工学府  

Dew point evaporative cooling (DPEC), a type of indirect evaporative cooling where a single stream of air flows sequentially through the dry and wet channels, can cool air theoretically to its dew point temperature. In this study, the effects of design parameters, operating parameters, and inlet air condition to the cooling performance of a counter-flow DPEC was investigated. It has been shown that for the nominal condition of channel length = 1m, channel height = 5mm, inlet air velocity = 1.5 m/s, and working air ratio = 0.3, the inlet air with temperature of 30o C and humidity of 0.010 kg/kg da was cooled to 19.3oC which is lower that its wet bulb temperature of 19.6oC. The temperature can be cooled further by increasing the channel length, decreasing the channel height, decreasing the inlet air velocity, or increasing the working air ratio.

DOI： 10.5109/5909100

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：九州大学大学院総合理工学府  

Nuclear energy has been considered as clean and environmentally friendly method of power production. With the emergence of Generation IV reactor, a new horizon was opened in nuclear technology. The invention of new materials and production processes and magnetic bearings, the new ideas for increasing the efficiency of nuclear power plants are being considered more feasible. In this paper the thermodynamic analysis of a Helium pseudo-isothermal expansion and compression power cycle which can be utilized to couple with a Very High-temperature Gas Reactor (VHTR) was performed. A novel thermodynamic modelling of estimating the isothermal process based on the irreversibility during the compression or expansion was done. The results show that isothermal process is not so far from the reality and the power cycle can exceed other designs in terms of efficiency.

DOI： 10.5109/5909105

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記述言語：その他   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/app122010630

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出版者・発行元：Heat Transfer Engineering  

Heat and mass transfer characteristics (HMTCs), which defined the latent and sensible load, are essential for developing an effective desiccant dehumidification system (DSDHS). Therefore, the current work provides an investigation on the HMTCs, in the form of the Nusselt and Sherwood numbers. Under constant adsorption temperature of 293 K, the HMTCs were analyzed with three different regeneration temperatures of 308 K, 318 K, and 328 K. While the velocities were kept constant of 0.1 kg/s both for adsorption and regeneration processes. The DSDHS used the polymer material having the highest adsorption capacity of 0.78 kg/kg. Using the thermal and mass resistance approaches, the heat, and mass transfer coefficients were able to predict. The results show that the highest regeneration temperature revealed the most top differences between the humidity ratio inlet and outlet, which was 2.2 g/kg. The Nusselt number values, as well as Sherwood number, tend to increase with the rise of regeneration temperature. The proposed empirical correlation for predicting the HMTCs was followed by the experimental data with a maximum discrepancy of 17%. It is suggested that the properties of the interface must be carefully acquired to reduce the discrepancy between the experimental data and analytical.

DOI： 10.1080/01457632.2021.2000582

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Sustainable Energy Technologies and Assessments  

Humidification-dehumidification desalination (HDD) systems offer a feasible approach for the production of fresh water in inaccessible areas as they can be operational using renewable energy and require little maintenance. Various studies are being carried out to boost the system performance. In this paper, an open air open water HDD system is proposed that exploits the enhanced evaporation and condensation processes by implementing with the Maisotsenko cycle (M-cycle). The system utilizes solar energy as the energy input to heat the saline water. A thermodynamic model is formulated under steady-state conditions, considering the first and second law of thermodynamics. The energetic and exergetic performance of the system is studied. The model is first validated with the experimental data and a good agreement is found where the maximum discrepancy is about 6.0 &#37;. Effects of different operating conditions on key performance parameters such as the Gain Output Ratio (GOR), specific energy consumption (SEC), exergy destruction, and exergy efficiency are analyzed. An improvement is observed in the GOR when the inlet air temperature is raised at constant humidity ratio. The system exhibits better performance in dry air environment when compared with humid air environment. The analysis shows a maximum mass flow rate of desalinated water of 22.3 kg/h, recovery ratio (RR) of 0.223, GOR of 3, SEC of 0.23 kWh/kg and an exergy efficiency of 43.21 &#37;.

DOI： 10.1016/j.seta.2022.102141

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Ambient Energy  

Simulation-based assessment is performed here by using the single-phase model (S-PM) and the two-phase mixture model (T-PMM). The models are used to investigate the heat transfer performance of TiO2/water nanofluids inside a circular tube with a diameter of 1.09 mm and a length of 306 mm. Reynolds numbers are varied from 600 to 2100, while the nano-particle concentration is 1.0, 2.0, 3.5 and 5.0 vol.&#37;. Higher friction factor (f) and convective heat transfer coefficient (h) were observed for titania-based nanofluids compared to those of the base fluid (water). Heat transfer performance of the nanofluid increases as the nanoparticle concentration is increased. Likewise, the augmentation in pressure drop increases with nano-particle concentration. The highest enhancement in the Nusselt number of 14.81&#37; was observed for nanoparticles with a concentration of 5 vol.&#37; at the Reynolds number of about 1500.

DOI： 10.1080/01430750.2022.2085797

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Energy  

Recovery of the low-temperature waste heat for electricity generation has been gaining a significant interest. An Inverted Brayton Cycle (IBC) is often employed to convert the low-temperature waste-heat to electricity while the thermal efficiency and specific work output are poor. In this paper, a new energy recovery scheme is introduced incorporating the IBC with a Regenerative Heat and Mass Exchanger (RHME). The RHME is a heat and mass exchanger that consolidates a recuperator (for thermal efficiency improvement) and an Indirect Evaporative Cooler (for enhanced specific work). Numerical models for RHME and the IBC were judiciously developed where possible condensation in the product air channel was accounted for. The model was validated with the experimental data and the cycle was investigated for various waste-heat sources (50–150 °C). When compared to a conventional air-cooling IBC system, incorporating the current energy recovery scheme increases the thermal efficiency from 8.13&#37; to 14.36&#37; and specific work output from 10.38 to 12.46 kJ/kg equivalent to 76.63&#37; and 20.1&#37; improvements, respectively. The unprecedented performance improvement is realised from the exploitation of the regenerative and air-saturation (cooling) mechanisms for both energy recovery and cooling of the working fluid.

DOI： 10.1016/j.energy.2022.123726

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Thermal Analysis and Calorimetry  

The desiccant dehumidification system can separate the latent heat and sensible heat in the air-conditioning system and achieve energy savings by removing latent heat. Industrial waste heat and renewable energy could be utilized in desiccant dehumidification systems, where the desorption process can be performed below 70 °C. The vapor pressure and temperature of the regenerating air dictate the desorption process corresponding to the isotherm properties. This study has focused on the effects of various temperatures and humidity ratios of regeneration air on the performance of a desiccant dehumidifier using a polymer as an adsorbent. Experiments were performed using the regeneration air with the humidity ratios of 0.005 kg kg−1, 0.010 kg kg−1, 0.015 kg kg−1, and 0.020 kg kg−1, while the air temperatures were varied from 40 °C to 70 °C. The evaluation of this study employs the adsorption/desorption amount, average moisture removal capacity, and latent energy ratio (LER) of the regeneration process as key performance indexes. At the regeneration temperature of 68 °C, the peak desorption amount at the humidity ratio of 0.005 kg kg−1 and 0.010 kg kg−1 both reached 0.011 kg kg−1. The results indicated that the higher desorption temperature led to a higher desorption amount. Besides, with the increased desorption temperature, the average moisture removal capacity increases. In contrast, the high humidity ratio of regeneration air resulted in a weak dehumidification ability. Lower regeneration temperature was difficult to apply to regenerate the polymer-based desiccant under a high-humidity-ratio atmosphere. To attain a high LER, a lower humidity ratio of dry air and regeneration temperature was preferred. The regeneration air with a humidity ratio of 0.020 kg kg−1 is not suitable to apply in the dehumidification system in the temperature range of 40–70 °C.

DOI： 10.1007/s10973-022-11368-7

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Thermal Analysis and Calorimetry  

Adsorption heat transformers (AHTs) are considered as promising systems for upgrading waste heat to a higher temperature. The cycle operates among three temperature reservoirs: (i) heat sink at the low temperature (TL), (ii) heat source at the medium temperature (TM), and (iii) heat supply at the high temperature (TH). In the present study, the performance the AHT cycle was analyzed for possible applications in the waste heat upgrade and thermal desalination. An equilibrium model was developed using adsorption characteristics and isotherm data. Five types of commercially available silica gels and three types of zeolites were investigated as adsorbents. Nonlinear optimization technique was utilized for the determination of the intermediate pressure and uptake for preheating and precooling phase of the AHT cycle. The performance parameters in terms of useful heat ratio and condensation heat ratio were determined and compared for the reservoir temperatures at 30 °C (TL)—60 °C (TM)—80 °C (TH). Parametric evaluation of the performance parameters was carried out based on the variation in gross temperature lift, as well as the heat exchanger mass ratio. It was found out that reduction in the gross temperature lift had a positive impact on the useful heat ratio and a negative influence on the condensation heat ratio of the AHT cycle. Significant variations in the maximum adsorption capacity and slope of the isosteric heat of adsorption across various adsorption pairs containing zeolites were observed. As a result, AQSOA-Z01 zeolite exhibited the highest heat exchange values of the AHT cycle in the range of ~ 320–370 kJ per kg of adsorbent. On the contrary, type AQSOA-Z02 zeolite displayed the lowest corresponding values in the range of ~ 60–90 kJ kg-1 of adsorbent. On the other hand, variation across the different silica gel adsorbents was comparatively smaller because of similar isotherm and isosteric heat of adsorption characteristics. This study will assist the research on the theoretical development of the AHT cycle via material selection and system design optimization.

DOI： 10.1007/s10973-022-11350-3

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記述言語：英語   出版者・発行元：公益社団法人 日本冷凍空調学会  

<p>With the increase in energy consumption, energy-saving attracts lots of attention. The desiccant dehumidification system is a potential substitute for the air-conditioning system that can achieve energy saving by decreasing the energy input for latent heat. Besides, the desiccant dehumidification system can further utilize the low-temperature heat waste in the desorption process. Thus, this study has focused on the low temperatures range between 40ºC and 70ºC on the desorption process with low humidity ratios of dry air as 0.005 kg/kg. The results indicate that, with the increasing desorption temperature, the water removal amount also increases, which means the ability of dry air to capture moisture from desiccant increases with higher temperature. At the desorption temperature of 68ºC, the average moisture removal capacity reached the peak, 0.0081kg/kg. Conversely, the coefficient of performance (COP) of the desorption process presented a downward trend with increasing desorption temperature. At desorption temperature 41ºC the COP is highest at almost 0.8, then gradually dropped to around 0.51 at desorption temperature 68ºC. The optimal desorption temperature can be determined as 54ºC.</p>

DOI： 10.11322/tjsrae.21-40de_em_oa

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記述言語：英語   出版者・発行元：公益社団法人 日本冷凍空調学会  

<p>Nanotailored microporous silica represents one of the more recent artificially prepared advanced materials used in heat transformation and conservation field after silica gel and various zeolite and zeolite-like materials. In this work, we introduce experimental findings on the energy characteristics of water adsorption on nanotailored microporous silica with 1.5 % aluminium doping in the structure. The downscaled system in this work simulates actual working conditions in a controlled environment for both heating and cooling mode. The key properties of this material lie in the regeneration temperatures 60 to 80 ℃ and COP, which reaches values around 0.6 in case of cooling and 0.7 in case of heating. In absolute values at Δ<i>T</i> = 15 ℃, the system reaches storing capacities of about 90 Wh and 126 Wh per adsorbent kilogram in terms of cooling and heating potential energy, respectively. An important factor of kinetic influence on system performance is discussed on a basis of constant time experiment and time-dependent energy flow breakthrough analysis. Constraining factors are found to be in parallel through the driving force of the pressure swing as well as the heat transfer through the body of the adsorption bed.</p>

DOI： 10.11322/tjsrae.21-37de_em_oa

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記述言語：英語   出版者・発行元：公益社団法人 日本冷凍空調学会  

<p>Water vapor adsorption on activated carbon (AC) for dehumidification purposes has gained much attention due to the abundance of benefits provided by AC. The working region limited in high water vapor relative pressure (<i>P/P0</i>) makes this material suitable only for removing water vapor at a highly humid region. In this study, ozone oxidation was conducted to introduce more oxygen-based functional groups on AC to attract more water molecules. Based on surface characterization results, ozone oxidation increases oxygen functional groups such as carboxylic on AC but decreases their pores. The more AC exposed to ozone, the more different properties could be observed. The increment of functional groups enhances the water vapor adsorption uptake at <i>P/P0</i> ≤ 0.6, shifting the water sorption into lower <i>P/P0</i>.</p>

DOI： 10.11322/tjsrae.21-36de_em_oa

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Refrigeration  

R1132(E) (trans-1,2-difluoroethylene, C2H2F2) is a potential next generation refrigerant to be utilized in air conditioning applications. This hydrofluoroolefin (HFO) refrigerant possesses an extremely low-GWP value below 1 and it is an excellent candidate for replacing R32 in blends such as R410A, which are subjected to local and international greenhouse gas regulations for limiting global warming. Two isochoric apparatus were used to measure the saturation pressures of R1132(E) from 240 K to its critical temperature. At the critical temperature, the critical pressure of R1132(E) was also directly measured. Twenty-four saturation pressures including the critical point were used for optimizing a Wagner-type equation representing the saturation pressure curve. The absolute average deviation of the saturation pressures of R1132(E) predicted by the model using the fitted parameters and the experimental data is 0.02&#37;. The optimized Wagner-type equation of saturation pressures is used for determining the acentric factor of R1132(E) as 0.2433, which is further utilized for the prediction of the saturation pressures using the Peng-Robinson cubic equation of state within an absolute average deviation of 0.31&#37;.

DOI： 10.1016/j.ijrefrig.2021.12.014

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人日本機械学会・社団法人日本伝熱学会  

Renewable energy-based microgrid systems are widely being studied as electrification methods for rural communities in developing countries. Waste heat generated by the components of the microgrid systems, such as the biogas driven generators (BDG), presents the potential of utilizing the low-grade heat in a way that can contribute to the sustainability of such energy systems. From the points of view of affordability, local manufacturability, and applicability for agriculture, thermally driven pumps (TDP) may be attractive for coupling with such microgrid systems. Therefore, the current study has focused on the development of a new type of thermally driven pumping system as a potential waste heat utilization component for microgrid applications in rural areas. A liquid piston-type TDP concept without moving parts, except few valves, was developed and parametric experimental investigations were carried out. The performance and characteristics of the system were studied, which revealed that the proposed system has a superior performance compared to the literature. It was also found that the system performance strongly depends on the heat addition rate and delivery capacity of the system, which are suitable characteristics for the intended application. Hence, the experimental data were used to estimate whether the proposed system can pump enough water that needs to be supplied for the biogas production to supply a 10 kW BDG unit of a microgrid. It was found that 87 – 93&#37; of the total pumped water (13 – 27 m3) would be available for agricultural and other purposes while only 6 – 13&#37; would need to be fed to the biogas digester. Generally, the results seem to be promising, and yet there are potentials for the optimization and improvement of the proposed system, hence they have been pointed out.

DOI： 10.1299/jtst.21-00323

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Energy  

Multi-effect distillation (MED) systems are considered to be the most energy-efficient thermal desalination methods. This paper introduces the development of a novel thermal desalination system for performance superior to MED systems for the same operating temperature limits. Such an unprecedented achievement was attained by upgrading the heat source using the chemical potential of adsorption phenomena. The proposed Adsorption Heat Transformer (AHT) cycle hybridized with Multi-effect distillation system (AHT-MED) exhibits higher performance ratio and water production rate than a conventional MED system for the same heating source and sink. The heat generated by the heat of adsorption with the temperature higher than the heat source is supplied to the first effect of the MED system, thus, extending the temperature difference between the Top Brine Temperature (TBT) and Bottom Brine Temperature (BBT). The higher temperature difference offers more number of effects, with the equivalent temperature difference between the effects (ΔTe) as the design parameter. Using the low-temperature heat source (as low as 58 °C), the system can employ an increased number of effects (as high as 11) due to the supply of heat at an increased temperature of around 80 °C. The proposed system achieves a higher performance ratio (approximately 5.4) and water production rate (2 kg/s) compared to the standalone MED system (PR: 4.2, WPR: 1 kg/s) with the number of effects of the hybrid system as 10 at constant interstage temperature difference between the standalone and hybrid systems. This novel AHT-MED system opens up new possibilities for low-temperature heat source-driven thermal desalination with significantly improved performance.

DOI： 10.1016/j.apenergy.2021.117744

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記述言語：その他   掲載種別：論文集(書籍)内論文   出版者・発行元：Green Energy and Technology  

The poultry industry is a major contributor to worldwide food production. Poultry birds are fatally sensitive to humidity and temperature. Therefore, a temperature/humidity control system is principally required for optimum growth of the birds. Conventionally, to regulate temperature/humidity in control sheds, vapor compression air-conditioning systems are used which are not only costly but also consume an enormous amount of primary energy. Alternatively, evaporative cooling pads are also used which increase humidity level inside control sheds results in various fungal diseases. In this regard, this study explores desiccant air-conditioning (DAC) options for climatic conditions of Multan (Pakistan). These systems are operated with thermal energy that could be available via low-grade waste heat and renewable energy options. Such systems would allow the development of poultry houses in off-grid remote areas which eventually support the green smart grid’s philosophy. Two DAC options are studied which are involved in standalone DAC and evaporative cooling (EC) assisted DAC concepts. Psychrometric and thermodynamic analysis with two types of desiccant materials is used in the study (i.e., silica-gel and hydrophilic polymeric-sorbent). The study determined body-weight-gain, feed-conversion-ratio, sensible/latent heat, and temperature-humidity-index of birds. As such, the performance of the proposed systems is investigated for cooling capacity and COP. According to results, the EC-assisted polymeric-sorbent system has resulted feasible in terms of maximum cooling capacity and COP. This system could achieve thermal comfort of birds at THI of less than 30 °C.

DOI： 10.1007/978-3-030-90720-4_16

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記述言語：日本語   出版者・発行元：一般社団法人 日本機械学会  

<p>In the current study, the enhancement of evaporation rate for a thermally driven pumping system was investigated experimentally. Porous copper insert of variable density was applied into the evaporation chamber of the system as a method of evaporation enhancement. The investigation was carried out in a TDP system that was developed for waste heat utilization from microgrid system for rural area applications. The experiment results showed a variable level of evaporation rate and the thermal efficiency of the system. The observed general trend is that the heat transfer rate and the delivery flow rate of the system are improved significantly with the decrease of the porosity of the mesh while the thermal efficiency of the system shows an optimum level. The enhancement method resulted in 47 – 144 % increment of the heat transfer rate and 38 - 186% increment in the delivery flow rate of the system in comparison to the case where no porous mesh was used. Generally, the results seem to suggest that the enhancement method could be promising for the intended application.</p>

DOI： 10.1299/jsmepes.2022.26.e134

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記述言語：英語   出版者・発行元：一般社団法人 日本機械学会  

<p>Dew-point evaporative cooling is an air conditioning technology which has possibility of achieving lower temperature, higher efficiency, lower water consumption. Understanding the heat and mass transfer principles of the system is crucial for the applications. This study presents a mathematical model which is conducted to (1) study the heat and mass transfer processes under different initial condition; (2) analyze the factors affecting the performance of system. And an experimental setup has been adopted to give a validation for the numerical model</p>

DOI： 10.1299/jsmeenv.2022.32.1402-07-06

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：International Exchange and Innovation Conference on Engineering and Sciences  

In order to utilize the adsorption chiller or heat pump as a next-generation air conditioning system, several issues still remain, such as performance improvement, miniaturization, and cost reduction. It is known that the activated carbon-freon refrigerant pair has a relatively lower coefficient of performance (COP) than the silica gel-water or freon refrigerant pair and zeolite-water pair. However, there is a possibility to contribute minimize the adsorption heat pump system utilizing Freon refrigerant since it works in high-pressure regions and has a high saturation vapor density. Therefore, evaluating and improving the performance of Freon refrigerant is an important future task.

DOI： 10.5109/5909083

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記述言語：その他  

Zero-energy cool chamber (ZEC) was built in this study to extend the shelf/storage life of tomatoes. Tomatoes were stored in ZEC, room, and outside conditions to evaluate the performance of the chamber. Physico-chemical analyses of stored tomatoes were performed at regular intervals. These analyses include physiological weight loss (PWL), visual appearance (VA), total soluble solids (TSS), titratable acidity (TA), and pH. The physico-chemical properties of ZEC stored tomatoes were compared with those stored in the outside (OS) and room (RM) conditions. The average cooling efficiency of ZEC was determined as 89&#37;. The ZEC maintained the qualitative, quantitative, and nutritive attributes of tomatoes by slowing down the respiration and/or transpiration rate. Tomatoes stored in ZEC were useable and marketable on the 40th day of storage. On the other hand, tomatoes stored in RM and OS condition were decayed on 12th and 16th day of storage, respectively. Therefore, ZEC is a low-cost, zero-energy, and environment-friendly option for the short-term storage of tomatoes.

DOI： 10.1007/978-3-030-86394-4_5

記述言語：その他  

Poultry industries play a major role in Pakistan’s economy as well as developing countries. Poultry birds are sensitive to slight variation in ambient air temperature and humidity. Therefore, temperature-humidity control system is principally required for optimum growth of the birds. Conventionally, vapor-compression-based air-conditioning systems are used in poultry houses to control temperature and humidity. These systems degrade the environment and consume huge amount of primary energy. In this regard, the present study investigates energy-efficient thermally driven desiccant dehumidification-based evaporative cooling system for monthly basis climatic conditions of Multan (Pakistan). The present study explored standalone desiccant air-conditioning system (S-DAC) and Maisotsenko cycle assisted DAC system (M-DAC) using silica-gel and hydrophilic polymeric-sorbent desiccant materials from the viewpoints of slope of dehumidification line, dehumidification capacity, cooling capacity, and coefficient of performance (COP). In addition, the study explored surface temperature, surface area, total sensible heat loss, evaporative heat loss, total heat loss, and temperature-humidity index (THI) of the poultry birds. The results showed that the polymer-based M-DAC system was feasible in terms of maximum dehumidification capacity, cooling capacity, and COP (i.e., 4.3 g/kg-DA, 14.9 kJ/kg, and 0.5, respectively) and achieved thermal comfort (THI < 30℃) of poultry birds throughout the year.

DOI： 10.1007/978-3-030-86394-4_2

記述言語：その他  

Fresh fruits and vegetables are perishable and possess short life under ambient conditions. Post-harvest losses are one of the major concerns in the storage of fruits and vegetables. In this regard, proper control of temperature and humidity is required to reduce post-harvest losses and enhance the shelf life of fruit and vegetables with the finest quality, quantity, and nutritive attributes. Several options such as vapor compression-based air-conditioning systems have been studied and implemented worldwide for possible storage of fruits and vegetables but consume a huge amount of energy and degrading the environment. Therefore, in this study, the energy-efficient standalone desiccant air conditioning (DAC) and Maisotsenko cycle-based desiccant air conditioning (M-DAC) systems were explored from the viewpoint of potential storage of fruits and vegetables. The systems analysis to check the feasibility was carried out in the climatic conditions of Multan, Pakistan. The proposed systems were thermodynamically explored from the viewpoint of ideal temperature and humidity control storage zones, cooling capacity, and coefficient of performance (COP). The results appreciably showed that the M-DAC system performed relatively better than the proposed standalone DAC system. It was found that the cooling capacity and COP of the M-DAC system were found 32.5 kJ/kg and 1.07, respectively, as compared with standalone DAC.

DOI： 10.1007/978-3-030-86394-4_4

記述言語：その他  

This study provides insights into the applicability of evaporative cooling systems for livestock air conditioning (AC) for the climatic conditions of Multan (Pakistan). Usually, direct evaporative cooling systems are used in Pakistan which are inefficient and fail to achieve the required temperature and humidity levels for livestock thermal comfort. Therefore, three different types of evaporative cooling i.e., direct evaporative cooling (DEC), indirect evaporative cooling (IEC), Maisotsenko cycle evaporative cooling (MEC) systems, and desiccant dehumidification hybrid evaporative cooling (M-DAC) system, are explored for livestock air conditioning in Multan. The study aims to explore the best livestock AC option from the viewpoints of temperature gradient, temperature-humidity index (THI), and system performance. The MEC and M-DAC systems could achieve the required livestock thermal comfort. The DEC system achieved maximum effectiveness i.e., 0.9, whereas, it was 0.55 and 0.65 in case of the IEC and MEC systems. In addition, the M-DAC system achieved highest temperature gradient (i.e., 20 °C), whereas it was 10.5, 9.3, and 7.1 °C in case of the DEC, MEC, and IEC systems. The MEC and M-DAC systems achieved optimum temperature-humidity-index for livestock thermal comfort (i.e., 68–72). Thus, the study concludes the M-DAC system as an optimum system for livestock AC.

DOI： 10.1007/978-3-030-86394-4_3

記述言語：その他  

The air conditions inside wet markets may affect the human health, and the quality of food products. Humid conditions promote the growth of pathogenic micro-organisms that lead towards certain human diseases and loss of products’ qualitative and nutritional attributes. It highlights the importance of air-conditioning to sustain environmental health in wet markets. Two energy-efficient air-conditioning/cooling systems, i.e., standalone Maisotsenko evaporative cooling system (S-1) and desiccant air-conditioning system (S-2), were proposed in this study. These systems were investigated for their applicability in wet markets under ambient conditions of Punjab, Pakistan. The study area was divided into three climatic zones due to the spatio-temporal variations. The results revealed that the proposed system S-1 was applicable during April and May, while S-2 was suitable in critical months (June, July, August, and September) in all the climatic zones. The system (S-2) performance was further evaluated based on thermal coefficient of performance, wet-bulb, and dew-point effectiveness.

DOI： 10.1007/978-3-030-86394-4_6

記述言語：その他  

Agricultural products storage and postharvest losses are linked with optimal temperature humidity conditions. In this regard, desiccant air-conditioning (DAC) technology is investigated due to its ability to control the temperature and humidity distinctly. Six kinds of evaporative cooling-assisted DAC system configurations are thermodynamically investigated using heat/mass transfer balance for climatic conditions of Fukuoka (Japan). In case of S-II, S-IV, and S-VI configurations, there are no direct evaporative cooler (DEC) in regeneration air stream. These configurations provided higher dehumidification with less regeneration heat due to provision of regeneration air stream to heat exchanger at high dry bulb and low dew point temperatures. System configuration S-V achieved higher cooling capacity and thermal COP due to consideration of DEC on regeneration air stream without considering indirect evaporative cooler on supply air stream. Three efficient configurations (S-II, S-IV, and S-V) are further evaluated for agricultural product storage and other applications. The S-II configuration achieves latent load at regeneration temperature of 80 °C; however, the modification of two-stage cooling is suggested in S-II to achieve the sensible load for storage of agricultural products. It can also employ for greenhouse air conditioning even at low regeneration temperature depending upon the type and growth stage of the crop.

DOI： 10.1007/978-3-030-86394-4_1

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Indoor air humidity plays a vital role in determining occupants’ health and industrial product quality. Removing excess humidity by adsorption dehumidification is still facing a challenge in finding a suitable material with high adsorption capacity and low regeneration temperature. In this study, the theoretical dehumidification capacity of prepared acorn nutshell-based activated carbons was calculated and compared with silica gel type RD and RD-2060. The calculation was based on the outdoor air condition in two Asian capital cities: Jakarta and Tokyo. The theoretical study found that prepared activated carbon has better dehumidification performance under Jakarta conditions using regeneration temperatures of less than 60°C. Under Tokyo conditions, activated carbon shows auspicious performance during the summer season. Compared with silica gels, acorn nutshell-based activated carbon has a better dehumidification capacity to process high humidity ambient air with a lower regeneration temperature.

DOI： 10.1016/j.ijrefrig.2021.08.012

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Adsorption-based desalination (AD) is an emerging concept to co-generate distilled fresh water and cooling applications. The present study is aimed to provide a comprehensive review of the adsorption desalination systems and subsequent hybridization with known conventional cycles such as the multiple-effect AD (MED), solar regenerable, integrated evaporator-condenser cascaded, and ejector integrated systems. The systems are investigated for energy consumption, productivity enhancement, and performance parameters, including production cost, daily water production, and performance coefficient. Comprehensive economic aspects, future challenges, and future progress of the technologies are discussed accordingly to pave researchers' paths for technological innovation. Traditional AD systems can produce specific daily water production of 25 kg per kg of adsorbent. The solar adsorption desalination-cooling (ADC) showed a promising specific cooling power of 112 W/kg along with a COP of 0.45. Furthermore, for a hybrid MEDAD cycle, the gain output ratio (GOR) and performance ratio (PR) is found to be 40&#37;, along with an augmented water production rate from 60&#37; to two folds. The AD technology could manage the high salinity feed water with the production of low salinity water with a reasonable cost of US&#36;0.2/m3.

DOI： 10.1016/j.icheatmasstransfer.2021.105594

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Desiccant dehumidification systems can be utilized for decoupling moisture removal duty from the conventional mechanical vapor compression systems. Dehumidification using desiccant dehumidifiers is expected to exhibit a better energy efficiency. However, the high energy needed in the regeneration process limits its applicability. To realize the full potential of this technology, it is necessary to develop materials that can be regenerated using heat sources under 70 °C. In this study, activated carbons (ACs) derived from waste biomass were developed as desiccant materials. The ability of activated carbon (AC) to remove the moisture was controlled by carefully preparing the material to achieve the right operation window for optimum moisture sorption processes. The porous and surface characteristics of the newly-prepared AC were analyzed and compared with those of silica gel. The adsorption isotherm measurements were conducted, and the data were fitted with Henry–Sips and Do–Do isotherm models. The current ACs exhibit an excellent water adsorption capacity (up to 0.41 g/g). The efficacy of the ACs for dehumidification applications was assessed using the weather data from several regions of Indonesia, from North Sumatera to Papua. The results revealed that under the studied conditions, the new desiccant material showed a better dehumidification capacity than silica gel. Moreover, the reported AC can be regenerated using temperatures as low as 40 °C, which is readily available from waste heat, including the heat rejection from the condenser of an air-conditioning unit.

DOI： 10.1016/j.egyr.2021.09.003

記述言語：英語  

DOI： 10.18462/iir.HFO.2021.1023

記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Sustainable Energy  

This paper presents a comparative analysis of the potential working fluids for a promising thermodynamic cycle (Thermal Power Pump cycle) for the utilisation of low-grade heat. The cycle was analyzed along with nucleate boiling correlations and film condensation analysis for variable heat source temperatures (50–150°C) using nine potential working fluids. The working fluids showed varying degrees of cycle performance and system size requirements. Among the working fluids, cyclopentane seems to be an attractive choice of working fluid, due to its superior cycle performance over the wide range of heat source temperatures with moderate system size requirements. For temperatures above 146°C and below 60°C, water and n-pentane are selected, respectively. Working fluids with stronger molecular forces seem to approach the properties of an ideal working fluid for better performance of the system.

DOI： 10.1080/14786451.2021.1924717

Web of Science

Scopus

記述言語：その他   掲載種別：研究論文（学術雑誌）  

The energy consumption during the start-up and cabin pull-down operation of an air-conditioning system (A/C) for electric cars was studied in this work. An entire system model consisting of a CO2 vapor compression system (VCS), air handling unit (AHU), and the cabin was established utilizing an acausal, object-oriented, and equation-based modeling platform. A previously validated model was adopted for the VCS. AHU and cabin models were established by paying attention to the latent heat load, humidity, and dehumidification. The models were validated against the data from three different studies. A set of transient simulations was carried out for the start-up and cabin pull-down operation periods. It is found that the initial temperature of the cabin significantly influences the energy consumption and pull-down time. When the cabin target temperature decreases from 25 °C to 21 °C, the compressor consumes 58&#37; more energy, and the pull-down time increases by 23&#37;. Increasing the initial temperature 35 °C to 55 °C leads to 150&#37; longer pull-down time, and 289&#37; more energy consumption. The initial RH of the cabin air has a negligible impact on the pull-down time, but affects energy consumption. Increasing the RH from 33&#37; to 66&#37; results in 9&#37; energy consumption.

DOI： 10.1016/j.applthermaleng.2021.116825

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Low-temperature refrigeration (aka, deep-freezing) have an essential role in the food and pharmaceutical industries. Considering environmental and economic concerns, Carbon Dioxide (R744) has presented itself as a competent refrigerant. Even though many researchers performed extensive investigations on the performance of the low-temperature refrigeration cycles, the innovations in this field still exist, and refinement and examination of new layouts remain a hot topic, among which coupling an ejector with the cycle is a popular method that has shown promising results. This article proposes a new layout for low-temperature refrigeration together with the thermodynamic studies on the effects of changing pressures before and after the ejector by introducing an additional compressor, gas cooler, and turboexpander to the conventional layout of transcritical CO2 ejector cycle. The coefficient of performance (COP) around 1.4 was obtained for evaporation at −45 °C. The first law analysis of the cycle was conducted, and optimal values for pressures before and after the ejector were identified. It was found that using a compressor and a gas cooler before the secondary entrance of the ejector is beneficial to COP, and the expansion process right after the ejector will affect the COP. It was discovered that the instant expansion after ejector is unnecessary at optimum conditions, and the phase condition of the ejector's discharge has a huge impact on the performance. Optimization and parametric analysis of the cycle was conducted, and the effects of efficiencies of the cycle's components on COP were investigated. A simple and comprehensive second Law analysis of the proposed system is included, and the performance of the setup was briefly compared with other cycles in low-temperature refrigeration. It was revealed that this single-refrigerant proposed cycle not only can reach a reasonable performance for deep-freezing applications, but also it has 10&#37; less compression ratio than its R744 counterparts.

DOI： 10.1016/j.applthermaleng.2020.116531

記述言語：その他   掲載種別：研究論文（学術雑誌）  

R410a will remain a common refrigerant in developing nations, even though its high environmental impact assures its eventual phase out. In the hopes of tackling the afore mentioned and identifying potential areas of improvement, the performance of a 2.0 kW chiller is evaluated. The first law of thermodynamics highlights the disadvantage of overcharging the refrigerant amount and the second law applied through an exergy approach points to the compressor as the largest contributor to exergy destroyed and its effects on reducing condenser performance as well. This analysis can be directly compared with alternative refrigerants to replace R410a in the future.

DOI： 10.5109/4372281

記述言語：その他   掲載種別：研究論文（学術雑誌）  

In conventional ejector refrigeration cycles, the ejector mostly operates at fixed pressure points in the secondary stream and outlet. Studying the sensitivity of the system to the pressure alternation of the mentioned points has not been investigated. To cover this gap, an extra turboexpander, compressor, and gas cooler were introduced to the conventional ejector layout. It was found that pressurizing the secondary entrance of the ejector could be beneficial to COP if it is not warmer than the gas coolers. Also using the expansion process right after the ejector has the potential to increase the efficiency of the system if the discharge pressure of the ejector reaches supercritical or superheat condition.

DOI： 10.5109/4372280

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Adsorption cycles have been gaining significant interest in waste-heat recovery and renewable energy utilization. Adsorption isotherm data and the equilibrium cycle analysis are crucial steps in evaluating a typical adsorbent + adsorbate pair. In this paper, the performance of Maxsorb III + R245fa and spherical activated carbon, SAC-2 + R245fa were studied for adsorption cooling and adsorption heat transformer (AHT) cycles. Adsorption isotherms of these pairs were measured using the constant-volume-variable-pressure apparatus for temperatures ranging from 30 °C to 60 °C, and fitted with the Dubinin–Astakhov (D–A) and the Tóth isotherm model. An improved equilibrium model was developed, accounting the effects of thermal masses. The specific cooling energy (SCE) and the coefficient of performance (COP) of the adsorption cooling cycle were evaluated for various thermal mass to adsorbent mass ratios. It is observed that SAC-2 + R245fa pair offers better SCEs (20 kJ kg−1and 160 kJ kg−1 at 60 °C and 90 °C, respectively) when compared to that of Maxsorb III + R245fa. The impact of thermal mass is found to be significant for all regeneration temperatures for Maxsorb III + R245fa while the deterioration of COP in SAC-2 + R245fa is notable for high regeneration temperatures (> 75 °C). When employed in the AHT cycle, Maxsorb III offers a slightly higher useful heat while SAC-2 provides a better Quh/QQR albeit by a small margin. The Quh/QQR values for both studied pairs are more than 0.6 for all regeneration temperatures for the heat extraction at 120 °C.

DOI： 10.1016/j.ijrefrig.2020.12.005

記述言語：その他   掲載種別：研究論文（学術雑誌）  

This study explores evaporative cooling options for greenhouse air-conditioning for the climatic conditions of Multan (Pakistan). Greenhouse requires temperature and humidity control unit to optimize the environment inside the greenhouse for plants. In this regard, three low-cost lab-scale experimental evaporative cooling (EC) systems (i.e. direct EC (DEC), indirect EC (IEC), and Maisotsenko cycle EC (MEC)) were developed. The thermodynamic performance of the developed systems was analyzed from the viewpoints of the temperature gradient, relative humidity, vapor pressure deficit, and wet bulb, and dew point effectiveness. The MEC, DEC, and IEC systems created a temperature gradient of 18-21°C, 20-28°C, 27-31°C at ambient temperature 28-40°C for 15th May for the climatic conditions of Multan. The spatiotemporal evaluation of temperature, relative humidity, and vapor pressure deficit (VPD) revealed that plain areas of Pakistan including Punjab province received severe temperature peaks. Whereas relative humidity peaked in monsoon season across the plain areas. Whereas for VPD, plain areas of Pakistan faced severe peaks in the summer months which can be optimized using the MEC system for greenhouse air-conditioning. Thus, the results conclude the MEC system as an optimum air-conditioning option for greenhouse air-conditioning.

記述言語：その他   掲載種別：研究論文（学術雑誌）  

In this study, we evaluated the performance of low Global Warming Potential (GWP) refrigerant R1234yf on the activated carbon (MSC‐30) for adsorption heating applications. The ad-sorption isotherms of MSC‐30/R1234yf were measured using a constant‐volume–variable‐pressure (CVVP) method from very low relative pressure to the practical operating ranges. The data were fitted with several isotherm models using non‐linear curve fitting. An improved equilibrium model was employed to investigate the influence of dead thermal masses, i.e., the heat exchanger assembly and the non‐adsorbing part of the adsorbent. The model employed the model for the isosteric heat of adsorption where the adsorbed phase volume was accounted for. The performance of the heat pump was compared with MSC‐30/R134a pair using the data from the literature. The analysis cov-ered the desorption temperature ranging from 60 °C to 90 °C, with the evaporation temperature at 5 °C and the adsorption temperature and condensation temperature set to 30 °C. It was observed that the adsorption isotherms of R1234yf on MSC‐30 were relatively lower than those of R134a by approximately 12&#37;. The coefficient of performance (COP) of the selected pair was found to vary from 0.03 to 0.35 depending on the heat source temperature. We demonstrated that due to lower latent heat, MSC‐30/R1234yf pair exhibits slightly lower cycle performance compared to the MSC‐ 30/R134a pair. However, the widespread adaptation of environmentally friendly R1234yf in auto-mobile heat pump systems may call for the implementation of adsorption systems such as the direct hybridization using a single refrigerant. The isotherm and performance data presented in this work will be essential for such applications.

DOI： 10.3390/app11052279

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Poultry are one of the most vulnerable species of its kind once the temperature‐humidity nexus is explored. This is so because the broilers lack sweat glands as compared to humans and undergo panting process to mitigate their latent heat (moisture produced in the body) in the air. As a result, moisture production inside poultry house needs to be maintained to avoid any serious health and welfare complications. Several strategies such as compressor‐based air‐conditioning systems have been implemented worldwide to attenuate the heat stress in poultry, but these are not economical. Therefore, this study focuses on the development of low‐cost and environmentally friendly improved evaporative cooling systems (DEC, IEC, MEC) from the viewpoint of heat stress in poultry houses. Thermodynamic analysis of these systems was carried out for the climatic conditions of Multan, Pakistan. The results appreciably controlled the environmental conditions which showed that for the months of April, May, and June, the decrease in temperature by direct evapo-rative cooling (DEC), indirect evaporative cooling (IEC), and Maisotsenko‐Cycle evaporative cooling (MEC) systems is 7–10 °C, 5–6.5 °C, and 9.5–12 °C, respectively. In case of July, August, and September, the decrease in temperature by DEC, IEC, and MEC systems is 5.5–7 °C, 3.5–4.5 °C, and 7–7.5 °C, respectively. In addition, drop in temperature‐humidity index (THI) values by DEC, IEC, and MEC is 3.5–9 °C, 3–7 °C, and 5.5–10 °C, respectively for all months. Optimum temperature and relative humidity conditions are determined for poultry birds and thereby, systems’ performance is thermodynamically evaluated for poultry farms from the viewpoint of THI, temperature‐humid-ity‐velocity index (THVI), and thermal exposure time (ET). From the analysis, it is concluded that MEC system performed relatively better than others due to its ability of dew‐point cooling and achieved THI threshold limit with reasonable temperature and humidity indexes.

DOI： 10.3390/su13052836

記述言語：その他   掲載種別：研究論文（学術雑誌）  

This study presents the attempt made to develop an ideal equivalent system for adiabatic expansion type thermal pumps found in the literature. The purpose of developing the ideal system is to investigate the maximum achievable performance of such systems irrespective of the system sizing and pump design adopted and obtain a characteristic efficiency. An ideal system was developed and analyzed. Then the system performance was compared with literature data, which was found to be reasonable. The comparison of the ideal performance of such systems with existing cycles revealed that the efficiency of such types of pumping systems is limited.

DOI： 10.5109/4372284

記述言語：その他   掲載種別：研究論文（学術雑誌）  

The green preparation of microporous activated carbon using acorn nutshell with different production conditions was studied. The heating rate and nitrogen flow rate were controlled during preparation. The effect of those conditions on the surface properties and water adsorption performance was observed. According to the results, the total surface area of acorn nutshells-based activated carbon can reach up to 993 m2/g with 90&#37; microporosity and a total pore volume of 0.49 cm3/g. The water adsorption uptake under P/P0 = 0.9 of prepared material is up to 0.39 g/g. This study found that acorn nutshell shows potential performance as a precursor for producing highly microporous activated carbon, which might be suitable for water vapor adsorption.

DOI： 10.5109/4372285

記述言語：その他   掲載種別：研究論文（学術雑誌）  

The lubricant, which is considered as the necessary part inside the compressor, not only affects the operating efficiency of the compressor but also has interaction with refrigerant. To study the effect of lubricants on the improvement of heat pump performance, this paper investigated the types and the viscosities of lubricants that are chosen to apply in the heat pump cycle. The influence of lubricants was explained from three aspects: the interaction with refrigerants, the effect on the compressor, and the impact on the system performance, which may make some contribution to the development of new lubricant oils.

DOI： 10.5109/4372279

記述言語：その他   掲載種別：研究論文（学術雑誌）  

This research work reports on the potential of bagasse, a solid waste from sugar factories, to produce activated-carbon (AC) as an adsorbent. The activation was conducted under 500, 600, and 700◦ C using steam as the activation agent to produce AC500, AC600, and AC700, respectively. The prepared-materials were characterized to understand their elemental content, surface morphology, thermal properties, functional groups identification, surface area, and pore size. AC700 provided the highest surface area of 592.36 m2 /g and indicated the contribution of mesopores distributes along 1.5–8.0 nm of pore size. Therefore, an adsorption test was conducted with AC700 as adsorbent. The results show that methylene blue (MB) adsorption reached equilibrium after 30 min of adsorption time. The adsorption isotherm applied to a monolayer Langmuir isotherm was fitted by linearization, resulting in a constant R2 of 0.999. The MB adsorption to AC700 favorably occurred, as proven by the Freundlich parameter 1/n of 0.881, which is less than 1. The Dubinin-Radushkevich isotherm confirmed that the adsorption proceeded through physical interaction with adsorption energy of 3.536 kJ/mol.

DOI： 10.3390/app11020678

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Domestic heat pumps constitute a significant part of the global heat pump industry. R401A offers excellent performance with no influence on the ozone depletion and has been a dominant refrigerant in most domestic heat pumps. However, R410A has a significant impact on the climate due to its high global warming potential (GWP). Thus, the heat pump industry has been focusing on the development of R410A substitutes. Pure refrigerant alternates, such as HFC32, and the blends mixed with low-GWP refrigerants, such as HFO1234yf and HFO1234ze(E), are widely reported. Besides the direct impact of refrigerants (which is estimated as GWP), domestic heat pumps indirectly affect the environment from the energy consumption and manufacturing processes. Hence the life cycle climate performance (LCCP) analysis accounts for all emissions through the lifetime of a heat pump. This article reports the LCCP evaluation of various low-GWP refrigerants for R410A replacement on domestic heat pumps. Six refrigerants, i.e., HFC32, binary blends of HFC32 and HFO1234yf (with GWP values of 300, 200 and 150), and HFC32 and HFO1234ze(E) with GWP values of 300 and 200, were compared against R410A. The performance data of these refrigerants from the experimental heat pump facility were utilized to evaluate the LCCP. Among the selected refrigerants, the binary blend of HFC32/HFO1234ze(E) with GWP 300 shows the lowest LCCP. Low-GWP refrigerants would become more competitive than R410A when CO2 emission from energy generations can be reduced by the optimization of the system or the usage of renewable energy.

DOI： 10.1016/j.ijrefrig.2020.09.020

記述言語：その他   掲載種別：研究論文（学術雑誌）  

In this study water adsorption onto silica gel are experimentally measured and isotherm data successfully correlated with Guggenheim-Anderson-de Boer (GAB) model. The Silica gel/water pair is compared with four different adsorbent-refrigerant pairs from the literature (i.e. KOH activated phenol resin based activated carbon (KOH6-PR)/ethanol pair, activated carbon (Maxsorb III)/methanol pair, zeolite (AQSOA-Z02)/water pair and polymer (PS-II)/water pair. The cooling performance parameters like specific cooling energy (SCE) and coefficient of performance (COP) of ideal adsorption cooling cycle employing each pair are evaluated by using a time independent thermodynamic model. The Dühring (i.e. P-T-W) diagram containing the ideal cycle operative at evaporator and regeneration temperatures of 10 °C and 80 °C, respectively, is constructed. Also, ideal cycle performances of adsorption system are evaluated for the evaporator temperatures of 5°C and 10°C while having the regeneration temperatures range of 55°C to 80°C. It is found that among the selected adsorbents-refrigerant pairs Maxsorb III /methanol pair has the maximum SCE and COP, at 10°C evaporator temperature, of 898.19 kJ/kg and 0.807 respectively. While minimum SCE and COP is attributed to silica gel/water pair.

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Refrigeration and air-conditioning systems become an integral part of modern society. Electricity-driven vapour compression systems have been dominating the heating, ventilation, air conditioning and refrigeration (HVAC&R) industry. The working fluids of these systems often contribute to the environmental issues in the forms of direct and indirection emissions. Pure refrigerants are often limited in meeting criteria such as efficiency, flammability, toxicity, and compatibility. Meanwhile, refrigerant mixtures offer flexibilities to tune these criteria, and the reusability of the existing hardware is often a priority in practice. We evaluated a binary mixture of HFC32 and HFO1234yf with a target global warming potential (GWP) under 150 for domestic heat pumps. Drop-in tests were conducted for two modes; Heating#1 and Heating#2 at different condensing temperatures. The performance of the current binary refrigerant was compared with those of target refrigerants, i.e., R410A, HFC32 and the binary mixture of HFC32/HFO1234yf (22/78 mass&#37;, GWP = ~300) for part- and full-load operations. Experimental results showed that the performance of the present refrigerant is comparable with R410A and HFC32 for high condensing temperatures, especially at part-load operations. The system COP of the current binary blend exhibits from 6 to 14&#37; drop as compared to that of R410A. A significant increase in the system irreversibility losses was observed with the increasing percentage of HFO1234yf. Despite the relatively low performance, the GWP of the present refrigerant is below 150, and it can be used in the existing systems without significant hardware changes while meeting tighter environmental regulations.

DOI： 10.1016/j.applthermaleng.2020.115952

記述言語：その他   掲載種別：研究論文（学術雑誌）  

A high-pressure lift often triggers an increased power input to the vapor compression systems. The increased power consumption becomes a bottleneck in R-744 refrigeration systems for freezing and refrigeration applications. Meanwhile, phase change materials (PCM) offer operation flexibility in the form of the compressor run-time from the energy storage potential. In this article, the energy-saving potential of the PCMs on a cascade refrigeration system using CO2 is investigated focusing on the impacts of charge amounts and the thermal resistance of the PCM. The validated dynamic model in Simscape™/MATLAB for an R-744 vapor compression system is adopted for a cascade refrigeration system together with the validated PCM model. In the studied system, the PCM is installed in the storage compartment as a thermal buffer. The comprehensive model employed an acausal, object-oriented, and equation-based paradigm adopting detailed heat transfer characteristics. The effect of PCM on the compressor running time was investigated under the cyclic steady-state operating conditions. The results showed that the compressor “On-time” ratio decreases when using the PCM; subsequently, the power reduction. The system consumes about 6.76 kWh (without PCM) and 5.93 kWh with PCM; thus, the power consumption decreases by 12.3&#37;. The threshold PCM charge ratio is observed to be 1. Increasing the PCM charge value above this threshold does not trigger a significant decrease in power reduction. The increase in the overall thermal resistance of PCM has a negative impact on the “On-time” ratio and power consumption. The benefit of PCM is insignificant for thermal resistance above 0.02 K W−1. Despite the shortcomings of several assumptions involved, the present results clearly highlight the positive impacts of the PCM in terms of power savings for low-temperature refrigeration applications using R-744.

DOI： 10.1016/j.applthermaleng.2020.116104

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Research trends in the heat pump systems can mainly be categorized into the developments of the cycle and the working fluids. Regional and global watchdogs regulate the fate of working fluids in the name of environmental issues, especially global warming. Examples include the Montreal Protocol, the Kyoto protocol, and lately, the European “F Gas” Directive (No. 542/2006). The urgent and pressing call is next-generation refrigerants that are benign to the environment without compromising the performance. Pure substances are known to be limited, while refrigerant mixtures have been gaining significant attention due to their flexibility in tuning flammability, stability, and low GWP values. In this work, we investigated a ternary mixture of HFC-32/HFO-1234yf/R744 (22/72/6mass&#37;) with the targeted GWP less than 150. Three operation modes (cooling for summer, Cooling, low-temperature heating, Heating#1, and high-temperature heating, Heating#2 for winter) were investigated experimentally. Optimal refrigerant charge amounts for all operation modes followed by the system performance were evaluated from part-load to full-load operations. The system is further scrutinized using the 2nd Law of Thermodynamics by tracking exergy destructions in major components. Among the selected operation modes, Heating#1 provides the highest system COPs for all loads due to the lower lift and smaller temperature difference between the inlet and outlet of the coolant to the condenser. The cycle exergetic efficiencies were 31.7&#37;, 37.8&#37;, and 43.3&#37; for Cooling, Heating#1, and Heating#2 modes, respectively. The results presented in this work will be useful in the refrigerant design (ternary mixtures) and the system development for low-GWP refrigerant applications.

DOI： 10.1016/j.ijrefrig.2020.10.009

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Adsorption thermal energy storage plays a vital role in supporting the availability of renewable energy. Activated carbons produced from local waste biomass have been attracting considerable attention in adsorption technology due to their unique properties and sustainability. However, their limitation in water vapor uptake hinders the practical application of this material. In this work, acorn nutshells were utilized as a base material to produce activated carbon. Air oxidation was performed as a versatile and low-cost technique to enhance the material's properties and water adsorption capacity. By applying air oxidation as a post-treatment during material production, the amount of active functional groups and the water adsorption on activated carbon has been successfully enhanced. From the theoretical calculation, it is found that activated carbon–water working pairs shown promising performance to be used for adsorption thermal energy storage applications. The adsorption of water vapor on the post-treated-activated carbon releases the isosteric heat between 2400 kJ/kg to 2500 kJ/kg. Moreover, this study's working pair can be driven by a temperature of less than 50 °C. From the results, it is confirmed that by controlling the adsorbent's surface properties, activated carbon–water working pairs can be a promising way to provide alternative material and reduce the energy demand for driving the system.

DOI： 10.1016/j.egyr.2020.11.038

記述言語：その他   掲載種別：研究論文（学術雑誌）  

This study reports on the investigation of the performance of single and two-stage liquid and solid desiccant dehumidification systems and two-stage combined liquid and solid desiccant dehumidification systems with reference to humid climates. The research focus is on a dehumidification system capacity of 25 kW designed for room air conditioning application using the thermal models reported in the literature. RD-type silica gel and LiCl are used as solid and liquid desiccant materials, respectively. In this study, the application of proposed system for deep drying application is also explored. Condensation rate and moisture removal efficiency are chosen as performance parameters for room air conditioning application, whereas air outlet temperature is chosen as performance parameter for deep drying application. Further, for a given range of operating parameters, influences of air inlet humidity ratio, flow rate, and inlet temperature on performance parameters of the systems are investigated. In humid climatic conditions, it has been observed that a two-stage liquid desiccant dehumidification system is more effective for room air conditioning application, and two-stage solid desiccant dehumidification system is more suitable for deep drying application in the temperature range of 50 to 70◦ C, while single-stage solid desiccant and two-stage combined liquid and solid desiccant dehumidification systems are more effective for low temperature, i.e., 30 to 50◦ C deep drying application.

DOI： 10.3390/su122410582

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A hybrid method with a microfin tube and TiO2/water nanofluid with various nanoparticles concentration has been investigated experimentally. The objectives of this work arc to characterize thermohydraulic including friction factor and thermal performance, and to develop correlation based on the experimental result. In general, adding nanopartides to the base fluid causes increased thermal performance. Pressure drop inside the microfin tube at TiO2/water concentrations of 0.05, 0.15, and 0.30 vol&#37; were respectively 73&#37;, 77&#37;, and 80&#37; higher than that in the smooth tube. Furthermore, the pressure drop increased with an increment in Re number. In this work, the developed correlation was proposed to predict practically Nu number. The present findings contribute to our understanding of how to enhance heat transfer using helical microfins inside tubes and nanofluids. (C) 2020 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.powtec.2020.08.020

記述言語：その他   掲載種別：研究論文（学術雑誌）  

A hybrid method with a microfin tube and TiO2/water nanofluid with various nanoparticles concentration has been investigated experimentally. The objectives of this work are to characterize thermohydraulic including friction factor and thermal performance, and to develop correlation based on the experimental result. In general, adding nanoparticles to the base fluid causes increased thermal performance. Pressure drop inside the microfin tube at TiO2/water concentrations of 0.05, 0.15, and 0.30 vol&#37; were respectively 73&#37;, 77&#37;, and 80&#37; higher than that in the smooth tube. Furthermore, the pressure drop increased with an increment in Re number. In this work, the developed correlation was proposed to predict practically Nu number. The present findings contribute to our understanding of how to enhance heat transfer using helical microfins inside tubes and nanofluids.

DOI： 10.1016/j.powtec.2020.08.020

記述言語：その他   掲載種別：研究論文（その他学術会議資料等）  

The increase in global energy demand, the scarcity of fossil fuels resources, climate change and global warming are undeniable realities. In this energy context, the implementation of concrete measures in favor of greater energy efficiency systems becomes urgent. Among these systems, the integration of environmental friendly, low energy adsorption technologies is gaining more interest in many chemical, residential and industrial applications such as adsorption refrigeration systems, quality treatment and energy storage processes. Pressure swing adsorption and temperature swing adsorption are among the promising techniques for CO2 capturing and separation from exhaust gases. In this study, corrected adsorption rates of CO2 onto activated carbon powder were investigated using computational fluid dynamics simulation. The modified linear driving force (mLDF) model was used as the adsorption kinetics equation by fitting of experimental data with isothermal assumption. Then the adsorbent layer temperature was estimated with CFD simulation which allowed to adjust the diffusion time constants for accurate performance investigation of CO2 adsorption cooling, storage and separation applications.

DOI： 10.1007/978-3-030-52071-7_26

記述言語：その他   掲載種別：研究論文（学術雑誌）  

A new model of adsorption isotherms Type IV and V is proposed as a basis for theoretical calculations and modelling of adsorption systems such as adsorption heat storage and heat pumps. As the current models have decent yet limited applicability, in this work, we present a new combined model with universal use for micro-mesoporous silica/water adsorption systems. Experimental measurement of adsorption isotherm of water onto seven different samples of micro and mesoporous silica and aluminium-silica were used to fit new adsorption models based on a combination of classical theories and a distribution function related to the pore-size distribution of the selected materials. The fitting was conducted through a repeated non-linear regression using Trust Region Reflective algorithm with weighting factors to compensate for the scalability of the adsorption amount at low relative pressure with optimization of the absolute average deviation fitting parameter. The results display a significant improvement for most of the samples and fitting indicators compared to more common models from the literature with average absolute deviation as low as AAD = 0.0025 g g for material with maximum uptake of q = 0.38 g g . The newly suggested model, which is based on a combination of BET theory and adjusted normal distribution function, proved to bring a higher degree of precision and universality for mesoporous silica materials with different levels of hydrophilicity. − 1 − 1

DOI： 10.3390/en13164247

記述言語：その他   掲載種別：研究論文（学術雑誌）  

Countermeasures for global warming have been promoted internationally. Heat pump cycles that utilize refrigerants with high global warming potential values are required to adopt the next generation refrigerants to conform to the revised Montreal Protocol. Refrigerants R410A is commonly used in the room air conditioners while it has been substituted with HFC32 in Japan; yet their global warming potential values are relatively high and are going to be phased down in the near future. On the other hand, refrigerant mixtures such as the blend of HFC32 and HFO1234yf with extremely low global warming potential can be considered as possible alternatives in compromising the flammability and the ecological tribulations. Targeting the global warming potential value of 150 or lower, the performance of HFC32/HFO1234yf (22/78 mass&#37;) blend was evaluated using drop-in tests, and the results were compared with those of R410A and HFC32. Optimum charge amounts for these refrigerants were first evaluated, followed by the performance comparison in terms of the coefficient of performance from part- to full-load operations. The results showed that the current blend with the low global warming potential less than 150 is comparable to the targeted substitutes at part-load operations while within 83–87&#37; of the COP using HFC32 was achievable at the full-load. The performance results from these experiments could serve as the basis for the refrigerant evaluation targeting the global warming potential 150.

DOI： 10.1080/01457632.2020.1776997

記述言語：その他   掲載種別：研究論文（学術雑誌）  

The objective of the present manuscript is to develop a dynamic model to simulate the transient performance of a heat pump system that utilizes environmental-friendly refrigerant, Carbon Dioxide (R-744). Exploiting the high customizability of the modeling tools supporting acausal, equation-based, and object-oriented modeling approach, a dynamic model for a transcritical heat pump system was developed. The model was validated with the experimental results with particular attention to the refrigerant mass flow rate, cooling/heating capacity, compressor power, and the coefficient of performance.

記述言語：その他   掲載種別：研究論文（学術雑誌）  

The urge to replace hydrofluorocarbons which possess high global warming potentials has taken center stage in the air conditioning industry due to both international and local policies such as the Kigali Amendment and Japan’s revised Fluorinated Gas law. This has prompted the exploration of novel refrigerants as well as their mixtures to create high performance environmentally friendly alternatives. These refrigerants can be integrated into existing systems as ‘drop in’ refrigerants, which provide a simpler and low cost substitution process to replace environmentally harmful refrigerants such as R410a. R410a is currently a widely used refrigerant in air conditioning systems, but is to be phased out of use under the Kigali Amendment by the late 2040s. Thus to compare the suitability of replacing this refrigerant with environmentally friendly ‘drop in’ alternatives, a preliminary baseline investigation on a mechanical vapor compression chiller with R410a is conducted via performance and exergy indicators. The testing procedure utilized Air Conditioning, Heating and Refrigeration Standard 551/591 which revealed an optimum charge amount of 0.70 kg with a peak performance near 88&#37; of full capacity. The heat exchanger overall heat transfer coefficients showed varying trends, whilst the exergy destruction was as expected highest for the compressor.

DOI： 10.1080/01457632.2020.1776990

記述言語：英語   掲載種別：研究論文（学術雑誌）  

After publishing an article in which the impact of wing-width ratio of double-sided delta-wing tape (T-W) inserts on thermal-hydraulic performance [Wijayanta et al., Appl. Therm. Eng. 145 (2018) 27–37] were investigated, we have extended our work to modified enhanced heat transfer area design for wing-pitch ratio (P/W) acting on the geometric features of delta-wing tape inserts. There are a limited number of studies in this area regarding the wing-pitch ratio. In the current study, T-W inserts with P/W of 1.18, 1.47, and 1.65 were manufactured and evaluated to improve single-phase convective heat transfer, under the conditions of a Reynolds number between 5,300 and 14,500, with water used as the working fluid. T-W inserts with a P/W of 1.18 offer the highest average Nusselt number, with an increase of approximately 177&#37; compared to a plain tube. However, the friction factor is 11.6 times greater compared to a plain tube, showing that the friction loss is more significant with T-W inserts. In addition, T-W inserts with a P/W of 1.18 produce the greatest thermal performance factor of 1.15. Generally, Nusselt number, friction factor, and thermal performance factor of the heat exchanger increase following the decrease of P/W of the T-W inserts. In this study, the empirical correlations have been modeled using the obtained experimental data.

DOI： 10.1016/j.ijthermalsci.2020.106261

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The inverted Brayton cycle can be applied to exploit the exergy content of the waste heat. The cycle can be operational at low heat source temperatures, and it is particularly suitable for recovering the low-temperature waste heat. Being low temperature-driven, the thermal efficiency of such an inverted Brayton cycle is considerably low. In this study, an attempt has been made to improve the performance of the cycle by hybridizing with an indirect evaporative cooling (IEC) device. A counter-flow type indirect evaporative cooler is introduced to the inverted Brayton cycle to condition the working fluid prior to the compressor inlet. Detailed numerical models for both cycles were developed and validated with the experimental data of Riangvilaikul and Kumar for a counter flow IEC. The performance of the present configuration is compared with various methods of cooling the working fluid such as the conventional air cooling and a recuperator. The proposed cycle exhibits a significant improvement in terms of the specific work output (45&#37;) for all turbine inlet temperatures regardless of the inlet air conditions, while a higher thermal efficiency can be realized for low-temperature heat source below 85 °C.

DOI： 10.1016/j.applthermaleng.2020.115029

記述言語：英語  

Adsorption cooling is getting huge attention from last few years due to environment-friendly and thermally-driven technology. Many systems designs based on various adsorbent-adsorbate pairs are investigated worldwide to develop a cost-effective and high-performance system. Until now, performance of the systems is lower as compared to conventional compressor-based systems. Performance of the adsorption systems mainly depends on adsorption equilibrium, adsorption kinetics, isosteric heat of adsorption, and thermo-physical/chemical properties of assorted adsorbent-refrigerant pairs. Thereby, the present study aims to review and compare the physical properties (surface area, pore volume/size etc.) of adsorbents and adsorption equilibrium (adsorption isotherm) by various types of adsorbent-adsorbate pairs available in the literature. Amount of adsorbate adsorbed per unit mass of adsorbent has been critically reviewed and compared accordingly. Highest adsorption uptake was attributed in case of R-32 adsorption onto phenol resin-based activated carbon i.e. 2.23 kg/kg (excess adsorption) and 2.34 kg/kg (absolute adsorption) at 30 °C and 1670 kPa. Activated carbon of type Maxsorb-III being highly microporous possesses high surface area and shows good adsorption uptakes for most of the adsorbates including ethanol, methanol R-134a, CO₂, R-507A and n-butane. In addition, fundamentals, principle and features of adsorption cooling systems are discussed. Adsorption equilibrium models used to express the adsorption mechanics of adsorbent-adsorbate pairs are explored, and the models’ parameters are collectively listed and discussed. The review is useful to prioritize available adsorbent-adsorbate pairs for adsorption based heat transformation applications. The study is useful for researchers working for the development of adsorbent materials for various applications and conditions.

DOI： 10.1016/j.rser.2019.109630

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Demands of standalone dehumidification systems have been increasing in order to realize energy savings in air-conditioning processes. In a desiccant dehumidification system, the water vapor from the moist air undergoes a phase change phenomenon, this being from vapor to adsorbed phase, a process analogous to latent heat exchange. The energy exchange involved in such a process is often significant-up to 80&#37; of the total energy exchange. In this study, the influence of the phase change phenomena involved in a desiccant dehumidification system was evaluated experimentally, along with the performance investigation under low desorption air temperatures of 308, 318, 328, 338, and 345 K. The system was driven by a constant adsorption temperature of 293 K. The dehumidification ability, latent heat ratio, and latent effectiveness were employed as key performance indexes. The results showed that with the increased desorption temperature, the latent heat ratio decreased, whereas the dehumidification ability and latent effectiveness increased. The highest latent heat ratio was found to be 0.61 at the desorption temperature of 308 K, whereas the highest latent effectiveness was obtained at the desorption temperature of 345 K. A suitable temperature for the effective and efficient dehumidification was observed to be 318 K for the current system.

DOI： 10.3390/app10030868

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A detailed investigation on the main characteristics was conducted on a novel and unique group of industrially produced mesoporous silica material. Six materials from a TMPS group were selected in the respect to their pore size ranging from 1.8 nm up to 4.2 nm. Four of the selected samples were also made with silica doping making them potentially attractive for water adsorption applications with the advantage of the pore-tuning possibilities for specific use. The surface area, pore volume and pore size distribution of these materials were established by standard nitrogen adsorption at T = 77.4 K showing typical values of mesoporous silica materials such as high surface area in the range from 600 to 750 m²g⁻¹ and pore volumes reaching 0.38 cm³g⁻¹ in the case of the smallest TMPS-1.5A and 0.98 cm³g⁻¹ in the case of the largest TMPS-4R. The wall thickness was found out regular around 1.5 ~ 2 nm with lower values attributed to bigger pore sized samples promising good structural integrity. Specific heat showed regular values through all the samples at ~ 0.85 J g⁻¹K⁻¹. Additional information on the structural characteristics and the effect on the amount of silanol group presence and the difference on regular and aluminium-doped samples were studied by means of ²⁹Si DD/MAS NMR. Additionally, elemental analysis by EDS was conducted as well. All the characteristics of the TMPS materials were compared to the standard mesoporous silica materials SBA-15 and MCM-41.

DOI： 10.1016/j.micromeso.2019.109644

記述言語：英語  

Carbon-based materials have shown huge potential in various adsorption based applications e.g. water and wastewater treatment. In addition, these are successfully utilized for various (methanol-, ethanol-, and ammonia-based) closed-cycle adsorption heat pump systems. Significance of polymers is also well-known in drug/medical industry, and therefore extensively studied for various aspects of adsorption. The study comprises two kinds of polymer and carbon- based materials for potential air-conditioning applications. Water vapor adsorption comparison has been made among polymer, carbon-based and conventional hydrophilic adsorbent i.e. silica-gel. The size of desiccant unit in desiccant air-conditioning (DAC) system has been determined and compared accordingly. Results showed that polymer sorbent (PS-II) can reduce the desiccant unit size (in the DAC system) by 2-3 times as compare to conventional silica-gel under particular conditions while utilizing it intelligently.

記述言語：その他   掲載種別：研究論文（学術雑誌）  

The performance of an adsorption system using Maxsorb III + ethanol pair is investigated for practical heat pump applications. An adsorption system using a single bed with a single evaporator/condenser is employed and the performance of the system is assessed for various regeneration temperatures (80 °C, 70 °C and 60 °C). The impact of the adsorption time on the performance of the selected pair is further evaluated. The potential application of the present adsorbent + adsorbate pair is the automobile air-conditioning system where the exhaust waste heat will be recovered to operate the adsorption system. Thus, antifreeze fluid is employed as the heat transfer medium for the adsorber and the evaporator/condenser heat exchanger. A mathematical model is developed to estimate the uptake amount from the experimental data. The sensible heat change (thermal mass), the superheating of the refrigerant in the adsorber, the adsorber heat leak and the heat rejection to the heat transfer medium are accounted for. The uptake amount is further verified using the classical p–T–q diagram. For operation using 30 °C adsorber coolant inlet and 15 °C chilled water inlet, the cooling capacity of the present system ranges from 15 to 35 W for the adsorption times of 600 s and 300 s, respectively. It is observed that the regeneration temperature significantly influences the net uptake of the system. The maximum net uptake is recorded to be about 0.995 kg/kg for the regeneration temperature of 80 °C. The system is further assessed using the ratio of the cooling capacity to the adsorption heat.

DOI： 10.1016/j.ijrefrig.2018.06.009

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A combination of two passive heat transfer enhancement techniques using a microfin structure and nanofluids was investigated numerically. TiO₂/water nanofluids flowing inside a square minichannel with a microfin structure (SMM) were observed as a practical application. Increased heat transfer performance was investigated by observing the Nusselt number, friction factor, and performance evaluation criterion (PEC). Velocity and temperature profiles were also demonstrated at a laminar developing flow regime. The SMM used in this work had six microfins (N = 6) and TiO₂/water nanofluids with various nanoparticle concentrations of 0.005, 0.01, and 0.1 vol.&#37;. By combining nanofluids as working fluids and SMM as a passive heat transfer enhancement, the maximum PEC value of 1.2 was achieved at Re = 380 with a volume fraction of 0.01 vol.&#37;. It is obvious that compared to water flowing inside the square minichannel microfin, the heat transfer can be increased by using only a nanofluid with a volume fraction of 0.01&#37;. The combination of a microfin and nanofluids as working fluids is strongly recommended due to its excellent performance in terms of heat transfer and economic considerations.

DOI： 10.3390/en12163041

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Six samples from the TMPS family of mesoporous silica nano-materials from Taiyo Kagaku Co., Ltd. were studied for their potential as a medium for the adsorption thermal energy storage. Selected specimens are distinguished by their pore size from 1.9 to 4.1 nm and aluminium doping. As the adsorbate for the adsorption pair was selected water with the most advantageous properties of high latent heat and safe chemical properties. The tested materials doped with aluminium show high affinity towards the selected adsorbate and high uptakes. The theoretical storage energy density of the materials spans from 700 to 1700 kJ kg⁻¹ based on the adsorption heat. The storage capacity depends mostly on the pore volume and partially on the pore size. The theoretical estimation shows the temperature gain of the adsorption potential as high as ΔT=23∘C for the material TMPS-1.5A with the smallest pore diameter and aluminium doping and as low as ΔT=6∘C for the TMPS-4R with the biggest pore diameter and without aluminium doping.

DOI： 10.1007/s10450-019-00107-4

記述言語：英語  

DOI： 10.3390/app9112385

記述言語：その他   掲載種別：研究論文（その他学術会議資料等）  

Nowadays nanofluids are widely used for heat transfer enhancement. Nanometer-sized particles added to base fluid enhance the thermal conductivity and thus increase the heat transfer rate. In the present study TiO nanoparticle with the average diameter, 21 nm is used. Titanium dioxide (TiO ) nanofluid prepared by dispersing nanoparticles in distilled water using the two- step method with volume concentration (0.05&#37; - 0.3&#37;), has been investigated. The force convective heat transfer coefficient and friction factor of the TiO /Distilled water nanofluid with different volume concentration and Reynolds number for flow in a counterflow double tube heat exchanger are studied in this research. The result shows that the convective heat transfer coefficient of nanofluid is higher than base fluid for the same mass flow rate and same inlet temperature of nanofluid. The Nusselt number increases with Reynolds number and volume concentration TiO /Distilled water of nanofluid. Meanwhile, micro-fin tube increases pressure drop in the flow path. 2 2 2 2

DOI： 10.1063/1.5098218

記述言語：英語  

Effective thermal conductivity (ETC) of the adsorbent is an important parameter which influences the performance of the adsorption heat pump and adsorption cooling systems. Most of the adsorbents are porous in nature and therefore adsorption uptake is affected due to different operating conditions i.e. temperature and relative humidity (RH) that result in different ETC. Effect of temperature on ETC is somehow well-known in the literature, however, studies on RH effect are limited. Therefore, present study experimentally investigates the RH effect on the thermal conductivity of the commercially available zeolite-based adsorbents which are traded as: AQSOA-Z02 (zeolite-1) and AQSOA-Z05 (zeolite-2). The study is useful for the researcher who are working in the field of adsorption cooling, air-conditioning and desalination. In this regard, an experimental setup was developed by which the ETC was measured at different levels of RH. According to the results, the ETC of oven dried zeolite-1 and zeolite-2 was 0.060 W m⁻¹ K⁻¹ and 0.066 W m⁻¹ K⁻¹, respectively. With the increase in RH, the value of ETC increases up to 0.090 W m⁻¹ K⁻¹ for zeolite-1 and 0.089 W m⁻¹ K⁻¹ for zeolite-2. Moreover, an empirical relation is proposed which can estimate ETC at different levels of RH for both adsorbents.

DOI： 10.1016/j.applthermaleng.2018.12.144

記述言語：英語  

The ideal storage zones of dried fruits in comparison with dried foods and feeds are established on the psychrometric chart. The study investigates the combined effect of the desiccant dehumidification and Maisotsenko-Cycle evaporative cooling for the dried fruits storage. Two configurations of desiccant air-conditioning systems (S-I and S-II) are proposed, and their performance is evaluated under the ambient conditions of Fukuoka, Japan. It is established on the basis of parametric and thermodynamic analysis of both the system configurations (S-I and S-II) that S-II could yield better system performance. The psychrometric evaluation of S-II revealed that it can provide the optimal conditions for the storage of dried fruits at low regeneration temperature. However, modification in the proposed system configuration (S-II) is suggested for the storage of dried foods and feeds. Practical application: Conventional dehumidification and air-conditioning options are either expensive or inefficient for dried fruit storage buildings. The study provides a way forward of using thermally driven desiccant systems which are energy-efficient and environment-friendly. Worldwide, the building industries are actively involved in the development of such systems but their application for dried fruit storage buildings are not explored in detail. Therefore, the study provides thermodynamic details of dried fruits storage in relation with experimental evaluation of desiccant and evaporative cooling systems. Provision of such systems to the storage buildings will provide distinct control of humidity and temperature for optimal storage.

DOI： 10.1177/0143624419893660

記述言語：英語  

This study experimentally investigates desiccant dehumidification and indirect evaporative cooling for agricultural products' storage. Thermodynamic advantages of the proposed system are highlighted and compared to vapor compression systems. Significance of proposed system is discussed in relation to agricultural storage application. Factors affecting the postharvest quality of products are discussed, and consequently, the psychrometric zones are established for optimum storage. Hydrophilic polymeric sorbent-based desiccant units are used for the experimental investigation. An open-cycle experimental apparatus is setup by which desiccant dehumidification and regeneration processes are analyzed at various conditions. Thereby, a novel correlation is developed by which desiccant dehumidification process can be simulated precisely. The correlation is successfully validated against the experimental data of various conditions. Desiccant air-conditioning cycle is analyzed for two cases (i.e. case-A: dry-bulb temperature = 31 ℃, humidity-ratio = 6 g/kg-DA; and case-B: dry-bulb temperature = 13 ℃, humidity-ratio = 6 g/kg-DA) to investigate the proposed system's applicability for agricultural storage. The results show that the thermal coefficient of performance is highly influenced by ambient air conditions and decreases with the increase in regeneration temperature. The thermal coefficient of performance for case-A is higher as compared to case-B, and for both cases, it increases with the increase in wet-bulb effectiveness of the evaporative cooling unit.

DOI： 10.1177/0957650919869503

記述言語：英語  

The agricultural products are perishable in nature and possesses short shelf/storage life under ambient conditions. The temperature and humidity control systems are required to enhance to storage life of the products with optimum quality, quantity and nutritive attributes. In this regard, the significance of air-conditioning in storage application is highlighted along with the conventional storage options. The implications of compressor-based refrigeration and air-conditioning systems regarding low-cost and energy efficient air-conditioning systems are discussed in detailed. It is concluded that thermally driven air-conditioning systems can be used on top priority for the short-term storage of fresh agricultural products. Moreover, the long-term storage of products at freezing temperature can be made through hybrid systems instead of standalone conventional compressor based vapor compression refrigeration and/or air-conditioning systems. Finally, the air-conditioning systems are proposed for the optimum storage of different categorize of the food products.

DOI： 10.1515/ijfe-2019-0063

記述言語：英語  

The study investigates the applicability of solid desiccant system for drying of freshly harvested wheat grains in order to reduce the moisture to an optimum level. Fast and low-temperature drying systems are required by today’s drying industries in order to provide economical and safe drying. Therefore, comparison of desiccant drying has been made with the conventional method in terms of drying kinetics, allowable time for safe storage, the total time for drying cycle, and overall energy consumption. It has been found that the air conditions of proposed desiccant drying system provides a high drying rate and longer allowable storage time for the safe drying. As the desiccants possess water adsorbing ability by means of vapor pressure deficit, therefore, the desiccant system successfully provides low-temperature drying which ensures the quality of wheat grains. Overall energy consumption is estimated for both conventional hot air drying and desiccant drying system. It has been found that the desiccant system requires less energy as drying is accomplished at minimum level of air flow and within allowable storage time. In addition, the overall performance index of the desiccant system is higher at all temperatures. The study is useful for developing a low-cost and sustainable drying technology for various agricultural products.

DOI： 10.25165/j.ijabe.20191201.3854

記述言語：英語  

Adsorption and desorption of difluoromethane (HFC-32) onto newly developed phenol resin based adsorbent (SAC-2) have been measured experimentally for the isotherm temperatures ranging from 30 °C to 130 °C and pressure up to 3 MPa. A magnetic suspension balance based adsorption measurement unit is used to measure adsorption uptake gravimetrically. The presented SAC-2/HFC-32 pair has adsorption uptake as high as 2.23 kg
_ref
/kg
_ads
(excess adsorption) and 2.34 kg
_ref
/kg
_ads
(absolute adsorption) at 30 °C and 1.67 MPa. To the best of our knowledge, it is the highest HFC-32 adsorption capacity onto any adsorbent available in the literature. The experimental data of adsorption/desorption isotherms show that there is no hysteresis for the studied pair. The data have been fitted with Tóth; Dubinin–Astakhov (D–A); and Guggenheim, Anderson, De-Boer (GAB) adsorption isotherm models. The parameters of adsorption isotherm models are optimized by nonlinear optimization technique. The D–A model fits the experimental data precisely as compared to other models. In addition, numerical values of isosteric heat of adsorption have also been extracted by means of Clausius–Clapeyron equation using adsorption isotherm models.

DOI： 10.1016/j.ijheatmasstransfer.2018.07.097

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A detailed investigation into the viscosity, density, and refractive index of a binary mixture of propane-1,3-diol/water was performed for the whole range of mass fractions of propane-1,3-diol. The viscosity and density were measured over a wide range of temperatures from T = 253.15 K to T = 353.15 K where possible, or to the nearest safe point before freezing. The refractive indices were measured for the same dilutions as in the case of the viscosity and density over a reduced temperature range of T = (278.15 to 318.15) K. A mathematical analysis via excess properties was conducted and fitted to the Redlich-Kister equation. Furthermore, a prediction of density data is provided by a polynomial and DIPPR exponential model. The viscosity data are fitted to Grunberg-Nissan, Lederer, McAllister, and Heric models and a new combined model with variable temperature and molar and mass fractions based on these models is presented. Data comparison of the propane-1,3-diol/water binary mixture is performed on propan-1,2-diol/water mixture as the physically closest binary system and application alternative fluid.

DOI： 10.1021/acs.jced.8b00403

記述言語：英語  

Effect of slant angle (α) of louvered strip insert on single-phase forced convection heat transfer and friction factor of internal flow was investigated experimentally. The parameter of slant angles (α) 15° 20° and 25° was examined at the Reynolds number (Re) of 5300–17,500. The plain tube was also performed for comparison. The results show that the louvered strip insert provided the increases in heat transfer and friction factor up to 77.02&#37; and 3.35 times above the plain tube. The results also indicate that heat transfer and friction factor increased with increasing slant angle. The highest slant angle yielded the highest thermal performance factor in the value of 1.12. Empirical correlations were also developed for Nusselt number and friction factor based on experimental data.

DOI： 10.1016/j.ijthermalsci.2018.08.025

記述言語：英語   掲載種別：研究論文（学術雑誌）  

One of the challenges in the development of heat exchangers is to minimize their energy consumption. This can be achieved by enhancing the heat transfer rate, which will boost the thermal performance of heat exchangers. Delta-wing vortex generators fitted in a double-pipe heat exchanger will generate vortices with more intermixing of the flowing fluid, and provide the improvement of convective heat transfer of the internal flow. In this study, double-sided delta-wing (T-W) tape inserts were designed to enhance convective heat transfer of a double-pipe heat exchanger. The effects of the wing-width ratio (0.31, 0.47, and 0.63) on the heat transfer and fluid flow characteristics of the heat exchanger were investigated by experiments where water was used as the working fluid and the Reynolds number was varied from 5300 to 14,500. The results were compared with those obtained for a plain tube and tube with longitudinal strip (L-S) insert. The T-W tape insert (wing-width ratio: 0.63) results in the highest average Nusselt number, where the average Nusselt number is higher by 177&#37; relative to that for the plain tube. Despite the significant heat transfer enhancement, the friction factor is 11.6 times higher relative to that for the plain tube, indicating that friction loss is more pronounced due to the presence of T-Ws. The T-W tape insert (wing-width ratio: 0.63) also results in the highest thermal performance factor (1.15). The Nusselt number, thermal performance factor, and friction factor of the heat exchanger increases as the wing-width ratio of the T-Ws increases. Based on the experimental data, empirical correlations were developed to predict the Nusselt number and friction factor of the double-pipe heat exchanger with T-W tape inserts.

DOI： 10.1016/j.applthermaleng.2018.09.009

記述言語：英語  

Adjusting the heat and moisture of a conditioned space is important to maintain the comfort of the air. Adding or removing heat and moisture depends mainly on the heat and mass transfer characteristics within the system. In this study, the heat and mass transfer characteristics, in the form of the Nusselt number (Nu) and the Sherwood number (Sh), of a honeycomb desiccant dehumidifier (HDDH) were investigated experimentally. The HDDH was driven by using the honeycomb desiccant configuration, which was constructed from a polymer adsorbent material. The adsorption temperature (T_ads) was considered as an adjustable parameter using values of 20 °C, 25 °C, and 35 °C. Each adsorption temperature was evaluated under the time intervals for the desorption and adsorption processes (switching time: τ) of 60:60 min, 60:90 min, 60:120 min, and 90:120 min. For the given parameters, the desorption temperature and mass flow rate of the air were kept unchanged at 55 °C and 0.1 kg/s, respectively. The results showed that the Nu and Sh are more evenly responsive to change of adsorption temperature than switching time. Low desorption temperature results in high values of Nu and Sh. However, variation of switching time produces little change in Nu and Sh. Empirical correlations were also developed in this study. The empirical correlations matched the experimental data well.

DOI： 10.1016/j.applthermaleng.2018.08.066

記述言語：その他  

After publishing our articles on the studies of the vapor–liquid phase distribution in a header type evaporator consisting of upward [refer to Wijayanta et al., 2016] and downward [refer to Wijayanta et al., 2017] minichannel-branching conduits, we were motivated to extend the work to the heating load acting on the branches because till date, it is believed to cause maldistribution. Refrigerant R134a experiments with heating loads from 50 to 300 W on the branches were performed. The vapor quality in the test section inlet was maintained between approximately 0.1 and 0.4. Although a larger phase separation occurred in the header at the maximum heating load of 300 W at a vapor quality in the test section inlet of 0.41, it was notable that the geometry configuration had a stronger effect on the phase distribution.

DOI： 10.1016/j.ijrefrig.2018.08.003

記述言語：英語  

Emission and heat rejection from automobiles are largely responsible for urban environmental issues. Adsorption systems driven by engine waste heat exhibit huge potential to meet the demand for cabin thermal comfort while improving fuel economy. However, the mechanical vapour compression (MVC) systems are still the undisputed champions in automobile air conditioning. This paper provides a critical review on the development and progress of adsorption heat pumps specifically for automobile air conditioning. In doing so, some of the progress and development in land-based adsorption chillers (heat pump), which are not realistically relevant to automobile adsorption systems, are explicitly excluded. Matching the energy density, durability, and reliability of the MVC systems remain major hurdles. The importance of improving the energy density based on the overall system weight or volume, real-world tests under various driving modes and durability aspects are discussed.

DOI： 10.3390/app8112061

記述言語：英語  

This chapter starts from introduction of water as a refrigerant, and suitability of water refrigerant for evaporative heat exchangers rather than for two phase flow heat exchangers is discussed from a thermodynamic point of view. Then, a theory and analytical studies of evaporative cooling processes are described using psychrometric chart. A new thermodynamic concept of evaporative cooling, which is a breakthrough in cooling technology, is introduced and explained. Lastly, applications of evaporative heat exchangers for air cooling/humidification and for water cooling are presented.

DOI： 10.1007/978-3-319-26695-4_22

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The present study investigates five kinds of adsorbents for desiccant air-conditioning (DAC) applications. Each adsorbent yield distinctive water vapor adsorption isotherm that can be categorized as type-I, type-II, type-III, type-V, and type-linear on the basis of the International Union of Pure and Applied Chemistry (IUPAC) classification. Ideal DAC cycle is evaluated for the air-conditioning (AC) applications, and steady-state moisture cycled (MCSS) is estimated by means of adsorption isobars. Results showed that the adsorbent enabling type-linear adsorption isotherm gives maximum MCSS for industrial AC processes of matches manufacturing/drying/storage, rubber dipped goods storage and photo studio drying room. However, adsorbent enabling type-V adsorption isotherm is found the optimum adsorbent for tobacco stemming/stripping/softening and optical lenses grinding. For industrial AC process of dipped surgical articles
adsorbents enabling type-II, type-linear, and type-I adsorption isotherms are found the optimum choice at low (&lt
68 °C), medium (68°C-87 °C), and high (&gt
87 °C) regeneration temperatures, respectively.

DOI： 10.1016/j.renene.2018.01.045

記述言語：英語  

Adsorber heat exchanger design has great importance in increasing the performance of the adsorption-based cooling system. In this study, a transient two-dimensional axisymmetric Computational Fluid Dynamics (CFD) model has been developed for the performance investigation of finned tube type adsorber using activated carbon and ethanol as the working pair. The operating conditions of the cooling system were 15, 20 and 80 for evaporation, cooling and heating temperatures, respectively. The simulated temperature profiles for different adsorbent thicknesses were validated with those from experimental data measured in our laboratory. Moreover, the error in mass and energy balance were 3&#37; and 7.88&#37;, respectively. Besides, the performance investigation has been performed for cycle time ranging from 600 s to 1400 s. The optimum cycle time was 800 s and the corresponding evaluated specific cooling power (SCP) and coefficient of performance (COP) were found to be 488 W/kg and 0.61, respectively. The developed CFD model will be used for fin height and fin pitch optimization and can be extended to other adsorbent-adsorbate based adsorption cooling system.

DOI： 10.3390/en11061499

記述言語：英語  

Renewable energy (RE) is the potential solution to the current world’s problems pertaining to the energy crisis and environmental concerns. Like other countries Bangladesh, which is currently starving for energy, has given more importance to RE especially solar energy to mitigate the energy-related problems. According to RE policy of Bangladesh, the targeted RE share was 5&#37; to be achieved by 2015 (500 MW). At the beginning of 2018, the country was able to install ~506 MW from RE sources (3.10&#37;), in which significant portion comes from solar energy. The factors that contributed mainly to achieve the target are government policies and initiatives, international influence, solar panel price reduction, private sector participation, public awareness. In this study, the influences of these factors have been discussed. Besides, the technologies implemented for the fulfillment of RE share target has been analyzed.

DOI： 10.5109/1936220

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Titania-based nanofluid flowing inside a circular tube under the boundary condition of a horizontal uniformly heated wall was investigated numerically for both laminar and turbulent flows. In this work, an innovative numerical method using an Eulerian approach for the two-phase mixture model was used to simulate the flow and convective heat transfer characteristics. The effect of nanoparticle loading and Reynolds number on the flow and heat transfer characteristics was observed. The Reynolds number was 500 and 1200 for laminar flow, while for turbulent flow, the Reynolds number was varied in the range from 4000 to 14,000. A comparison with the established empirical correlations was made. The results clearly showed at the laminar and turbulent flows that the existing nanoparticles provided a considerable enhancement in the convective heat transfer. For laminar flow, the numerical results found that the enhancement in the convective heat transfer coefficient of nanofluids were 4.63, 11.47, and 20.20&#37; for nanoparticle loadings of 0.24, 0.60, and 1.18 vol.&#37;, respectively. On the other hand, for turbulent flow, the corresponding heat transfer increases were 4.04, 10.33, and 21.87&#37;.

DOI： 10.3390/en11061584

記述言語：英語  

The current research highlights the potential of using desiccant dehumidification technology with the merits of low initial energy consumptions. The system consists of desiccant (DSC) block units, dehumidification and regeneration air sources, air flow control valves, and a set of the heat exchanger. Attention was given to the DSC blocks. The blocks were made of hydrophilic polymer with honeycomb shaped. The present study focuses on the heat and mass transfer (HMT) characteristics to enhance the performance of the system. Three different process air temperatures of 20°C, 25°C, and 35°C were investigated under constant regeneration air temperature of 55°C and inlet air velocity of 0.1 kg/s. For each process air temperature, four different switching time ratios were also introduced to examine the HMT balance of the DSC blocks. The results revealed that the dehumidification capacity of the DSC system has high potential as air conditioning devices. The discrepancy of HMT found was less than 8&#37;. Hence, the experimental methods were reliable to conduct the further experiments.

DOI： 10.5109/1936212

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The performance of a solar hot water system is assessed for heat pump and domestic heating applications. Thermodynamic analysis on a serpentine-type thermosyphon flat-plate solar heater is conducted using the Second Law of thermodynamics. Exergetic optimization is first performed to determine the parameters for the maximum exergy efficiency using MATLAB optimization toolbox. Geometric parameters (collector surface area, dimensions, and pipe diameter), optical parameters (transmittance absorptance product), ambient temperature, solar irradiation and operating parameters (mass flow rate, fluid temperature, and overall heat transfer (loss) coefficient) are accounted for in the optimization scheme. The exergy efficiency at optimum condition is found to be 3.72&#37;. The results are validated using experimental data and found to be in good agreement. The analysis is further extended to the influence of various operating parameters on the exergetic efficiency. It is observed that optical and thermal exergy losses contribute almost 20&#37;, whereas approximately 77&#37; exergy destruction is contributed by the thermal energy conversion. Exergy destruction due to pressure drop is found negligible. The result of this analysis can be used for designing and optimization of domestic heat pump system and hot water application.

DOI： 10.3390/app8030391

記述言語：英語  

Present study provides the applicability of desiccant drying system (DDS) for the drying of cereals grain at low temperature and lower humidity. The performance of two drying approaches with two desiccant materials i.e. silica gel and lithium chloride (LiCl) have been analyzed by a desiccant dehumidification model available in literature. Two desiccant drying cases discussed are: Case-I, latent load control effect, Case-II both latent and sensible load control effect. Case-I approach seems more effective towards the drying of delicate and temperature sensitive agricultural product like seeds. However, results showed that Case-II gives more economical and energy saving drying solution for the commercial purpose drying. Regarding the appropriate desiccant material used, LiCl is appropriate choice for Case-I and silica gel is appropriate choice for Case-II.

記述言語：英語  

Solar-chimney assisted evaporative cooling based passive-air-conditioning (SCAC) system has been investigated for different climatic cities of Pakistan. Driving force of system is based on solar chimney and electric fan for day and night time operations, respectively. Ideal temperature and humidity zones are formulated for agricultural products’ storage and animals’ thermal comfort. Recent studies have proven the advancement of Maisotsenko Cycle (M-Cycle) in air-conditioning (AC) field; therefore, SCAC system utilizes M-Cycle conception in order to achieve dew-point cooling. On the basis of M-Cycle experimental data available via literature, study provides thermodynamic investigation of SCAC system for various conditions. Two simplified correlations are developed for performance evaluation of M-Cycle unit. Both correlations showed precise agreement with experimental data with R² > 0.95. The SCAC system could achieve sensible load of AC efficiently for various applications; however, performance index varies according to climatic conditions. The SCAC system’s applicability was found limited in humid areas because of nature of M-Cycle operation. Therefore, it has been concluded that system may not be sustainable as standalone AC, but it can be a convenient solution in order to reduce the AC load. Moreover, it can provide chilled ceiling for various applications with the low-cost operation. It can be efficiently utilized in most of the dry and moderate areas, whereas, the system’s applicability is limited in humid and water scared regions.

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

Machining is one of the largest and most widely used methods of production segments in industries. In this way, cutting fluids play an important role in minimizing production time, cost, and energy in various machining operations. This paper presents an experimental investigation into minimum quantity lubrication (MQL) with Al₂O₃ nanoparticles in drilling process of common rail as work material with DPSCM 435H code to analyze its influence on cutting parameters. Al₂O₃ has been selected for nanoparticles in this study due to its non-toxicity and spherical shapes for enhanced tribological attributes. Experiments were carried out for two different conditions; MQL + nanofluids (250 ml/h) and conventional cutting fluid (15 liters/min). In this work, nanofluid was prepared by adding Al₂O₃ nanoparticles (13 nm size) into the conventional cutting fluid in the specific proportion of 1.2 vol.%. The experiment results reveal that the performance of Al₂O₃ nanofluid in term surface roughness is better compared to the conventional cutting fluid, but the result of cutting temperature and chip morphology does not match with the previous experiment because volume fraction of nanofluid is too high. It means the specific proportion of 1.2 vol.% nanofluid is not best volume fraction for getting best cooling properties. This experiment does not focus on variations of volume fraction but on cooling conditions.

DOI： 10.1063/1.5024115

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

Turbulator is recognized as a method to increase the performance of the heat exchanger. Turbulator in the form of V-cut twisted tape insert could help to increase the performance by enhancing the coefficient of the heat transfer. This paper proposes a new design of V-cut twisted tape insert (VTT) with different width ratio (w/W), which investigated on the heat transfer enhancement, in the form of Nusselt number (Nu) and friction factor (f) characteristics. Three different width ratios (w/W) 0.32
0.38 and 0.48 are introduced in this experiment. The working fluid is the hot water in the inner tube and cold water in the annulus, the flow direction is counter-flow. The temperature inlet of hot water is kept constant at 60°C while the flow rate is in the range of Reynolds number 5400 - 17,350. The heat exchanger without insertion (plain tube) and typical twisted tape insert (TT) are examined for comparison. Results indicate that the proposed VTT increases the heat transfer, friction factor, and thermal performance of the heat exchanger. Under the similar condition, VTT provides the best performance in comparison with TT and plain tube. Decreasing width ratio (w/W) increases the heat transfer and thermal performance. However, when the heat transfer is increased, the friction factor is also increasing. The results also revealed that the use of the VTT and TT, the increase in the heat transfer and friction factor up to 97&#37; and 3.48 times of the plain tube. The highest thermal performance is 1.4.

DOI： 10.1063/1.5024097

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

Machining is one of the largest and most widely used methods of production segments in industries. In this way, cutting fluids play an important role in minimizing production time, cost, and energy in various machining operations. This paper presents an experimental investigation into minimum quantity lubrication (MQL) with Al2O3 nanoparticles in drilling process of common rail as work material with DPSCM 435H code to analyze its influence on cutting parameters. Al2O3 has been selected for nanoparticles in this study due to its non-toxicity and spherical shapes for enhanced tribological attributes. Experiments were carried out for two different conditions
MQL + nanofluids (250 ml/h) and conventional cutting fluid (15 liters/min). In this work, nanofluid was prepared by adding Al2O3 nanoparticles (13 nm size) into the conventional cutting fluid in the specific proportion of 1.2 vol.&#37;. The experiment results reveal that the performance of Al2O3 nanofluid in term surface roughness is better compared to the conventional cutting fluid, but the result of cutting temperature and chip morphology does not match with the previous experiment because volume fraction of nanofluid is too high. It means the specific proportion of 1.2 vol.&#37; nanofluid is not best volume fraction for getting best cooling properties. This experiment does not focus on variations of volume fraction but on cooling conditions.

DOI： 10.1063/1.5024115

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

Turbulator is recognized as a method to increase the performance of the heat exchanger. Turbulator in the form of V-cut twisted tape insert could help to increase the performance by enhancing the coefficient of the heat transfer. This paper proposes a new design of V-cut twisted tape insert (VTT) with different width ratio (w/W), which investigated on the heat transfer enhancement, in the form of Nusselt number (Nu) and friction factor (f) characteristics. Three different width ratios (w/W) 0.32; 0.38 and 0.48 are introduced in this experiment. The working fluid is the hot water in the inner tube and cold water in the annulus, the flow direction is counter-flow. The temperature inlet of hot water is kept constant at 60°C while the flow rate is in the range of Reynolds number 5400 - 17,350. The heat exchanger without insertion (plain tube) and typical twisted tape insert (TT) are examined for comparison. Results indicate that the proposed VTT increases the heat transfer, friction factor, and thermal performance of the heat exchanger. Under the similar condition, VTT provides the best performance in comparison with TT and plain tube. Decreasing width ratio (w/W) increases the heat transfer and thermal performance. However, when the heat transfer is increased, the friction factor is also increasing. The results also revealed that the use of the VTT and TT, the increase in the heat transfer and friction factor up to 97% and 3.48 times of the plain tube. The highest thermal performance is 1.4.

DOI： 10.1063/1.5024097

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The present study provides performance evaluation of two kinds of crosslinked hydrophilic organic polymer sorbents (PS-I and PS-II) for desiccant air-conditioning applications. In this regard, optimum temperature and humidity zones are established for various air-conditioning applications which include (i) humans’ thermal comfort, (ii) animals’ thermal comfort, and (iii) postharvest storage of fruits/vegetables. Honeycomb-like desiccant blocks composed of PS-I/PS-II are assumed for numerical simulation analysis. The numerical simulation model is programmed into MATLAB which utilizes the scientific relationships of adsorption isotherms, adsorption kinetics, isosteric heat of adsorption, and thermophysical properties for each sorbent. A particular desiccant air-conditioning system design is proposed, and numerical simulation has been conducted for the performance evaluation of PS-I and PS-II. According to the results, PS-I enables higher dehumidification than PS-II at low regeneration temperature (50℃) and cycle time of 60:90 min. It is because the PS-I possesses better water vapor sorption kinetics as compared to PS-II. Although the PS-II enabled higher steady-state adsorption amount but it could not influence the overall system performance. On the other hand, the optimum performance by the PS-II is limited to relatively long cycle time and higher regeneration temperature (≥80℃). It has been concluded that the PS-I is relatively better choice for desiccant air-conditioning, and consequently can be considered for various air-conditioning applications. Furthermore, effects of mass flow rate, isosteric heat of adsorption, regeneration temperature, and cycle time on air humidity ratio and air temperature profiles have been discussed in order to highlight the performance variability of desiccant air-conditioning system.

DOI： 10.1177/0263617417692338

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (di) called blockage ratio (Rb) of 0.28, 0.35 and 0.42 were tested and their performance was compared to that of a longitudinal strip and plain tube under similar test flow conditions. Experiments were conducted over a wide range of flow rates, 3.35 × 10-5-8.33 × 10-5 m3/s, which correspond to 5500 ≥ Reynolds number (Re) ≥ 14,500 in the 14.3 mm i.d. tube. The results revealed that using DWTs dramatically increased the Nusselt number (Nu) by as much as 364.3&#37; and the friction factor (f) by 15.5 times compared with those of a plain tube. Thermal performance (η) increased with a corresponding increase in Rb. The highest thermal performance (η) obtained was 1.4. Showing a notable improvement on the thermal performance of the system, DWTs are proposed as a favorable insert device.

DOI： 10.3390/app8020181

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Equilibrium adsorption uptake and kinetics of ethanol onto highly porous activated carbons (ACs) derived from two types of biomass namely waste palm trunk (WPT) and mangrove (M) have been experimentally measured at adsorption temperatures ranging from 30 to 70 degrees C for various evaporation pressures. A magnetic suspension adsorption measurement unit has been used for the experimental measurements. Four well-known adsorption isotherm models have been employed to fit the experimental data whilst two classical adsorption kinetics models i.e. Linear driving force (LDF) model and Fickian diffusion (FD) model are used to predict the experimental kinetics data. Among the four isotherm models Dubinin Astakhov (D-A), and Toth equations agree well with the experimental uptake data for both ACs. The diffusion time constants are calculated at each adsorption temperature for WPT-AC/ethanol and M-AC/ethanol pairs. Moreover, activation energy and pre-exponential constant have been determined from the Arrhenius equation. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.applthermaleng.2017.04.099

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Knowledge of adsorption characteristics of adsorbent-adsorbate pairs is essential for designing adsorption beds for adsorption cooling and adsorptive gas capturing applications. We investigated the adsorption isotherms and the adsorption kinetics of CO2 onto microporous activated carbon powder of type Maxsorb III. Measurements were performed with gravimetric apparatus for temperatures from 30 to 70 degrees C and pressures up to 7 MPa for adsorption isotherms and up to 4 MPa for adsorption kinetics. The gravimetric adsorption data obtained were consistent with previously measured isotherms with volumetric apparatus. Both absolute and excess adsorption data have been fitted precisely with Toth and Dubinin-Astakhov isotherm equations. The classical linear driving force (LDF) model with a constant mass transfer coefficient failed to correlate the experimental adsorption kinetics data. To overcome this problem, the authors presented a modified LDF equation with a variable mass transfer coefficient which is a function of the equilibrium and instantaneous uptakes. This modified LDF equation led to a better fitting and could be implemented easily in simulation of pressure swing adsorption (PSA), temperature swing adsorption (TSA) and adsorption chiller applications. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijheatmasstransfer.2016.12.114

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A combined adsorption and mechanical vapor compression system is a reasonable option to reduce the consumption of fossil fuels for air conditioning by utilizing waste heat. Performance predictions of combined adsorption and mechanical vapor compression systems require detailed dynamic modeling because the transitional characteristics explain the nature of the adsorption system. It is, however, desirable to simplify the model for practical use at engineering stages. Since the mechanical vapor compression system is based on the steady-state thermodynamic cycle, a semi-steady-state modeling of adsorption cycles would be functional for analysis of combined systems. In our study, the analytical solution of transient simulation for adsorption cycles was combined with a steady-state mathematical model of the mechanical vapor compression system. The performance of the combined system was analyzed based on the model developed, taking into account the cycle time of the adsorption cycle. The results show the performance characteristics as well as the energy-saving potential of the combined system.

DOI： 10.1080/01457632.2016.1195135

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Experimental validation of simulated adsorber/desorber beds for sorption cooling applications is essential to obtain reliable results. We have conducted rigorous simulation of the adsorption process occurring in a finned tube adsorber utilizing 2D-axisymmetric geometry. The adsorber uses activated carbon ethanol as adsorbent refrigerant pair. It is cooled with water at nearly 30 and experiencing a sharp pressure increase of ethanol from 0.95 kPa initially to 6 kPa. The simulated temperatures at adsorbent thicknesses of 0, 1, 5 and 10 mm from tube outer diameter showed an increase in adsorbent temperature up to 20 degrees C from its initial temperature. They were slightly higher at start of adsorption and were consistent with experimental data at higher flow time. The validated CFD model will serve as a base for evaluating and optimizing activated carbon ethanol adsorption cooling cycle. It can be extended also to different adsorber designs and other adsorbent adsorbate pairs. (C) 2016 Elsevier Ltd and IIR. All rights reserved.

DOI： 10.1016/j.ijrefrig.2016.10.019

記述言語：その他  

Experimental validation of simulated adsorber/desorber beds for sorption cooling applications is essential to obtain reliable results. We have conducted rigorous simulation of the adsorption process occurring in a finned tube adsorber utilizing 2D-axisymmetric geometry. The adsorber uses activated carbon–ethanol as adsorbent–refrigerant pair. It is cooled with water at nearly 30 °C and experiencing a sharp pressure increase of ethanol from 0.95 kPa initially to 6 kPa. The simulated temperatures at adsorbent thicknesses of 0, 1, 5 and 10 mm from tube outer diameter showed an increase in adsorbent temperature up to 20 °C from its initial temperature. They were slightly higher at start of adsorption and were consistent with experimental data at higher flow time. The validated CFD model will serve as a base for evaluating and optimizing activated carbon–ethanol adsorption cooling cycle. It can be extended also to different adsorber designs and other adsorbent–adsorbate pairs.

DOI： 10.1016/j.ijrefrig.2016.10.019

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The system energy efficiency will decline with the decrease of evaporator capacity because the use of more branches in evaporators increases maldistribution. This paper presents experimental study of several design options for downward flow to reduce the maldistribution. Two-phase flow distribution in a header type evaporator applied for CO2 have been experimentally investigated because the refrigeration system based on carbon dioxide (CO2) as a refrigerant is near ideal. Since the CO2 system works around critical pressure, an alternative method to predict the flow distribution of CO2 header type evaporator is inevitable. R134a is used as the alternative working fluid in the present study. Similarity hypothesis between CO2 and R134a is applied (refer to Wijayanta et al., 2016). R134a headers are tested and the experimental work is applicable to CO2. The R134a experiments were conducted at saturation temperature of about 21 degrees C, refrigerant mass flow range between 10 and 30 kg/h which corresponds to about 44 and 130 kg/m(2) sin the 9 mm i.d. header, and average vapor quality in the test section inlet of about 0.1-0.4. The test section consists of a horizontal header with 3 and 6 vertically downward replaceable branching conduits. The vapor-liquid phase mass flows enter into the branches are measured to propose the configuration of the header that has the minimum maldistribution. Empirical correlation of the vapor liquid distribution is developed. Estimated CO2 distribution for the proper header is determined based on R134a experimental data using the similarity hypothesis. The developed flow pattern map for R134a and CO2 is also proposed. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.expthermflusci.2016.09.011

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（その他学術会議資料等）  

The Adsorption heat pump is a technology for cooling and heating by using hot water as a driving heat source. It will largely contribute to energy savings when it is driven by solar thermal energy or waste heat. The system is available in the market worldwide, and there are many examples of application to heat recovery in factories and to solar cooling systems. In the present system, silica gel and zeolite are popular adsorbents in combination with water refrigerant. Our study focused on activated carbon-ethanol pair for adsorption cooling system because of the potential to compete with conventional systems in terms of coefficient of performance. In addition, activated-ethanol pair can generally produce larger cooling effect by an adsorption-desorption cycle compared with that of the conventional pairs in terms of cooling effect per unit adsorbent mass. After the potential of a commercially available activated carbon with highest level specific surface area was evaluated, we developed a new activated carbon that has the optimum pore characteristics for the purpose of solar or waste heat driven cooling systems. In this paper, comparison of refrigerants for adsorption heat pump application is presented, and a newly developed activated carbon for ethanol adsorption heat pump is introduced.

DOI： 10.1063/1.4968250

記述言語：英語  

The Maisotsenko Cycle (M-Cycle) is a thermodynamic conception which captures energy from the air by utilizing the psychrometric renewable energy available from the latent heat of water evaporating into the air. The cycle is well-known in the air-conditioning (AC) field due to its potential of dew-point evaporative cooling. However, its applicability has been recently expanded in several energy recovery applications. Therefore, the present study provides the overview of M-Cycle and its application in various heating, ventilation, and air-conditioning (HVAC) systems; cooling systems; and gas turbine power cycles. Principle and features of the M-Cycle are discussed in comparison with conventional evaporative cooling, and consequently the thermodynamic limitation of the cycle is highlighted. It is reported that the standalone M-Cycle AC (MAC) system can achieve the AC load efficiently when the ambient air humidity is not so high regardless of ambient air temperature. Various modifications in MAC system design have been reviewed in order to investigate the M-Cycle applicability in humid regions. It is found that the hybrid, ejector, and desiccant based MAC systems enable a huge energy saving potential to achieve the sensible and latent load of AC in humid regions. Similarly, the overall system performance is significantly improved when the M-Cycle is utilized in cooling towers and evaporative condensers. Furthermore, the M-Cycle conception in gas turbine cycles has been realized recently in which the M-Cycle recuperator provides not only hot and humidified air for combustion but also recovers the heat from the turbine exhaust gases. The M-Cycle nature helps to provide the cooled air for turbine inlet air cooling and to control the pollution by reducing NOx formation during combustion. The study reviews three distinguished Maisotsenko gas turbine power cycles and their comparison with the conventional cycles, which shows the M-Cycle significance in power industry. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.rser.2016.08.022

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The adsorption rate is an important parameter for accurate performance estimation of adsorbent-refrigerant based adsorption cooling cycles. Here, we have investigated the response of two adsorption kinetics models of activated carbon-ethanol pair by means of CFD simulation. The isothermal assumption used in estimating the diffusion time constant of Fickian diffusion and linear driving force (LDF) models led to divergence and underestimated adsorption uptakes, respectively. By including the simulated adsorbent temperature profile in fitting of LDF model to experimental data, we assessed the non-isothermal diffusion time constants which were 2.5 to 5 times higher than those evaluated previously with isothermal assumption. The goodness of fitting, evaluated with coefficient of determination (R-2), improved and became higher than 0.95 from 0.73 initially. The developed non isothermal LDF equation allows accurate heat and mass transfer simulations and performance optimization of large scale adsorption/desorption bed employing activated carbon ethanol pair for adsorption cooling applications. (C) 2016 Elsevier Ltd and IIR. All rights reserved.

DOI： 10.1016/j.ijrefrig.2016.08.004

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Adsorption of carbon dioxide onto highly porous activated carbon based consolidated composite adsorbent has been experimentally investigated. Experiments have been conducted at temperatures of 30, 50, 70 degrees C and pressures up to 7 MPa using magnetic suspension adsorption measurement unit. The innovative adsorption isotherms data have been correlated using three isotherm models namely, Langmuir, Toth, and modified Dubinin-Astakhov (D-A). The studied models successfully fitted with the experimental data and Toth isotherm model shows a better fitting. Results showed that the volumetric adsorption capacity of CO2 onto the studied consolidated composite is higher than that of CO2 onto parent activated carbon powder (Maxsorb III). The isosteric heat of adsorption of the studied pairs has been calculated from isotherm data. The performance of ideal adsorption cooling cycle, employing consolidated composite adsorbent/CO2 pair, has also been simulated at three different evaporator temperatures, namely 5, 10 and 15 degrees C along with a coolant temperature of 25 degrees C and heat source temperatures ranging from 45 to 90 degrees C. The estimated thermodynamic parameters and isotherm data are important for further development of CO2 based adsorption cooling systems. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.applthermaleng.2016.08.031

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Since the refrigeration system based on carbon dioxide (CO2) as a refrigerant is near ideal, liquid-vapor phase distribution in a header type evaporator applied for CO2 has been experimentally investigated. The test section consists of a horizontal header and 3, 6 or 8 vertically upward replaceable branching conduits. The header is made of transparent polyvinyl chloride (PVC) resin for observing the flow regime, and each conduit is composed of an aluminum disk plate and an aluminum minichannel-branching conduit. In order to develop the lowest maldistribution header, several headers with various insertion depths are examined. Since the CO2 system operates at around the supercritical conditions, it is a little bit difficult to observe the flow regime for CO2 at high pressure, therefore, R134a is used as the alternative working fluid in this study. Similarity hypothesis between CO2 and R134a is proposed. The modified Baker flow pattern map (refer to Scott, 1963) is applied to define the equivalent experimental conditions for both R134a and CO2. R134a headers are tested and the experimental work is applicable to CO2. The R134a experiments were conducted at saturation temperature of about 21 degrees C, refrigerant mass flow range between 10 and 30 kg/h which corresponds to about 44 and 130 kg/m(2) s in the 9 mm i.d. header, and average vapor quality in the test section inlet of about 0.1, 0.2, 0.3 and 0.4. The R134a vapor-liquid phase mass flows entering into the branches were measured. The predicted flow regimes at each branch inlet in the header, predicted using flow pattern map in the form of vapor quality as the abscissa versus mass velocity as the ordinate refer to Wojtan et al. (2005), were utilized to understand the observation of phase separation. The liquid-vapor phase distribution of CO2 was estimated based on the R134a experimental result. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.expthermflusci.2016.03.021

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Water vapor sorption kinetics of two polymer based sorbents has been experimentally measured at adsorption temperatures of 20, 30, 50, 70 and 80 degrees C using a magnetic suspension adsorption measurement unit. The experimental data is employed to commonly known adsorption kinetics approximations i.e. Linear driving force (LDF) model, Fickian diffusion (FD) model, and Semi-infinite model. All these models could not approximate the adsorption kinetics of polymer based sorbents, however, the LDF model is modified which successfully predicts the experimental kinetics for short-time and long-time estimation. For both sorbents, the diffusion time constant has been calculated at each adsorption temperature, and consequently, activation energy and pre-exponential constant are found from Arrhenius plot. The variation of diffusion time constant with relative pressure and adsorption temperature is discussed in relation with typical behavior of polymer/water pairs. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.applthermaleng.2016.05.192

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This study investigated the cycle optimization of four-bed, silica gel-water adsorption with reheat cycle, where the desorber (upper bed) and adsorber (lower bed) always interact with the condenser and evaporator, to exploit a low heat-source temperature. In a previous study, the performance of a reheat cycle with chilled water outlet temperature fixed at 9 degrees C was observed without considering the cycle optimization. Maintaining a constant chilled water outlet temperature is also of equal importance to improve the conversion efficiency so that maximum cooling capacity can be derived. In this paper, a simulation model of reheat adsorption cycles is developed to analyze the optimization of the cycle time, including adsorption/desorption time, mass recovery time, and preheating/precooling time, with chilled water outlet temperature fixed. The reheat working principle is also introduced. The proposed cycle is compared with the four-bed versison without reheat cycle in terms of coefficient of performance (COP) and cooling capacity. The result shows that the performance of a reheat cycle is superior to that of four-bed version without reheat, especially for low heat-source temperature. For low heat-source temperature (55-65 degrees C) both COP and cooling capacity of the reheat cycle with optimization were raised significantly compared to the high heat-source temperature (70-80 degrees C).

DOI： 10.1080/01457632.2015.1066650

記述言語：英語  

DOI： 10.1080/01457632.2015.1066645

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this study, consolidated composite adsorbents which are combinations of a highly porous activated carbon powder (Maxsorb III), expanded graphite (EG) and binder have been developed and characterized. Porous properties of the developed composite adsorbents have been investigated experimentally using Nitrogen adsorption. Adsorption equilibrium uptakes of ethanol onto composite adsorbents have been measured and correlated using suitable adsorption isotherm models. Thermal conductivity of the prepared adsorbents has also been measured using the NETZSCH LFA 457 MicroFlash system. Experimental results show that the adsorption equilibrium capacity of ethanol onto consolidated composite (70&#37; Maxsorb III, 20&#37; EG, 10&#37; binder) is 0.89 kg kg(-1) which is about 74&#37; of the maximum adsorption uptake of parent Maxsorb III/ethanol pair. This is clear evidence that the binder doesn't sacrifice the adsorption capacity of Maxsorb III of consolidated composites. It is also found that the thermal conductivity of the developed consolidated adsorbents increased to 11 times that of Maxsorb III powder. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.applthermaleng.2015.12.105

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In the present study, water vapor adsorption onto silica-gel, activated carbon powder (ACP) and activated carbon fiber (ACF) has been experimentally measured at 20, 30 and 50 degrees C using a volumetric method based adsorption measurement apparatus for greenhouse air-conditioning (AC). The Guggenheim-Anderson-De Boer and Dubinin-Astakhov adsorption models are used to fit the adsorption data of silica-gel and ACP/ACF, respectively. The isosteric heat of adsorption is determined by Clausius-Clapeyron relationship. The adsorbents are evaluated for low-temperature regeneration with aim to develop solar operated AC system for greenhouses. Ideal growth zone for agricultural products is determined by which the steady-state desiccant AC cycle is evaluated on the psychometric chart and adsorption isobars.
Steady-state moisture cycled (MCSS) by each adsorbent is determined for demand category-I, II and III which are based on 60&#37;, 40&#37; and 20&#37; relative humidity of dehumidified air, respectively. In case of demand category-I, the ACP enables maximum MCSS at all regeneration temperatures (T-reg), ideally sitting at 47 degrees C. The ACF enables double MCSS as compared to silica-gel during demand category-II at T-reg >= 59 degrees C. However, the silica-gel is found the only applicable adsorbent for the demand category-III. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.renene.2015.09.015

記述言語：英語  

To address the importance of desiccant air-conditioning (DAC) systems, this paper discusses the comparison between DAC and conventional vapor compression air-conditioning (VAC). Performance and economic feasibility (PEF) of the system is conferred with reference literature to correlate the types of DAC system from the perspective of energy saving and system payback period. The present study provides three examples of existing desiccant cooling systems namely (i) standalone DAC system, (ii) single-stage hybrid DAC system, and (iii) two-stage hybrid DAC system, which highlight their importance under different environmental conditions. This study provides scientific and experimental supports on how the standalone or hybrid desiccant cooling can be a supplement to the exiting VAC system. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.rser.2015.02.038

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Two polymer based sorbents PS-I and PS-II are analyzed for water sorption applications. Adsorption/desorption isotherms of water vapor onto PS-I and PS-II have been experimentally measured using a magnetic suspension adsorption measurement unit for adsorber temperature ranges 20-80 A degrees C and evaporator temperature ranges 2-73 A degrees C. The equilibrium adsorption uptake of water vapors corresponding to saturation condition at 30 A degrees C by PS-I and PS-II was found nearly 2 and 2.5 times higher than the conventional silica-gel, respectively. Adsorption data has been analyzed for various adsorption models which include Brunauer-Emmett-Teller (BET); Freundlich; Dubinin-Astakhov (D-A); Oswin; and Guggenheim-Anderson-de Boer (GAB) model. The GAB and BET model give the good fit for relative pressure range of 0.10-0.90 and 0.05-0.35, respectively. At all adsorption temperatures of both sorbents, the monolayer uptake by the GAB model is found higher than the BET model. Effect of adsorption potential on adsorption uptake is highlighted in relation with water vapor adsorption mechanism. The isosteric heat of water vapor adsorption is determined for both sorbents using Clausius-Clapeyron equation.

DOI： 10.1007/s10450-015-9663-y

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1615/HeatTransRes.2014007215

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Adsorption characteristics of ethanol onto two promising adsorbents have been investigated for developing high performance adsorption chillers. These new adsorbents are based on spherical phenol resin treated with different mass ratios of KOH named as KOH4-PR and KOH6-PR. Experimental adsorption isotherm measurements show that the adsorption capacity of KOH4-PR/ethanol is as high as 1.43 kg kg(-1) whilst one kg of KOH6-PR able to adsorb nearly about 2 kg of ethanol. To the best of our knowledge, the studied adsorbents possess the highest ethanol uptake. Moreover, it is found that the KOH4-PR/ethanol pair has notably high adsorption kinetics at the lower range of adsorption temperatures. Experimental measurements of adsorption uptake and adsorption uptake rate of the studied pairs have been analyzed and isosteric heats of adsorption have also been extracted. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijheatmasstransfer.2014.10.012

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This paper presents experimental and theoretical investigations of adsorption characteristics of ethanol onto metal organic framework namely MIL-101Cr. Adsorption isotherms and kinetics of the studied pair have been measured gravimetrically using a magnetic suspension adsorption measurement unit and volumetrically employing a Quantachrome Autosorb iQ MP machine. The present experiments have been conducted within relative pressures between 0.1 and 0.9 and adsorption temperatures ranging from 30 to 70 degrees C, which are suitable for adsorption cooling applications. Adsorption isotherm data exhibit that 1 kg of MIL-101Cr can adsorb as high as 1.1 kg of ethanol at adsorption temperature of 30 degrees C, and the Toth equation has been used to fit the experimentally measured data. As of the experimentally measured adsorption uptake rate data, the Fickian diffusion model is found to be suitable. These data are essential for designing a new generation of adsorption chiller. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.energy.2014.11.022

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The present study aims to investigate adsorption characteristics of ethanol onto activated carbon powders namely; parent Maxsorb III and surface treated Maxsorb III with controlled oxygen content. Experiments have been conducted gravimetrically using a magnetic suspension adsorption measurement unit. The measurements have been conducted within evaporator temperatures range from -14 to 77 degrees C and adsorption temperatures between 20 and 80 degrees C The Dubinin-Astakhov (D-A) adsorption model is found to be suitable to correlate the adsorption isotherm data. The isosteric heat of adsorption of the assorted adsorbent/refrigerant pairs has been estimated using Clausius-Clapeyron and the D-A equations. Effect of the refrigerant purity on the adsorption characteristics of the adsorbent/refrigerant pair is also discussed. The data extracted from this study are useful for the design of adsorption cooling, refrigeration and heat pump systems. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.applthermaleng.2014.03.062

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this paper, adsorption isotherms and kinetics of ethanol onto highly porous activated carbon powders have been investigated. Adsorbents used in the present study are (i) parent Maxsorb III, (ii) KOH-H-2 treated Maxsorb III, and (iii) H-2 treated Maxsorb Ill. Adsorption isotherms and kinetics of the assorted pairs have been measured using magnetic suspension adsorption measurement unit (MSB-VG-S2). Experiments have been conducted across assorted adsorption temperatures that are useful for the operation of adsorption chillers. The Dubinin-Astakhov equation is used to fit adsorption isotherms of parent Maxsorb III/ethanol and KOH-H-2 treated Maxsorb III pairs whilst the Dubinin-Radushkevich isotherm model is found to be more suitable for fitting of adsorption uptake of H-2-treated Maxsorb III/ethanol pair. Adsorption kinetics of assorted pairs are presented by the Fickian diffusion model. Experimental results show that, among the assorted pairs, H-2 treated Maxsorb III/ethanol pair possesses the highest adsorption equilibrium uptake. However, the diffusion time constant of KOH-H-2 treated Maxsorb III is found to be higher than that of other two studied pairs. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijheatmasstransfer.2014.02.046

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Double Effect Adsorption Refrigeration Cycle Using Silica gel-FAM Z01/Water Pair

DOI： 10.11322/tjsrae.31.1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Design and performance of Four-Stage Adsorption System

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This article presents the optimal cycle time and performance of two different types of silica gel-water-based three-bed adsorption chillers employing mass recovery with heating/cooling scheme. A new simulation program has been developed to analyze the effect of cycle time precisely on the performance of the systems. The particle swarm optimization (PSO) method has been used to optimize the cycle time and then the optimum performances of two chillers are compared. Sensitive analysis of cycle time has been conducted using the contour plot of specific cooling power (SCP) with driving heat source temperature at 80 degrees C. It is found that the center point of the contour indicates the maximum SCP value and optimal cycle time, which are comparable with the quantitative values obtained for the PSO method. Both three-bed mass recovery adsorption cycles can produce effective cooling at heat source temperature as low as 50 degrees C along with a coolant at 30 degrees C. The optimal SCP is similar for both cycles and is greater than that of the conventional two-bed adsorption system employing the same adsorbent-refrigerant pair. Consequently, the proposed comparison method is effective and useful to identify the best performance of adsorption cycles.

DOI： 10.1080/01457632.2012.753571

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The design of a four-bed three-stage adsorption cycle has been proposed to reduce the volume of the six-bed three-stage adsorption cycle. A simulation model for the proposed innovative cycle was developed to analyse the influence of cycle time on the system performance identifying the specific cooling power (SCP) and coefficient of performance (COP). A particle swarm optimization (PSO) technique was used to optimize the cycle time enabling us to maximize the SCP. PSO results showed that the optimal cycle time was decreased with heat source temperature and SCP value was proportional to heat source temperature. It was found that the proposed cycle could be driven by waste heat as low as 40 degrees C, along with coolant at 30 degrees C. Comparative study of optimized result indicated that the proposed cycle increased the performance significantly over a whole range of temperatures from 40 to 70 degrees C and reduced two adsorbent beds, compared to the six-bed three-stage cycle.

DOI： 10.3390/en6031365

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

If both EVs (Electric Vehicles, includes plug-in hybrid electric vehicles) and renewable energies spread in large quantities, it is possible to control the supply fluctuation of renewable energies using the storage battery of EVs. This research sought to show the charge load potential of EVs based on the state of the Japanese passenger car using traffic census results, etc. Furthermore, it tried to show the trend of the storage battery capacity according to time. From the estimated results: (1) the charge electricity of low and middle distance gets a majority of the total charge demand, (2) charge load changes according to time several times, and the minimum load is the number of gigawatt-hours at early morning, (3) if night charge is assumed, the standby charge demand of noon will reach tens of gigawatt-hours, it may have sufficient scale for supply fluctuation control of PVs. Although the present EV is not suitable for long-distance running, these are expected to be 30 or less percent of the total charge demand. The estimated storage capacity potential in this research will not change numbers of times. (c) 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(3): 3038, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22352

DOI： 10.1002/eej.22352

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This paper presents an innovative design of a three-bed two-stage silica gel-water based adsorption cycle aiming to minimize the overall size of four-bed two-stage cycle. One heat exchanger bed was removed from former four-bed two-stage system and operational strategy was taken to increase the adsorption time compare to desorption time in the proposed design. A simulation model for the proposed cycle was developed in order to analyze the influence of cycle time on the performance of the system in terms of specific cooling power (SCP) and coefficient of performance (COP). The cycle time was optimized to obtain the maximum SCP for different heat source temperatures using the particle swarm optimization (PSO) method. Sensitivity analysis of the cycle time was conducted using contour plot of SCP and chilled water outlet temperature for driving heat source temperature at 55°C. Optimize results were compared with the results of four-bed two-stage cycle. It was found that the SCP was increased for the proposed cycle over the whole range of regeneration temperature. The proposed cycle seems advantageous from the economic viewpoint due to its improved performance and reduced volume.

DOI： 10.1299/jee.7.92

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

全国アンケート調査による太陽光発電システムに関する導入意識とコンジョイント分析

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The solar chimney is a passive cooling technique to enhance the natural ventilation of buildings. The effect is, however, limited under hot and humid climatic conditions. In the study, the solar chimney was accompanied by a dew-point evaporative cooler. The dew-point evaporative cooler was integrated with the ceiling of a building. The air flow induced by the solar chimney was predicted by simulation, and the cooling effect of the dew-point evaporative cooler was also analyzed by heat and mass transfer simulation. The results showed that the system was capable of coping with internal heat gains of an ordinary office building. In addition, the optimal geometry of the evaporative cooling channel was revealed. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.enbuild.2011.05.004

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

Mサイクルを用いた建築一体型太陽エネルギー駆動冷房システムによる省エネルギー可能性の評価

DOI： 10.11322/tjsrae.28.269

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A numerical investigation of the double-effect adsorption refrigeration cycle is examined in this manuscript. The proposed cycle is based on the cascading adsorption cycle, where condensation heat that is produced in the top cycle is utilized as the driving heat source for the bottom cycle. The results show that the double-effect cycle produces a higher coefficient of performance (COP) as compared to that of the conventional single-stage cycle for driving temperatures between 100 degrees C and 150 degrees C in which the average cycle chilled water temperature is fixed at 9 degrees C. Moreover, the COP of the double-effect cycle is more than twice that of the single-stage cycle when the temperature reaches 130 degrees C. It is also observed that the adsorbent mass ratio of the high temperature cycle (HTC) to the low temperature cycle (LTC) affects the performance of the double-effect adsorption refrigeration cycle.

DOI： 10.3390/en3111704

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This study aims at exploiting optimal configurations of technologies combined with co-generation theoretically based on a linear optimization model. With the objective function defining primary energy consumption to be minimized, optimal solutions are derived analytically. They describe the technological configurations as well as associated conditions depending on their final energy demand. An interesting finding is that the essential parameters to determine the configurations are heat, cooling and steam demands normalized by power demand. The optimal solutions are also applied to investigate the competitiveness of co-generation related technologies. The optimal solutions yield critical conditions theoretically, which is useful to understand the priority of the technologies. A sensitivity analysis numerically indicates that absorption chillers can be superior to compression chillers even though the former has lower COP than the latter. Actual data of various types of co-generation are also examined to show the practical competitiveness. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.energy.2010.06.015

記述言語：日本語  

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.applthermaleng.2009.02.008

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/en20401170

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/en20300531

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/en20200202

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ijrefrig.2007.07.002

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.energy.2007.05.003

記述言語：英語  

記述言語：英語  

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語  

Fresh fruits and vegetables are perishable and possess short life under ambient conditions. Post-harvest losses are one of the major concerns in the storage of fruits and vegetables. In this regard, proper control of temperature and humidity is required to reduce post-harvest losses and enhance the shelf life of fruit and vegetables with the finest quality, quantity, and nutritive attributes. Several options such as vapor compression-based air-conditioning systems have been studied and implemented worldwide for possible storage of fruits and vegetables but consume a huge amount of energy and degrading the environment. Therefore, in this study, the energy-efficient standalone desiccant air conditioning (DAC) and Maisotsenko cycle-based desiccant air conditioning (M-DAC) systems were explored from the viewpoint of potential storage of fruits and vegetables. The systems analysis to check the feasibility was carried out in the climatic conditions of Multan, Pakistan. The proposed systems were thermodynamically explored from the viewpoint of ideal temperature and humidity control storage zones, cooling capacity, and coefficient of performance (COP). The results appreciably showed that the M-DAC system performed relatively better than the proposed standalone DAC system. It was found that the cooling capacity and COP of the M-DAC system were found 32.5 kJ/kg and 1.07, respectively, as compared with standalone DAC.

DOI： 10.1007/978-3-030-86394-4_4

Scopus

Poultry industries play a major role in Pakistan’s economy as well as developing countries. Poultry birds are sensitive to slight variation in ambient air temperature and humidity. Therefore, temperature-humidity control system is principally required for optimum growth of the birds. Conventionally, vapor-compression-based air-conditioning systems are used in poultry houses to control temperature and humidity. These systems degrade the environment and consume huge amount of primary energy. In this regard, the present study investigates energy-efficient thermally driven desiccant dehumidification-based evaporative cooling system for monthly basis climatic conditions of Multan (Pakistan). The present study explored standalone desiccant air-conditioning system (S-DAC) and Maisotsenko cycle assisted DAC system (M-DAC) using silica-gel and hydrophilic polymeric-sorbent desiccant materials from the viewpoints of slope of dehumidification line, dehumidification capacity, cooling capacity, and coefficient of performance (COP). In addition, the study explored surface temperature, surface area, total sensible heat loss, evaporative heat loss, total heat loss, and temperature-humidity index (THI) of the poultry birds. The results showed that the polymer-based M-DAC system was feasible in terms of maximum dehumidification capacity, cooling capacity, and COP (i.e., 4.3 g/kg-DA, 14.9 kJ/kg, and 0.5, respectively) and achieved thermal comfort (THI &lt; 30℃) of poultry birds throughout the year.

DOI： 10.1007/978-3-030-86394-4_2

Scopus

記述言語：英語   著書種別：学術書

記述言語：英語   著書種別：学術書

DOI： 10.1007/978-3-319-32003-8_22-1

記述言語：日本語   著書種別：学術書

記述言語：英語   著書種別：学術書

記述言語：英語   著書種別：学術書

開催年月日： 2015年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学（仙台）   国名：日本国  

開催年月日： 2015年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東北大学（仙台）   国名：日本国  

開催年月日： 2015年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡国際会議場（福岡）   国名：日本国  

開催年月日： 2015年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：福岡国際会議場（福岡）   国名：日本国  

開催年月日： 2015年4月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東京海洋大学（東京）   国名：日本国  

開催年月日： 2015年2月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：九州大学，福岡   国名：日本国  

開催年月日： 2014年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Buyeo, Korea   国名：大韓民国  

開催年月日： 2014年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：海峡メッセ下関，山口   国名：日本国  

開催年月日： 2014年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：佐賀大学，佐賀   国名：日本国  

開催年月日： 2014年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：アオッサ，福井   国名：日本国  

開催年月日： 2014年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：アオッサ，福井   国名：日本国  

開催年月日： 2012年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：熊本大学，熊本   国名：日本国  

開催年月日： 2012年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：熊本大学，熊本   国名：日本国  

開催年月日： 2012年9月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：北海道工業大学，北海道   国名：日本国  

開催年月日： 2012年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：北海道工業大学，北海道   国名：日本国  

開催年月日： 2012年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：九州大学医学部キャンパス   国名：日本国  

開催年月日： 2012年4月

記述言語：その他   会議種別：口頭発表（一般）  

開催地：東京海洋大学，東京   国名：日本国  

開催年月日： 2011年4月

記述言語：その他   会議種別：口頭発表（一般）  

開催地：東京海洋大学（東京）   国名：日本国  

開催年月日： 2011年4月

記述言語：その他   会議種別：口頭発表（一般）  

開催地：東京海洋大学（東京）   国名：日本国  

開催年月日： 2019年8月

記述言語：英語  

開催地：Montreal   国名：カナダ  

Electricity remains the main source of energy for conventional air-conditioning systems, while natural gas - is traditionally utilized for space heating. In both cases the thermodynamic processes are inefficient, as high-grade energy wastes its potential for the processes close to ambient temperatures. The paper describes the methods of multiplication of high, middle and low-grade heat to maximize the effect of space cooling and heating by combining thermally-driven ejector system with the heat recuperation process in the Maisotsenko cycle Heat and Mass Exchanger (HMX). Such a comprehensive and cost-efficient solution for space heating and cooling will help to lower the environmental loads at least twofold, save fossil fuels by 25-30&#37;, displace 100&#37; of the inhaled air at no extra cost and reduce by at least 10 times the energy consumption in the most intensive sector at the expense of the increased efficiency of the proposed technology over the existing systems.

開催年月日： 2019年8月

記述言語：英語  

開催地：Montreal   国名：カナダ  

Recently, the development of high temperature heat pump systems for heat recovery from industrial waste heat below 100 °C is one of important subjects to reduce primary energy consumption. However, in order to develop such systems, it is indispensable to use an environmentally acceptable refrigerant, highly efficient heat exchangers and highly efficient compressors. From this viewpoint, in the present study, the condensation of low GWP refrigerant R1234ze(Z) in vertical channels is investigated experimentally in order to establish optimum design method of plate-fin heat exchanger. Then, heat transfer coefficients are measured by two type cooling methods. One type is one side cooling method, another type is both cooling method. As the results, the heat transfer coefficient in consideration of fin efficiency of one side cooling method is higher than that of both cooling method in high quality.

開催年月日： 2018年10月

記述言語：英語  

開催地：Lahore   国名：パキスタン・イスラム共和国  

Air-conditioning should be considered as a basic need in developing countries like Pakistan. It is not only necessary for humans but also for agriculture sector especially for thermal comfort of livestock. Moreover, air-conditioning for the sake of livestock applications is almost negligible in developing countries like Pakistan. In this regard, many direct evaporative cooling systems are used conventionally in Pakistan, however, these systems are not feasible in monsoon season and in the humid areas of Pakistan. Therefore, desiccant based air-conditioning (D-AC) is a very promising solution for this problem. In this study, a comprehensive summary of the D-AC system supported by Maisotsenko-cycle based evaporative cooling and applicability of this system is discussed for livestock application in Pakistan. The requirements of humidity and temperature which are ideally required for thermal comfort of the livestock is represented on psychrometric chart. Different conditions of the air have been checked for temperature humidity index measurement i.e., ambient air and processed air through desiccant air conditioning system for climatic conditions for two major cities of Pakistan (Multan and Karachi). Moreover, some analyses have been concluded to examine the performance of D-AC system supported by M-cycle unit and crisscross its practicability for the studied region. Results express that M-cycle supported D-AC system can be a sustainable AC system for humid and hot climatic conditions of Pakistan. While the standalone D-AC system is good for humid but relatively lesser hot regions of Pakistan where temperature control is not so crucial.

開催年月日： 2018年10月

記述言語：英語  

開催地：Surakarta   国名：インドネシア共和国  

Nowadays nanofluids are widely used for heat transfer enhancement. Nanometer-sized particles added to base fluid enhance the thermal conductivity and thus increase the heat transfer rate. In the present study TiO ₂ nanoparticle with the average diameter, 21 nm is used. Titanium dioxide (TiO ₂ ) nanofluid prepared by dispersing nanoparticles in distilled water using the two- step method with volume concentration (0.05&#37; - 0.3&#37;), has been investigated. The force convective heat transfer coefficient and friction factor of the TiO ₂ /Distilled water nanofluid with different volume concentration and Reynolds number for flow in a counterflow double tube heat exchanger are studied in this research. The result shows that the convective heat transfer coefficient of nanofluid is higher than base fluid for the same mass flow rate and same inlet temperature of nanofluid. The Nusselt number increases with Reynolds number and volume concentration TiO ₂ /Distilled water of nanofluid. Meanwhile, micro-fin tube increases pressure drop in the flow path.

開催年月日： 2018年10月

記述言語：英語  

開催地：Surakarta   国名：インドネシア共和国  

Controlling the temperature and humidity is important to achieve a comfortable space for occupants. Numerous studies have shown that the desiccant air conditioning system offered great potential to solve this problem. However, to guaranty the continuous working of the system, desiccant air conditioning is required a regeneration process which always needs a high temperature. Most literature has shown that its required desorption temperature more than 60°C. From this motivation, with the humidity control consideration, in this present work, we performed an experimental investigation on desiccant dehumidification system for low desorption temperature. The aim of this study is to evaluate the capabilities of the desiccant system as a dehumidifier particularly focus on the dehumidifying rate and relative humidity limitation. The system was developed as a solid desiccant block which made of polymer material. The ratio between the adsorption and desorption area was equal to control the constant value of the mass flow rate of 0.1 kg/s. The alternating process between the desorption and adsorption phases was controlled by switching the time for each process 60 min and 120 min, for desorption and adsorption, respectively. The desorption temperatures were varied in the value of 35°C, 45°C, and 55°C. Adsorption temperature was introduced in the value of 20°C for all experimental conditions. The results show that a low desorption temperature still had great potential as a dehumidifier system. The dehumidifying rate increased with the increase of desorption temperature. The dehumidifying rates provided 0.34 g/s, 0.84 g/s and 1.12 g/s for desorption temperatures of 35°C, 45°C, and 55°C, respectively. The ability of the desiccant to reduce the humidity also increased with the increase of desorption temperature. For the lowest desorption temperature, even though its only at 35°C, it can reduce the relative humidity up to 20&#37;.

開催年月日： 2018年6月

記述言語：英語  

開催地：Sapporo, Hokkaido   国名：日本国  

Present study provides the applicability of desiccant drying system (DDS) for the drying of freshly harvested cereals grains in order to remove the moisture and safe level storage. Drying air conditions including the temperature and humidity affect the quality and appearance of the dried product. High temperature and higher humidity cause to loss of nutrient and color. Control of the latent load of drying air prior to use for drying seems more effective approach towards delicate and temperature sensitive grains like seeds of crop. DDS remove the moisture from the drying air and make it possible to dry at low temperature and low humidity. In present work the pertinence of DDS with two desiccant materials LiCl and Silica gel were analyzed. Drying of grains (wheat and rice) is studied for regeneration temperature 50-80ºC. Results showed that in case of desiccant material LiCl, process air temperature is higher and humidity is lowers as compared to the silica gel. Drying air potential per watt also showed that desiccant material LiCl found more economical to use as compared to silica gel for all range of regeneration temperature. However for different type of grains, there is optimum regeneration temperatures that give maximum drying potential per watt. For wheat and corn optimum regeneration temperature range found was 55-60ºC whereas for barly and rice was above 60ºC. Regarding the appropriate desiccant material used, LiCl was found appropriate choice for economical point of view however silica gel is appropriate choice for second approach.

開催年月日： 2018年6月

記述言語：英語  

開催地：Sapporo, Hokkaido   国名：日本国  

Recently, the development of high temperature heat pump systems for heat recovery from industrial waste heat below 100 °C is one of important subjects in order to reduce primary energy consumption. However, in order to develop such systems, it is indispensable to use an environmentally acceptable refrigerant, highly efficient heat exchangers and highly efficient compressors. From this viewpoint, in the present study, the condensation of low GWP refrigerant R1234ze(Z) in vertical channels is investigated experimentally in order to establish optimum design method of plate-fin heat exchanger. Two type of fins are used in the experiment, one is plane fin, another one is serrated fin. In the test channel, the test refrigerant flows downward, while the compressed cooling water flows upward. The local heat transfer characteristics are measured using thermocouples, heat flux sensors and pressure transducers. Also, the experimental results are compared with correlation equation that are composed free convection condensation. As the results, it clarified that heat transfer characteristic in plate fin heat exchanger are different according to difference in fin shapes. The heat transfer characteristics in plate-fin heat exchanger, at low quality area, are phenomenon that is near to free convection condensation.

開催年月日： 2018年6月

記述言語：英語  

開催地：Sapporo, Hokkaido   国名：日本国  

Adsorption dehumidification is gained extensive consideration as an alternative for air conditioning devices. Choosing the appropriate parameters is necessary to improve the performance of the system. In this study, we performed the impact of desorption air temperature on the desiccant ability and thermal performance of desiccant dehumidification (DSCDH) system. The test section was a honeycomb desiccant block made of polymer. Low desorption air temperatures of 35ºC, 45ºC, 55ºC and 65ºC were experimentally investigated under a maintained adsorption air temperature of 20ºC. The mass flow rates of the air and time ratio for desorption and adsorption were remained constant in the value of 0.1 kg/s at 60 minutes for desorption and 120 minutes adsorption. As the results, we found that the thermal performance decreased with the rise of desorption air temperature. In contrary, the dehumidification ability was enhanced with the increased of desorption air temperature. In conclusion, the high desorption air temperature gives insignificant effect on the system performance. On the other hand, it is noteworthy on the dehumidification ability of the system. The thermal performance of the system was found in the values of 0.62, 0.44, 0.35 and 0.29 for desorption temperatures of 35ºC, 45ºC, 55ºC and 65ºC, respectively.

開催年月日： 2018年4月

記述言語：英語  

国名：中華人民共和国  

開催年月日： 2018年4月

記述言語：英語   会議種別：口頭発表（一般）  

国名：中華人民共和国  

開催年月日： 2017年11月

記述言語：英語  

開催地：Lahore   国名：パキスタン・イスラム共和国  

This study investigates the applicability of Maisotsenko cycle evaporative cooling system for climatic conditions of Multan region (Pakistan). The study also provides comparison of (Maisotsenko-cycle) M-Cycle based system with other evaporative cooling systems. An experimental system of M-Cycle has been setup and experiments are conducted for various ambient air conditions. The data has been analyzed, and based on the analyses the performance of the proposed M-cycle system has been investigated for summer (April to September) climatic conditions of Multan region (Pakistan). It has been found that the proposed system can provide the useful air-conditioning effect for Multan climate conditions provided that the ambient air relative humidity does not exceed 60&#37;. The system's applicability is found limited in humid conditions, which is due to nature of M-cycle operation.

開催年月日： 2017年10月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年7月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年7月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年6月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年6月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年5月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年5月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年4月

記述言語：英語   会議種別：口頭発表（一般）  

国名：大韓民国  

開催年月日： 2017年4月

記述言語：英語   会議種別：口頭発表（一般）  

国名：大韓民国  

開催年月日： 2017年4月

記述言語：英語   会議種別：口頭発表（一般）  

国名：大韓民国  

開催年月日： 2017年4月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年3月

記述言語：英語   会議種別：口頭発表（一般）  

国名：大韓民国  

開催年月日： 2017年3月

記述言語：英語   会議種別：口頭発表（一般）  

国名：大韓民国  

開催年月日： 2017年3月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2017年3月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年11月

記述言語：日本語  

国名：日本国  

開催年月日： 2016年9月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：インドネシア共和国  

開催年月日： 2016年6月 - 2016年7月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年6月 - 2016年7月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年6月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年5月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年5月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年5月

記述言語：英語  

開催地：Taipei   国名：台湾  

The study investigated a highly effective humidifier employing the Maisotsenko-Cycle heat and mass recovery structure. The performance of the proposed humidifier is predicted by simulation and humidifying capacity was predicted.

開催年月日： 2016年5月

記述言語：英語  

開催地：Taipei   国名：台湾  

In this study, adsorption characteristics of ethanol onto consolidated composite adsorbents have been investigated experimentally. The prepared consolidated composites are combinations of highly porous activated carbon powder namely Maxsorb III, expanded graphite (EG) and binder with judiciously selected mass ratios. Samples with different packing densities and different compositions have been prepared. Adsorption equilibrium uptakes of ethanol onto the prepared samples have been measured. Experiments have been conducted across assorted adsorption temperatures that are useful for the operation of adsorption chillers. The Dubinin-Astakhov (D-A) and the Dubinin-Radushkevich (D-R) equations have been used to fit the adsorption isotherm data. Thermal conductivities of the prepared composites have been measured using a microflash apparatus. Results showed that the thermal conductivities of prepared samples are significantly higher than those of activated carbon powders.

開催年月日： 2016年5月

記述言語：英語  

開催地：Taipei   国名：台湾  

This study presents 2D-axisymmetric heat and mass transfer simulations of a finned tube adsorber employing activated carbon-ethanol as the adsorbent-refrigerant pair. The simulation is carried out with Ansys-Fluent v16.2 and the mathematical model consists of mass, momentum and energy conservation equations as well as confirmed adsorption isotherms and adsorption kinetics from measured experimental data. The simulated temperatures at different adsorbent thicknesses agreed fairly with those measured in an adsorption chiller setup in our laboratory. Moreover performance investigation is performed for heating, cooling and evaporation temperature of 80, 30 and 15 °C, respectively. The cooling capacity reached 245.9 W/kgAC whereas COP is found to be 0.42. The CFD simulation will allow design and performance optimization of the finned tube adsorber for adsorption chiller applications. It can be extended also to different absorber-heat exchanger designs and different adsorbent-refrigerant pairs.

開催年月日： 2016年4月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2016年3月

記述言語：英語  

開催地：Hammamet   国名：チュニジア共和国  

Adsorption cooling systems (ACS) are feasible alternative to vapor compression cooling system as they employ natural and benign refrigerants and could be driven by solar energy or waste heat. Performance optimization of ACS could be carried out using CFD simulations with lower cost and faster time comparing to experimental testing. One of the crucial parameters to obtain reliable CFD simulation results is the diffusion time constant of adsorption rate equation estimated from experimental data. This study presents transient CFD simulations of ethanol adsorption onto activated carbon powder of type Maxsorb III carried out by Ansys-Fluent v14.5 software using 2D-axisymmetric geometry. The mathematical model consists of mass, momentum and energy conservation equations as well as adsorption isotherm and adsorption kinetic equations implemented via user defined functions (UDFs). The conditions used were same as those employed in gravimetric adsorption analyzer that is 30°C, 2.25 kPa and 3.32 kPa for temperature, initial and inlet pressures, respectively. Through multiple CFD simulations, we estimated the appropriate diffusion time constant of non-isothermal linear driving force (LDF) equation which led to simulated adsorption uptakes agreeing fairly with those measured experimentally. The mathematical model employing non-isothermal LDF equation could be implemented to simulate the heat and mass transfer in large scale adsorption/desorption bed and to optimize the performance of activated carbon-ethanol based adsorption cooling system.

開催年月日： 2015年10月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2015年10月

記述言語：英語   会議種別：口頭発表（一般）  

国名：台湾  

開催年月日： 2015年10月

記述言語：英語   会議種別：口頭発表（一般）  

国名：台湾  

開催年月日： 2015年10月

記述言語：英語   会議種別：口頭発表（一般）  

国名：台湾  

開催年月日： 2015年9月

記述言語：英語  

開催地：Dhaka   国名：バングラデシュ人民共和国  

To provide thermal comfort to the human being many types of cooling technologies are available in the market. These technologies are more essential in the region where the average ambient temperature is high. But every system has some limitations especially for environmental aspect and energy consumption. Open literature shows the available commercial cooling technology used almost 45&#37; of electricity consumed in a house. To keep the system running a lot of fossil fuels need to be burned as a result the volume of greenhouse gases into the air increases. This study introduces a new technology which is emerging as viable alternatives of conventional vapor-compression systems and is known as adsorption cooling system. This system is environment friendly since it uses natural refrigerants and it is driven by low temperature waste heat or solar energy that is why it can solve the existing challenge of global warming and energy crisis.

開催年月日： 2015年8月

記述言語：英語  

開催地：Yokohama   国名：日本国  

Adsorption cooling systems are gaining more interest because of their energy savings and environment protection. Therefore, simulations of heat and mass transfers in the adsorbing/desorbing bed, main component of the system are necessary to achieve more favorable design and to improve the performance. This paper presents computational fluid dynamics (CFD) transient simulation of finned tube type adsorber/desorber bed at operating conditions of adsorption cooling system. Activated carbon powder (ACP) of type Maxsorb III was packed between the fins and ethanol was used as refrigerant. The model uses linear driving force kinetic and diffusion equation, in addition to mass, momentum and energy conservation equations. Simulation results show that temperature and pressure profiles agree fairly with experimental data at lower adsorbent thicknesses. Morover, we found that adsorption kinetics restricted the amount adsorbed to 45&#37; of possible amount for adsorption/desorption time of 350 s. This study validated the mathematical model of the finned tube type adsorber/desorber bed and will permits, in the future, to evaluate and to enhance the performance of air-conditioning and refrigeration based adsorption systems.

開催年月日： 2015年8月

記述言語：英語  

開催地：Yokohama   国名：日本国  

開催年月日： 2015年8月

記述言語：英語  

開催地：Yokohama   国名：日本国  

Water vapor adsorption isotherm taxonomy of silica-gel based type-linear (fictitious), and four adsorbents enabling type-I, II, III, and V isotherms by means of International Union of Pure and Applied Chemistry (IUPAC) classification, are studied for desiccant air-conditioning (AC) applications. Ideal temperature and humidity zones for various AC applications are drawn on psychometric charts. Published adsorption data for studied adsorbents are fitted with the appropriate adsorption models. Ideal desiccant AC cycle is evaluated for AC applications and steady-state cycled moisture is estimated by means of adsorption isobars. Typelinear adsorption isotherm gives the maximum steady-state dehumidification performance for AC in industrial processes of matches manufacturing/drying/storage, rubber dipped goods storage, and photo studio drying room. However, adsorbents enabling type-V isotherm are found the optimum adsorbents for tobacco stemming/stripping/softening and optical lenses grinding. For industrial process-dipped surgical articles; adsorbents enabling type-I, type-II, and type-linear isotherms are resulted the optimum adsorbents under conditions of low (< 68°C), medium (68°C-87°C), and high (> 87°C) temperature regeneration, respectively.