| 宮崎 隆彦（みやざき たかひこ） | データ更新日：2023.11.27 |
教授 ／
総合理工学研究院
環境理工学部門
流動熱工学
| 1. | Budi Kristiawan, Ahmad Imam Rifa'i, Koji Enoki, Agung Tri Wijayanta, Takahiko Miyazaki, Enhancing the thermal performance of TiO2/water nanofluids flowing in a helical microfin tube, POWDER TECHNOLOGY, 10.1016/j.powtec.2020.08.020, 376, 254-262, 2020.10, 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% were respectively 73%, 77%, and 80% 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.. |
| 2. | Budi Kristiawan, Ahmad Imam Rifa'i, Koji Enoki, Agung Tri Wijayanta, Takahiko Miyazaki, Enhancing the thermal performance of TiO |
| 3. | Skander Jribi, Boutheina Zallama, Takahiko Miyazaki, CFD Simulation of CO |
| 4. | Uthpara Perera, Kyaw Thu, Takahiko Miyazaki, Naoya Sakoda, Yukihiro Higashi, Saturation pressure measurements of the new refrigerant HFO1132(E), Proceedings of 2nd Conference on HFOs and Low GWP blends, 10.18462/iir.HFO.2021.1023, 12-19, 2021.06. |
| 5. | Takahiko Miyazaki, Koji Enoki, Joon Ahn, Special Issue on Sciences and Innovations in Heat Pump/Refrigeration: Volume II, Applied Sciences (Switzerland), 10.3390/app122010630, 12, 20, 2022.10. |
| 6. | Kosei Takezato, Shou Senba, Takahiko Miyazaki, Nobuo Takata, Yukihiro Higashi, Kyaw Thu, Heat Pump Cycle Using Refrigerant Mixtures of HFC32 and HFO1234yf, Heat Transfer Engineering, 10.1080/01457632.2020.1776997, 42, 13-14, 1097-1106, 2020.06, 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%) 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% 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.. |
| 7. | Colombatantirige Uthpala Amoda Perera, Nobuo Takata, Takahiko Miyazaki, Yukihiro Higashi, Bidyut Baran Saha, Kyaw Thu, Exergy Investigation of R410A as a ‘Drop In’ Refrigerant in a Water-Cooled Mechanical Vapor Compression Cycle, Heat Transfer Engineering, 10.1080/01457632.2020.1776990, 42, 13-14, 1069-1086, 2020.06, 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% of full capacity. The heat exchanger overall heat transfer coefficients showed varying trends, whilst the exergy destruction was as expected highest for the compressor.. |
| 8. | Muhammad Khalid, Muhammad H. Mahmood, Muhammad Sultan, Muhammad N. Ashraf, Takahiko Miyazaki, Zero-Energy Cool Chamber for Tomato Storage, Green Energy and Technology, 10.1007/978-3-030-86394-4_5, 85-100, 2021.12, 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%. 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.. |
| 9. | Uthpala Perera, Nobuo Takata, Takahiko Miyazaki, Yukihiro Higashi, Kyaw Thu, The exergy investigation of a mechanical vapor compression chiller for cooling using r410a, Evergreen, 10.5109/4372281, 8, 1, 213-220, 2021.03, 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.. |
| 10. | Muhammad H. Mahmood, Muhammad Sultan, Takahiko Miyazaki, Maisotsenko-Cycle Assisted Desiccant Dehumidification System Configurations for Agricultural Product Storage, Green Energy and Technology, 10.1007/978-3-030-86394-4_1, 1-17, 2021.12, 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.. |
| 11. | Y. T. Abirham, K. Thu, T. Miyazaki, F. Mikšík, Investigation of a Thermal Power Pumping cycle system using alternative working fluids, International Journal of Sustainable Energy, 10.1080/14786451.2021.1924717, 41, 3, 215-234, 2021.05, 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.. |
| 12. | Yang Changru, Nobuo Takata, Kyaw Thu, Takahiko Miyazaki, How lubricant plays a role in the heat pump system, Evergreen, 10.5109/4372279, 8, 1, 198-203, 2021.03, 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.. |
| 13. | Chairunnisa, K. Thu, T. Miyazaki, K. Nakabayashi, J. Miyawaki, A. T. Wij Ayanta, F. Rahmawati, Highly microporous activated carbon from acorn nutshells and its performance in water vapor adsorption, Evergreen, 10.5109/4372285, 8, 1, 249-254, 2021.03, 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% 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.. |
| 14. | Muhammad N. Ashraf, Muhammad H. Mahmood, Muhammad Sultan, Muhammad Khalid, Takahiko Miyazaki, Evaporative and Desiccant Air-Conditioning Systems for Wet Markets, Green Energy and Technology, 10.1007/978-3-030-86394-4_6, 101-121, 2021.12, 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.. |
| 15. | Hafiz S. Ullah, Muhammad Sultan, Muhammad H. Mahmood, Hadeed Ashraf, Muhammad Ishaq, Takahiko Miyazaki, Evaporative Cooling and Desiccant Dehumidification Air Conditioning Options for Livestock Thermal Comfort, Green Energy and Technology, 10.1007/978-3-030-86394-4_3, 43-63, 2021.12, 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.. |
| 16. | Muhammad Ishaq, Muhammad Sultan, Muhammad Aleem, Muhammad Bilal, Hafiz S. Ullah, Muhammad H. Mahmood, Takahiko Miyazaki, Desiccant Dehumidification System for Storage of Fruits and Vegetables, Green Energy and Technology, 10.1007/978-3-030-86394-4_4, 65-83, 2021.12, 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.. |
| 17. | Muhammad Aleem, Muhammad Sultan, Muhammad H. Mahmood, Takahiko Miyazaki, Desiccant Dehumidification Cooling System for Poultry Houses in Multan (Pakistan), Green Energy and Technology, 10.1007/978-3-030-86394-4_2, 19-42, 2021.12, 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.. |
| 18. | Y. T. Abirham, K. Thu, T. Miyazaki, N. Takata, Comparative study of thermal water pumping cycles, Evergreen, 10.5109/4372284, 8, 1, 239-248, 2021.03, 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.. |
| 19. | Budi Kristiawan, Koji Enoki, Wibawa Endra Juwana, Rendy Adhi Rachmanto, Agung Tri Wijayanta, Takahiko Miyazaki, Simulation-based assessment of the thermal-hydraulic performance of titania-based nanofluids in a circular-mini-channel tube, International Journal of Ambient Energy, 10.1080/01430750.2022.2085797, 43, 1, 8022-8035, 2022.06, 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.%. 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% was observed for nanoparticles with a concentration of 5 vol.% at the Reynolds number of about 1500.. |
| 20. | Yemanebirhan Abirham, Frantisek Mikšík, Kyaw Thu, Takahiko Miyazaki, Experimental investigation of a thermally driven pumping system for a potential application with a microgrid system for rural communities, Journal of Thermal Science and Technology, 10.1299/jtst.21-00323, 17, 1, 2022.01, 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% of the total pumped water (13 – 27 m3) would be available for agricultural and other purposes while only 6 – 13% 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.. |
| 21. | Muhammad Sultan, Muhammad Aleem, Takahiko Miyazaki, Energy-Efficient Humidity Pump System for Poultry Houses, Green Energy and Technology, 10.1007/978-3-030-90720-4_16, 431-457, 2022.01, 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.. |
| 22. | Hao Yu, Sang won Seo, František Mikšík, Kyaw Thu, Takahiko Miyazaki, Kim Choon Ng, Effects of temperature and humidity ratio on the performance of desiccant dehumidification system under low-temperature regeneration, Journal of Thermal Analysis and Calorimetry, 10.1007/s10973-022-11368-7, 2022.05, 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.. |
| 23. | Sagar Saren, Sourav Mitra, Takahiko Miyazaki, Kim Choon Ng, Kyaw Thu, Adsorption heat transformer cycle using multiple adsorbent + water pairs for waste heat upgrade, Journal of Thermal Analysis and Calorimetry, 10.1007/s10973-022-11350-3, 2022.04, 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.. |
| 24. | Chairunnisa Zainuri Chairunnisa, Frantisek Miksik, Takahiko Miyazaki, Kyaw Thu, Jin Miyawaki, Koji Nakabayashi, Agung Tri Wijayanta, Fitria Rahmawati, Theoretical dehumidification capacity of acorn nutshell-based activated carbon under two Asian urban cities’ ambient air condition, International Journal of Refrigeration, 10.1016/j.ijrefrig.2021.08.012, 131, 137-145, 2021.11, 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.. |
| 25. | Chairunnisa, Frantisek Miksik, Takahiko Miyazaki, Kyaw Thu, Jin Miyawaki, Koji Nakabayashi, Agung Tri Wijayanta, Fitria Rahmawati, Development of biomass based-activated carbon for adsorption dehumidification, Energy Reports, 10.1016/j.egyr.2021.09.003, 7, 5871-5884, 2021.11, 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.. |
| 26. | Nadia Riaz, Muhammad Sultan, Takahiko Miyazaki, Muhammad Wakil Shahzad, Muhammad Farooq, Uzair Sajjad, Yasir Niaz, A review of recent advances in adsorption desalination technologies, International Communications in Heat and Mass Transfer, 10.1016/j.icheatmasstransfer.2021.105594, 128, 2021.11, 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%, along with an augmented water production rate from 60% 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$0.2/m3.. |
| 27. | Mansoor Abdul Aziz, Jie Lin, František Mikšík, Takahiko Miyazaki, Kyaw Thu, The second law analysis of a humidification-dehumidification desalination system using M-cycle, Sustainable Energy Technologies and Assessments, 10.1016/j.seta.2022.102141, 52, 2022.08, 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 %. 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 %.. |
| 28. | Kohei Matsui, Jie Lin, Kyaw Thu, Takahiko Miyazaki, On the performance improvement of an inverted Brayton Cycle using a regenerative heat and mass exchanger, Energy, 10.1016/j.energy.2022.123726, 249, 2022.06, 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% to 14.36% and specific work output from 10.38 to 12.46 kJ/kg equivalent to 76.63% and 20.1% 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.. |
| 29. | Uthpala A. Perera, Naoya Sakoda, Takahiko Miyazaki, Kyaw Thu, Yukihiro Higashi, Measurements of saturation pressures for the novel refrigerant R1132(E)✰, International Journal of Refrigeration, 10.1016/j.ijrefrig.2021.12.014, 135, 148-153, 2022.03, 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%. 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%.. |
| 30. | Sagar Saren, Sourav Mitra, Takahiko Miyazaki, Kim Choon Ng, Kyaw Thu, A novel hybrid adsorption heat transformer – multi-effect distillation (AHT-MED) system for improved performance and waste heat upgrade, Applied Energy, 10.1016/j.apenergy.2021.117744, 305, 2022.01, 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.. |
| 31. | Jaedeok Ko, Kyaw Thu, Takahiko Miyazaki, Transient analysis of an electric vehicle air-conditioning system using CO |
| 32. | Mojtaba Purjam, Kyaw Thu, Takahiko Miyazaki, Thermodynamic modeling of an improved transcritical carbon dioxide cycle with ejector: Aiming low-temperature refrigeration, Applied Thermal Engineering, 10.1016/j.applthermaleng.2020.116531, 188, 2021.04, 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% less compression ratio than its R744 counterparts.. |
| 33. | Khawar Shahzad, Muhammad Sultan, Muhammad Bilal, Hadeed Ashraf, Muhammad Farooq, Takahiko Miyazaki, Uzair Sajjad, Imran Ali, Muhammad I. Hussain, Experiments on energy‐efficient evaporative cooling systems for poultry farm application in Multan (Pakistan), Sustainability (Switzerland), 10.3390/su13052836, 13, 5, 1-22, 2021.03, 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.. |
| 34. | Sangwon Seo, František Mikšík, Yuta Maeshiro, Kyaw Thu, Takahiko Miyazaki, Performance evaluation of an adsorption heat pump system using msc‐30/r1234yf pair with the impact of thermal masses, Applied Sciences (Switzerland), 10.3390/app11052279, 11, 5, 1-25, 2021.03, 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%. 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.. |
| 35. | Shazia Noor, Hadeed Ashraf, Ghulam Hussain, Muhammad Sultan, Takahiko Miyazaki, Aamir Shakoor, Muhammad H. Mahmood, Mahmood Riaz, Spatiotemporal investigation of evaporative cooling options for greenhouse air-conditioning application in Pakistan, Fresenius Environmental Bulletin, 30, 3, 2858-2870, 2021.03, 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.. |
| 36. | S. Seo, H. Kawakami, F. Miksik, N. Takata, K. Thu, T. Miyazaki, Thermodynamic analysis and impact of thermal masses on adsorption cycles using MaxsorbIII/R245fa and SAC-2/R245fa pairs, International Journal of Refrigeration, 10.1016/j.ijrefrig.2020.12.005, 123, 52-62, 2021.03, 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.. |
| 37. | Mojtaba Purjam, Kyaw Thu, Takahiko Miyazaki, Thermodynamic feasibility evaluation of a novel low-temperature ejector-based trans-critical r744 refrigeration cycle, Evergreen, 10.5109/4372280, 8, 1, 204-212, 2021.03, 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.. |
| 38. | Fitria Rahmawati, Arikasuci Fitonna Ridassepri, Chairunnisa, Agung Tri Wijayanta, Koji Nakabayashi, Jin Miyawaki, Takahiko Miyazaki, Carbon from bagasse activated with water vapor and its adsorption performance for methylene blue, Applied Sciences (Switzerland), 10.3390/app11020678, 11, 2, 1-16, 2021.01, 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.. |
| 39. | Kyaw Thu, Kosei Takezato, Nobuo Takata, Takahiko Miyazaki, Yukihiro Higashi, Drop-in experiments and exergy assessment of HFC-32/HFO-1234yf/R744 mixture with GWP below 150 for domestic heat pumps, International Journal of Refrigeration, 10.1016/j.ijrefrig.2020.10.009, 121, 289-301, 2021.01, 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%) 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%, 37.8%, and 43.3% 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.. |
| 40. | Jaedeok Ko, Kyaw Thu, Takahiko Miyazaki, Investigation of a cascaded CO |
| 41. | Kyaw Thu, Kosei Takezato, Nobuo Takata, Takahiko Miyazaki, Yukihiro Higashi, Performance evaluation of a heat pump system using an HFC32/HFO1234yf blend with GWP below 150 for heating applications, Applied Thermal Engineering, 10.1016/j.applthermaleng.2020.115952, 182, 2021.01, 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%, 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% 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.. |
| 42. | Faizan Shabir, Muhammad Sultan, Shazia Noor, Ghulam Hussain, Takahiko Miyazaki, Aamir Shakoor, Rabia Kanwal, Yasir Niaz, Muhammad A. Imran, Muhammad U. Khalid, Study on adsorption equilibrium of adsorbent-refrigerant pairs for adsorption cooling system application, Fresenius Environmental Bulletin, 30, 1, 216-224, 2021.01, 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.. |
| 43. | Changru Yang, Sangwon Seo, Nobuo Takata, Kyaw Thu, Takahiko Miyazaki, The life cycle climate performance evaluation of low-GWP refrigerants for domestic heat pumps, International Journal of Refrigeration, 10.1016/j.ijrefrig.2020.09.020, 121, 33-42, 2021.01, 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.. |
| 44. | Chairunnisa, František Mikšík, Takahiko Miyazaki, Kyaw Thu, Jin Miyawaki, Koji Nakabayashi, Agung Tri Wijayanta, Fitria Rahmawati, Enhancing water adsorption capacity of acorn nutshell based activated carbon for adsorption thermal energy storage application, Energy Reports, 10.1016/j.egyr.2020.11.038, 6, 255-263, 2020.12, 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.. |
| 45. | B. Kiran Naik, Mullapudi Joshi, P. Muthukumar, Muhammad Sultan, Takahiko Miyazaki, Redmond R. Shamshiri, Hadeed Ashraf, Investigating solid and liquid desiccant dehumidification options for room air-conditioning and drying applications, Sustainability (Switzerland), 10.3390/su122410582, 12, 24, 1-22, 2020.12, 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.. |
| 46. | František Mikšík, Takahiko Miyazaki, Kyaw Thu, Adsorption isotherm modelling of water on nano-tailored mesoporous silica based on distribution function, Energies, 10.3390/en13164247, 13, 6, 2020.08, 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. |
| 47. | Jaedeok Ko, Nobuo Takata, Kyaw Thu, Takahiko Miyazaki, Dynamic modeling and validation of a carbon dioxide heat pump system, Evergreen, 7, 2, 172-194, 2020.06, 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.. |
| 48. | Agung Tri Wijayanta, Indri Yaningsih, Wibawa Endra Juwana, Muhammad Aziz, Takahiko Miyazaki, Effect of wing-pitch ratio of double-sided delta-wing tape insert on the improvement of convective heat transfer, International Journal of Thermal Sciences, 10.1016/j.ijthermalsci.2020.106261, 151, 2020.05, [URL], 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% 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.. |
| 49. | Kohei Matsui, Kyaw Thu, Takahiko Miyazaki, A hybrid power cycle using an inverted Brayton cycle with an indirect evaporative device for waste-heat recovery, Applied Thermal Engineering, 10.1016/j.applthermaleng.2020.115029, 170, 2020.04, [URL], 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%) 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.. |
| 50. | Faizan Shabir, Muhammad Sultan, Takahiko Miyazaki, Bidyut B. Saha, Ahmed Askalany, Imran Ali, Yuguang Zhou, Riaz Ahmad, Redmond R. Shamshiri, Recent updates on the adsorption capacities of adsorbent-adsorbate pairs for heat transformation applications, Renewable and Sustainable Energy Reviews, 10.1016/j.rser.2019.109630, 119, 2020.03, [URL], 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.. |
| 51. | Indri Yaningsih, Agung Tri Wijayanta, Kyaw Thu, Takahiko Miyazaki, Influence of phase change phenomena on the performance of a desiccant dehumidification system, Applied Sciences (Switzerland), 10.3390/app10030868, 10, 3, 2020.02, [URL], 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% 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.. |
| 52. | František Mikšík, Takahiko Miyazaki, Miki Inada, Detailed investigation on properties of novel commercial mesoporous silica materials, Microporous and Mesoporous Materials, 10.1016/j.micromeso.2019.109644, 289, 2019.11, [URL], 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.. |
| 53. | Muhammad Hamid Mahmood, Muhammad Sultan, Takahiko Miyazaki, Study on water-vapor adsorption onto polymer and carbon based adsorbents for air-conditioning applications, Evergreen, 6, 3, 215-224, 2019.09, 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.. |
| 54. | Kyaw THU, Nami TAKEDA, Takahiko MIYAZAKI, Bidyut Baran SAHA, Shigeru KOYAMA, Tomohiro MARUYAMA, Shinnosuke MAEDA, Toru KAWAMATA, Étude expérimentale sur la performance d'un système à adsorption utilisant une paire Maxsorb III/éthanol, International Journal of Refrigeration, 10.1016/j.ijrefrig.2018.06.009, 105, 148-157, 2019.09, [URL], 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.. |
| 55. | Budi Kristiawan, Agung Tri Wijayanta, Koji Enoki, Takahiko Miyazaki, Muhammad Aziz, Heat transfer enhancement of TiO2/water nanofluids flowing inside a square minichannel with a microfin structure A numerical investigation, Energies, 10.3390/en12163041, 12, 16, 2019.08, [URL], 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.%. 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.%. 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%. 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.. |
| 56. | Frantisek Miksik, Takahiko Miyazaki, Material selection and properties for adsorption heat storage perspectivity of TMPS series mesoporous silica nano-materials, Adsorption, 10.1007/s10450-019-00107-4, 25, 6, 1137-1145, 2019.08, [URL], 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.. |
| 57. | Takahiko Miyazaki, Special issue on sciences in heat pump and refrigeration, Applied Sciences (Switzerland), 10.3390/app9112385, 9, 11, 2019.06, [URL]. |
| 58. | Ahmad Imam Rifa'I, Muhammad Faisal Hasan, Budi Kristiawan, Agung Tri Wijayanta, Takahiko Miyazaki, Kyaw Thu, Koji Enoki, Experimental study of heat transfer enhancement and pressure drop using TiO |
| 59. | Shazia Hanif, Muhammad Sultan, Takahiko Miyazaki, Effect of relative humidity on thermal conductivity of zeolite-based adsorbents Theory and experiments, Applied Thermal Engineering, 10.1016/j.applthermaleng.2018.12.144, 150, 11-18, 2019.03, [URL], 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.. |
| 60. | Muhammad H. Mahmood, Muhammad Sultan, Takahiko Miyazaki, Experimental evaluation of desiccant dehumidification and air-conditioning system for energy-efficient storage of dried fruits, Building Services Engineering Research and Technology, 10.1177/0143624419893660, 2019.01, [URL], 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.. |
| 61. | Shazia Hanif, Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama, Investigation of energy-efficient solid desiccant system for the drying of wheat grains, International Journal of Agricultural and Biological Engineering, 10.25165/j.ijabe.20191201.3854, 12, 1, 221-228, 2019.01, [URL], 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.. |
| 62. | Muhammad Hamid Mahmood, Muhammad Sultan, Takahiko Miyazaki, Significance of Temperature and Humidity Control for Agricultural Products Storage Overview of Conventional and Advanced Options, International Journal of Food Engineering, 10.1515/ijfe-2019-0063, 2019.01, [URL], 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.. |
| 63. | Muhammad H. Mahmood, Muhammad Sultan, Takahiko Miyazaki, Solid desiccant dehumidification-based air-conditioning system for agricultural storage application Theory and experiments, Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 10.1177/0957650919869503, 2019.01, [URL], 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.. |
| 64. | Muhammad Sultan, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Hyun Sig Kil, Koji Nakabayashi, Jin Miyawaki, Seong-Ho Yoon, Adsorption of Difluoromethane (HFC-32) onto phenol resin based adsorbent Theory and experiments, International Journal of Heat and Mass Transfer, 10.1016/j.ijheatmasstransfer.2018.07.097, 127, 348-356, 2018.12, [URL], 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.. |
| 65. | Agung Tri Wijayanta, Indri Yaningsih, Muhammad Aziz, Takahiko Miyazaki, Shigeru Koyama, Double-sided delta-wing tape inserts to enhance convective heat transfer and fluid flow characteristics of a double-pipe heat exchanger, Applied Thermal Engineering, 10.1016/j.applthermaleng.2018.09.009, 145, 27-37, 2018.12, [URL], 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% 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.. |
| 66. | Indri Yaningsih, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Thermal hydraulic characteristics of turbulent single-phase flow in an enhanced tube using louvered strip insert with various slant angles, International Journal of Thermal Sciences, 10.1016/j.ijthermalsci.2018.08.025, 134, 355-362, 2018.12, [URL], 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% 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.. |
| 67. | František Mikšík, Jan Skolil, Josef Kotlík, Čáslavský Josef, Takahiko Miyazaki, Marie Kačírková, Helena Pučková, Viscosities, Densities, and Refractive Indices of Aqueous Propane-1,3-diol, Journal of Chemical and Engineering Data, 10.1021/acs.jced.8b00403, 63, 12, 4350-4367, 2018.12, [URL], 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.. |
| 68. | Indri Yaningsih, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Analysis of heat and mass transfer characteristics of desiccant dehumidifier system with honeycomb configuration, Applied Thermal Engineering, 10.1016/j.applthermaleng.2018.08.066, 144, 658-669, 2018.11, [URL], 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 (Tads) 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.. |
| 69. | Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Remarque sur la mauvaise distribution du frigorigène R134a en écoulement dans un évaporateur à collecteur, International Journal of Refrigeration, 10.1016/j.ijrefrig.2018.08.003, 95, 1-9, 2018.11, [URL], 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.. |
| 70. | Shinnosuke Maeda, Kyaw Thu, Tomohiro Maruyama, Takahiko Miyazaki, Critical review on the developments and future aspects of adsorption heat pumps for automobile air conditioning, Applied Sciences (Switzerland), 10.3390/app8112061, 8, 11, 2018.10, [URL], 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.. |
| 71. | Takahiko Miyazaki, Evaporative heat exchangers, Handbook of Thermal Science and Engineering, 10.1007/978-3-319-26695-4_22, 1521-1533, 2018.07, [URL], 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.. |
| 72. | Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama, Optimization of adsorption isotherm types for desiccant air-conditioning applications, Renewable Energy, 10.1016/j.renene.2018.01.045, 121, 441-450, 2018.06, [URL], 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 (< 68 °C), medium (68°C-87 °C), and high (> 87 °C) regeneration temperatures, respectively.. |
| 73. | Indri Yaningsih, Muhammad Hamid Mahmood, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Experimental study on dehumidification technology using honeycomb desiccant block, Evergreen, 10.5109/1936212, 5, 2, 11-18, 2018.06, [URL], 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%. Hence, the experimental methods were reliable to conduct the further experiments.. |
| 74. | Budi Kristiawan, Budi Santoso, Agung Tri Wijayanta, Muhammad Aziz, Takahiko Miyazaki, Heat transfer enhancement of TiO2/water nanofluid at laminar and turbulent flows A numerical approach for evaluating the effect of nanoparticle loadings, Energies, 10.3390/en11061584, 11, 6, 2018.06, [URL], 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% for nanoparticle loadings of 0.24, 0.60, and 1.18 vol.%, respectively. On the other hand, for turbulent flow, the corresponding heat transfer increases were 4.04, 10.33, and 21.87%.. |
| 75. | Khanam Marzia, Muhammad Faisal Hasan, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Key factors of solar energy progress in Bangladesh until 2017, Evergreen, 10.5109/1936220, 5, 2, 78-85, 2018.06, [URL], 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% 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%), 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.. |
| 76. | Marzia Khanam, Skander Jribi, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Numerical investigation of small-scale adsorption cooling system performance employing activated carbon-ethanol pair, Energies, 10.3390/en11061499, 11, 6, 2018.06, [URL], 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% and 7.88%, 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.. |
| 77. | Muhammad Faisal Hasan, Md. Sayeed Ur Rahim Mahadi, Takahiko Miyazaki, Shigeru Koyama, Kyaw Thu, Exergy analysis of serpentine thermosyphon solar water heater, Applied Sciences (Switzerland), 10.3390/app8030391, 8, 3, 2018.03, [URL], 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%. 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%, whereas approximately 77% 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.. |
| 78. | Muhammad Sultan, Takahiko Miyazaki, Muhammad H. Mahmood, Zahid M. Khan, Solar assisted evaporative cooling based passive air-conditioning system for agricultural and livestock applications, Journal of Engineering Science and Technology, 13, 3, 693-703, 2018.03, 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.. |
| 79. | Shazia Hanif, Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama, Steady-state investigation of desiccant drying system for agricultural applications, Evergreen, 5, 1, 33-42, 2018.03, 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.. |
| 80. | Sofia Fitrina, Budi Kristiawan, Eko Surojo, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Influence of minimum quantity lubrication with Al2O3 nanoparticles on cutting parameters in drilling process, 3rd International Conference on Industrial Mechanical, Electrical, and Chemical Engineering, ICIMECE 2017 3rd International Conference on Industrial Mechanical, Electrical, and Chemical Engineering, 10.1063/1.5024115, 1931, 2018.02, [URL], 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.. |
| 81. | Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama, Zahid M. Khan, Performance evaluation of hydrophilic organic polymer sorbents for desiccant air-conditioning applications, Adsorption Science and Technology, 10.1177/0263617417692338, 36, 1-2, 311-326, 2018.02, [URL], 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.. |
| 82. | Indri Yaningsih, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, V-cut twisted tape insert effect on heat transfer enhancement of single phase turbulent flow heat exchanger, 3rd International Conference on Industrial Mechanical, Electrical, and Chemical Engineering, ICIMECE 2017 3rd International Conference on Industrial Mechanical, Electrical, and Chemical Engineering, 10.1063/1.5024097, 1931, 2018.02, [URL], 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.. |
| 83. | Sofia Fitrina, Budi Kristiawan, Eko Surojo, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Influence of minimum quantity lubrication with Al2O3 nanoparticles on cutting parameters in drilling process, AIP Conference Proceedings, 10.1063/1.5024115, 1931, 2018.02, 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.. |
| 84. | Indri Yaningsih, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, V-cut twisted tape insert effect on heat transfer enhancement of single phase turbulent flow heat exchanger, AIP Conference Proceedings, 10.1063/1.5024097, 1931, 2018.02, 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.. |
| 85. | Indri Yaningsih, Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Impact of blockage ratio on thermal performance of delta-winglet vortex generators, Applied Sciences (Switzerland), 10.3390/app8020181, 8, 2, 2018.01, [URL], 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% 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.. |
| 86. | Animesh Pal, Hyun-Sig Kil, Sourav Mitra, Kyaw Thu, Bidyut Baran Saha, Seong-Ho Yoon, Jin Miyawaki, Takahiko Miyazaki, Shigeru Koyama, Ethanol adsorption uptake and kinetics onto waste palm trunk and mangrove based activated carbons, APPLIED THERMAL ENGINEERING, 10.1016/j.applthermaleng.2017.04.099, 122, 389-397, 2017.07, [URL], 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.. |
| 87. | Skander Jribi, Takahiko Miyazaki, Bidyut Baran Saha, Animesh Pal, Mohamed M. Younes, Shigeru Koyama, Aref Maalej, Equilibrium and kinetics of CO2 adsorption onto activated carbon, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 10.1016/j.ijheatmasstransfer.2016.12.114, 108, 1941-1946, 2017.05, 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.. |
| 88. | Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Analytical Model of a Combined Adsorption Cooling and Mechanical Vapor Compression Refrigeration System, Heat Transfer Engineering, 10.1080/01457632.2016.1195135, 38, 4, 423-430, 2017.03, [URL], 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.. |
| 89. | Skander Jribi, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Shinnosuke Maeda, Tomohiro Maruyama, CFD simulation and experimental validation of ethanol adsorption onto activated carbon packed heat exchanger, INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID, 10.1016/j.ijrefrig.2016.10.019, 74, 345-353, 2017.02, 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.. |
| 90. | Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Refrigerant distribution in horizontal headers with downward minichannel-branching conduits: Experiment, empirical correlation and two-phase flow pattern map, EXPERIMENTAL THERMAL AND FLUID SCIENCE, 10.1016/j.expthermflusci.2016.09.011, 81, 430-444, 2017.02, [URL], 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.. |
| 91. | Skander Jribi, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Shinnosuke Maeda, Tomohiro Maruyama, Simulation par la mécanique numérique des fluides (CFD) et validation expérimentale de l'adsorption de l’éthanol sur un échangeur de chaleur compact à charbon actif, International Journal of Refrigeration, 10.1016/j.ijrefrig.2016.10.019, 74, 343-351, 2017.02, [URL], 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.. |
| 92. | Agung Tri Wijayanta, 宮崎 隆彦, 小山 繁, Refrigerant distribution in horizontal headers with downward minichannel-branching conduits: Experiment, empirical correlation and two-phase flow pattern map, 81, 430-444, 2017.01. |
| 93. | Takahiko Miyazaki, Jin Miyawaki, Tomonori Ohba, Seong-Ho Yoon, Bidyut Baran Saha, Shigeru Koyama, Study toward high-performance thermally driven air-conditioning systems, 1st International Conference on Engineering, Science and Nanotechnology 2016, ICESNANO 2016 International Conference on Engineering, Science and Nanotechnology 2016, ICESNANO 2016, 10.1063/1.4968250, 1788, 2017.01, [URL], 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.. |
| 94. | Muhammad H. Mahmood, Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama, Valeriy S. Maisotsenko, Overview of the Maisotsenko cycle - A way towards dew point evaporative cooling, RENEWABLE & SUSTAINABLE ENERGY REVIEWS, 10.1016/j.rser.2016.08.022, 66, 537-555, 2016.12, 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.. |
| 95. | Skander Jribi, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Shinnosuke Maeda, Tomohiro Maruyama, Corrected adsorption rate model of activated carbon-ethanol pair by means of CFD simulation, INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID, 10.1016/j.ijrefrig.2016.08.004, 71, 60-68, 2016.11, 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.. |
| 96. | Animesh Pal, Ibrahim I. EI-Sharkawy, Bidyut Baran Saha, Skander Jribi, Takahiko Miyazaki, Shigeru Koyama, Experimental investigation of CO2 adsorption onto a carbon based consolidated composite adsorbent for adsorption cooling application, APPLIED THERMAL ENGINEERING, 10.1016/j.applthermaleng.2016.08.031, 109, 304-311, 2016.10, 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.. |
| 97. | Animesh Pal, Ibrahim I. El-Sharkawy, SAHA BIDYUT BARAN, Khairul Habib, 宮崎 隆彦, 小山 繁, Thermodynamic analysis of adsorption cooling cycle using consolidated composite adsorbents-ethanol pairs, 11, 20, 12234-12238, 2016.10. |
| 98. | Agung Tri Wijayanta, Takahiko Miyazaki, Shigeru Koyama, Liquid-vapor phase distribution in horizontal headers with upward minichannel-branching conduits, EXPERIMENTAL THERMAL AND FLUID SCIENCE, 10.1016/j.expthermflusci.2016.03.021, 76, 264-274, 2016.09, 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.. |
| 99. | Muhammad Sultan, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut B. Saha, Shigeru Koyama, Tomohiro Maruyama, Shinnosuke Maeda, Takashi Nakamura, Water vapor sorption kinetics of polymer based sorbents: Theory and experiments, APPLIED THERMAL ENGINEERING, 10.1016/j.applthermaleng.2016.05.192, 106, 192-202, 2016.08, 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.. |
| 100. | Takahiko Miyazaki, SAHA BIDYUT BARAN, 小山 繁, Analytical Model of a Combined Adsorption Cooling and Mechanical Vapor Compression Refrigeration System, Heat Transfer Engineering, 10.1080/01457632.2016.1195135, 2016.06. |
| 101. | Muhammad Sultan, Muhammad H. Mahmood, 宮崎 隆彦, 小山 繁, Zahid M. Khan, Close and open cycle adsorption kinetics: Development of correlation for desiccant air-conditioning, 35, 1, 1-8, 2016.06. |
| 102. | 中本 大志朗, 宮崎 隆彦, SAHA BIDYUT BARAN, 小山 繁, 活性炭-高圧冷媒系吸着過程における熱物質移動解析シミュレーション, 33, 2, 173-183, 2016.06. |
| 103. | I. Gusti Agung Bagus Wirajati, Yuki Ueda, Atsushi Akisawa, Takahiko Miyazaki, Cycle Optimization on Reheat Adsorption Cycle Applying Fixed Chilled Water Outlet Temperature, HEAT TRANSFER ENGINEERING, 10.1080/01457632.2015.1066650, 37, 7-8, 606-615, 2016.05, 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).. |
| 104. | Bidyut Baran Saha, Takahiko Miyazaki, Selected Papers from the International Symposium on Innovative Materials for Processes in Energy Systems 2013 (IMPRES2013): Part I, HEAT TRANSFER ENGINEERING, 10.1080/01457632.2015.1066645, 37, 7-8, 603-605, 2016.05. |
| 105. | Ibrahim I. El-Sharkawy, Animesh Pal, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, A study on consolidated composite adsorbents for cooling application, APPLIED THERMAL ENGINEERING, 10.1016/j.applthermaleng.2015.12.105, 98, 1214-1220, 2016.04, 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% Maxsorb III, 20% EG, 10% binder) is 0.89 kg kg(-1) which is about 74% 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.. |
| 106. | JRIBI SKANDER, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Shinnosuke Maeda, Tomohiro Maruyama, Non-isothermal adsorption rate model of activated carbon-ethanol pair for solar cooling applications estimated through CFD simulation, Proceedings of the 7th International Renewable Energy Congress, 2016.03. |
| 107. | JRIBI SKANDER, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Shinnosuke Maeda, Tomohiro Maruyama, CFD Simulation of Ethanol Adsorption onto Activated Carbon for Adsorption Cooling Applications, Proceedings of the First Pacific Rim Thermal Engineering Conference, PRTEC-14747, 2016.03. |
| 108. | Muhammad Sultan, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Steady-state investigation of water vapor adsorption for thermally driven adsorption based greenhouse air-conditioning system, RENEWABLE ENERGY, 10.1016/j.renene.2015.09.015, 86, 785-795, 2016.02, 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%, 40% and 20% 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.. |
| 109. | Marzia Khanam, Kazuhide Ito, Takahiko Miyazaki, Simulation of gas cooler of CO2 heat pump water heater for different tube geometries, Proceedings of the 3rd International Workshop on Heat Transfer Advances for Energy Conservation and Pollution Control, Paper ID 1176, 2015.10. |
| 110. | Daishiro Nakamoto, Takahiko Miyazaki, Shigeru Koyama, Bidyut Baran Saha, Study on adsorption characteristics of activated carbon - R 32 pair for heat pump application, Proceedings of the 3rd International Workshop on Heat Transfer Advances for Energy Conservation and Pollution Control, Paper ID 1177, 2015.10. |
| 111. | Fauziah Jerai, Takahiko Miyazaki, Shigeru Koyama, Bidyut Baran Saha, S. Maeda, T. Onda, T. Maruyama, Optimum cycle time for one bed operation of activated carbon-ethanol pair adsorption cooling system, Proceedings of the 3rd International Workshop on Heat Transfer Advances for Energy Conservation and Pollution Control, Paper ID 1215, 2015.10. |
| 112. | Takahiko Miyazaki, Shigeru Koyama, Valeriy S. Maisotsenko, The Maisotsenko Cycle as a Heat and Mass Recovery Device for Co-Generation, Proceedings of the 4th International Conference on Microgeneration and Related Technologies, Paper ID 0088, 2015.10. |
| 113. | 今村 駿斗, Takahiko Miyazaki, I.I. El-Sharkawy, Bidyut Baran Saha, Shigeru Koyama, 球状活性炭とエタノールを用いた吸着式冷凍システムの性能予測, 日本冷凍空調学会論文集, 32, 3, 241-253, 2015.09. |
| 114. | 坂内 正明, Takahiko Miyazaki, スマートキャンパスの運用による大学の二酸化炭素排出抑制−第1報：個別建物の需要特性と外気エンタルピーによる夏期電力需要予測−, 日本冷凍空調学会論文集, 32, 3, 231-240, 2015.09. |
| 115. | JERAI Fauziah, MIYAZAKI Takahiko, SAHA Bidyut Baran, KOYAMA Shigeru, Importance of Pre-cooling and Pre-heating on Performances of One Bed Adsorption Cooling Systems with Activated Carbon-ethanol Pair (創立90周年記念号) -- (特集 再生可能エネルギーと冷凍空調), 日本冷凍空調学会論文集, 10.11322/tjsrae.15-26RE, 32, 3, 381-392, 2015.09, 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. . |
| 116. | Muhammad Sultan, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Valeriy S. Maisotsenko, Steady-state analysis on thermally driven adsorption air-conditioning system for agricultural greenhouses, Procedia Engineering, 118, 185-192, 2015.08. |
| 117. | Muhammad Sultan, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Optimization of adsorption isotherm taxonomy for open-cycle desiccant air-conditioning applications, Proceedings of the 24th IIR International Congress of Refrigeration (ICR2015), E1-Tu-3, 2015.08. |
| 118. | JRIBI SKANDER, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Transient simulation of finned tube type adsorber employing activated carbon-ethanol as adsorbent-refrigerant pair, Proceedings of the 24th IIR International Congress of Refrigeration (ICR2015), B1-We-2b, 2015.08. |
| 119. | Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Adsorption characteristics of ethanol onto promising adsorbents for adsorption cooling applications, Proceedings of the 24th IIR International Congress of Refrigeration (ICR2015), E2-Th-4, 2015.08. |
| 120. | Muhammad Sultan, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, An overview of solid desiccant dehumidification and air conditioning systems, RENEWABLE & SUSTAINABLE ENERGY REVIEWS, 10.1016/j.rser.2015.02.038, 46, 16-29, 2015.06, 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.. |
| 121. | Muhammad Sultan, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut B. Saha, Shigeru Koyama, Tomohiro Maruyama, Shinnosuke Maeda, Takashi Nakamura, Insights of water vapor sorption onto polymer based sorbents, ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY, 10.1007/s10450-015-9663-y, 21, 3, 205-215, 2015.04, 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.. |
| 122. | Abul Fazal Mohammad Mizanur Rahman, Yuki Ueda, Atsushi Akisawa, Takahiko Miyazaki, Bidyut Baran Saha, Study of a silica gel-water-based three-bed dual-mode adsorption cooling cycle, Heat Transfer Research, 10.1615/HeatTransRes.2014007215, 46, 3, 213-232, 2015.03. |
| 123. | Ibrahim I. El-Sharkavvy, Kutub Uddin, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Hyun-Sig Kil, Seong-Ho Yoon, Jin Miyawaki, Adsorption of ethanol onto phenol resin based adsorbents for developing next generation cooling systems, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 10.1016/j.ijheatmasstransfer.2014.10.012, 81, 171-178, 2015.02, 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.. |
| 124. | Bidyut Baran Saha, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Shigeru Koyama, Stefan K. Henninger, Annika Herbst, Christoph Janiak, Ethanol adsorption onto metal organic framework: Theory and experiments, ENERGY, 10.1016/j.energy.2014.11.022, 79, 363-370, 2015.01, 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.. |
| 125. | Hayato Imamura, Takahiko Miyazaki, Ibrahim I. El-Sharkawy, Bidyut Baran Saha, Shigeru Koyama, Dynamic simulation of adsorption heat pumps with surface treated activated carbon-ethanol pairs, Proceedings of the International Workshop on Environment & Engineering 2014, 415, 2014.11. |
| 126. | Tsutomu Sumii, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Study on adsorption heat pump cycles using activated carbon-R32 pair, Proceedings of the International Workshop on Environment & Engineering 2014, 416, 2014.11. |
| 127. | Kutub Uddin, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Hyun-Sig Kil, Jin Miyawaki, Seong-Ho Yoon, Adsorption characteristics of ethanol onto functional activated carbons with controlled oxygen content, APPLIED THERMAL ENGINEERING, 10.1016/j.applthermaleng.2014.03.062, 72, 2, 211-218, 2014.11, 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.. |
| 128. | Muhammad Sultan, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Experimental Study on Carbon Based Adsorbents for Greenhouse Dehumidification, Evergreen - Joint Journal of Novel Carbon Resource Sciences & Green Asia Strategy, 1, 2, 5-11, 2014.09. |
| 129. | Takahiko Miyazaki, Ibrahim I. El-Sharkawy, Bidyut Baran Saha, Shigeru Koyama, Optimized Performance of One-Bed Adsorption Cooling System, Proceedings of the 15th International Refrigeration and Air Conditioning Conference at Purdue, 2429, 2014.07. |
| 130. | Kutub Uddin, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Thermodynamic Analysis of Adsorption Refrigeration Cycles Using Parent and Surface Treated Maxsorb III/Ethanol Pairs, Proceedings of the 15th International Refrigeration and Air Conditioning Conference at Purdue, 2456, 2014.07. |
| 131. | Fauziah Jerai, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Shinnosuke Maeda, Tadayoshi Onda, Tomohiro Maruyama, ANALYSIS ON ADSORBER PERFORMANCE FOR THERMALLY DRIVEN CHILLERS, Proceedings of the Grand Renewable Energy 2014, P-Th-38, 2014.07. |
| 132. | Ibrahim I. El-Sharkawy, Kutub Uddin, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Jin Miyawaki, Seong-Ho Yoon, Adsorption of ethanol onto parent and surface treated activated carbon powders, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 10.1016/j.ijheatmasstransfer.2014.02.046, 73, 445-455, 2014.06, 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.. |
| 133. | Takahiko Miyazaki, Bidyut Baran Saha, Ibrahim I. El-Sharkawy, Shigeru Koyama, Performancesimulationofadsorptionrefrigeration/heatpumpwithsilicagel-waterandactivatedcarbon-ethanol combinations, Proceedings of the 7th Asian Conference on Refrigeration and Air Conditioning, 503, 2014.05. |
| 134. | Muhammad Sultan, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, A study on adsorption of water onto carbon based adsorbents, Proceedings of the 7th Asian Conference on Refrigeration and Air Conditioning, 534, 2014.05. |
| 135. | Ibrahim I. El-Sharkawy, Kutub Uddin, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Stefan K. Henninger, Characterization of adsorbent/refrigerant pairs for developing high performance adsorption cooling systems, Proceedings of the 7th Asian Conference on Refrigeration and Air Conditioning, 258, 2014.05. |
| 136. | I Gusti Agung Bagus Wirajati, Yuki Ueda, Atsushi Akisawa, Takahiko Miyazaki, The Performance of Three Bed Re-heat Combined Adsorption Chiller, Proceedings of the International Sorption Heat Pump Conference 2014, #7, 2014.04. |
| 137. | Takahiko Miyazaki, Ibrahim I. El-Sharkawy, Bidyut Baran Saha, Shigeru Koyama, Performance Prediction of Adsorption Heat Pump Systems Using Activated Carbon and R 32 Pair, Proceedings of the International Sorption Heat Pump Conference 2014, #92, 2014.04. |
| 138. | Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama, Bidyut Baran Saha, Utilization of Desiccant Air-Conditioning System for Improvement in Greenhouse Productivity: A Neglected Area of Research in Pakistan, International Journal of Environment, 4, 1, 1-10, 2014.03. |
| 139. | Marlinda, 上田祐樹, 秋澤淳, 宮崎隆彦, シリカゲル/FAM-Z01を用いた凝縮熱による二重効用吸着冷凍サイクルの性能解析, 日本冷凍空調学会論文集, 10.11322/tjsrae.31.1, 31, 1, 1-9, 2014.03. |
| 140. | Kutub Uddin, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Thermodynamic Analysis of Adsorption Cooling Cycle using Ethanol-Surface treated Maxsorb III Pairs, Evergreen - Joint Journal of Novel Carbon Resource Sciences & Green Asia Strategy, 1, 1, 25-31, 2014.03. |
| 141. | A.F.M.Mizanur Rahman, Y.Ueda, A.Akisawa, T.Miyazaki, B.B.Saha, Design and performance of Four-Stage Adsorption System, International Journal of Research in Engineeringand Science (IJRES), 2, 1, 1-10, 2014.01. |
| 142. | Kutub Uddin, Takahiko Miyazaki, Shigeru Koyama, Bidyut Baran Saha, Performance investigation of adsorption – compression hybrid refrigeration systems, International Journal of Air-Conditioning and Refrigeration, 21, 4, 1350024, 2013.11. |
| 143. | Kutub Uddin, Ibrahim I. El-Sharkawy, Takahiko Miyazaki, Bidyut Baran Saha, Shigeru Koyama, Hyun Sig Kil, Jin Miyawaki, Seongho YOON, Adsorption of ethanol onto carbon based adsorbents, Proceedings of the 11th Japan-China-Korea Joint Symposium on Cabon Saves the Earth, 2013.11. |
| 144. | Bidyut Baran Saha, Takahiko Miyazaki, Shigeru Koyama, Adsorption cooling cum desalination cycles, Proceedings of the 11th Japan-China-Korea Joint Symposium on Cabon Saves the Earth, 2013.11. |
| 145. | Takahiko Miyazaki, Shigeru Koyama, Bidyut Baran Saha, Analytical model of a combined adsorption cooling and mechanical vapor compression refrigeration system, Proceedings of the 6th International Meeting on Advanced Thermofluids, 2013.11. |
| 146. | Abul Fazal Mohammad Mizanur Rahman, Takahiko Miyazaki, Yuki Ueda, Bidyut Baran Saha, Atsushi Akisawa, Performance Comparison of Three-Bed Adsorption Cooling System With Optimal Cycle Time Setting, HEAT TRANSFER ENGINEERING, 10.1080/01457632.2012.753571, 34, 11-12, 938-947, 2013.09, 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.. |
| 147. | Ahamed A. Askalany, Bidyut Baran Saha, Kutub Uddin, Takahiko Miyazaki, Shigeru Koyama, Kandadai Srinivasan, Ibrahim M. Ismail, Adsorption isotherms and heat of adsorption of difluoromethane on activated carbons, Journal of Chemical & Engineering Data, 58, 2828-2834, 2013.09. |
| 148. | I Gusti Agung Bagus Wirajati, Yuki Ueda, Atsushi Akisawa, Takahiko Miyazaki, Cycle optimization on re-heat adsorption cycle applying fixed chilled water outlet temperature, The Proceedings of the IMPRES2013, 59-66, 2013.09. |
| 149. | Ahmed A. Askalany, Bidyut Baran Saha, Takahiko Miyazaki, Shigeru Koyama, Ibrahim M. Ismail, Modified linear driving force model for accurate approximation of adsorption kinetics experimental data, The Proceedings of the IMPRES2013, 351-355, 2013.09. |
| 150. | Kutub Uddin, Takahiko Miyazaki, Shigeru Koyama, Bidyut Baran Saha, Hyun Siq Kil, Jin Miyawaki, Seongho YOON, Adsorption kinetics of ethanol onto functional activated carbons with controlled oxygen content, The Proceedings of the IMPRES2013, 356-361, 2013.09. |
| 151. | Seung Taek Oh, KEISHI KARIYA, Yoshinori Hamamoto, Bidyut Baran Saha, Hideo Mori, Takahiko Miyazaki, Shigeru Koyama, Adsorption of water vapor onto silica gel using innovative compact fin and tube heat exchanger, The Proceedings of the IMPRES2013, 362-367, 2013.09. |
| 152. | Ibrahim I. El-Sharkawy, Hossam Abdelmeguid, Bidyut Baran Saha, Shigeru Koyama, Takahiko Miyazaki, Performance investigation of a solar-powered adsorption cooling system: a case study for Egypt, The Proceedings of the IMPRES2013, 390-395, 2013.09. |
| 153. | Takahiko Miyazaki, Ibrahim I. El-Sharkawy, Bidyut Baran Saha, Shigeru Koyama, Study on adsorption cooling system -Fundamental to system evaluation-, Proceedings of the International Conference on Green Energy and Technology, 153, 2013.08. |
| 154. | Muhammad Sultan, Takahiko Miyazaki, Shigeru Koyama, Bidyut Baran Saha, Consideration of solid desiccant dehumidification and air conditioning system for greenhouses of Pakistan: A feasibility study, Proceedings of the International Conference on Green Energy and Technology, 185-190, 2013.08. |
| 155. | Abul Fazal Mohammad Mizanur Rahman, Yuki Ueda, Atsushi Akisawa, Takahiko Miyazaki, Bidyut Baran Saha, Design and Performance of an Innovative Four-Bed, Three-Stage Adsorption Cycle, ENERGIES, 10.3390/en6031365, 6, 3, 1365-1384, 2013.03, 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.. |
| 156. | Naoya Makimoto, Miyazaki Takahiko, Koyama Shigeru, Cyclic performance of adsorption chiller using a compact adsorption heat exchanger, 14th Cross Straits Symposium on Energy and Environmental Science and Technology (14th CSS-EEST), 2013.02. |
| 157. | Kutub Uddin, Miyazaki Takahiko, Koyama Shigeru, Saha Baran Bidyut, Adsorption isotherms of R134a and R32 onto activated carbons, 14th Cross Straits Symposium on Energy and Environmental Science and Technology (14th CSS-EEST), 2013.02. |
| 158. | Kutub Uddin, Miyazaki Takahiko, Koyama Shigeru, Saha Baran Bidyut, Thermodynamic analysis of HFCs-ethnol sub-cooler type hybrid refrigeration system, 14th Cross Straits Symposium on Energy and Environmental Science and Technology (14th CSS-EEST), 2013.02. |
| 159. | Pornpipat Yoosa, Miyazaki Takahiko, Koyama Shigeru, Performance evaluation of desiccant dehumidification and evaporative cooling, 14th Cross Straits Symposium on Energy and Environmental Science and Technology (14th CSS-EEST), 2013.02. |
| 160. | Takuya Oda, Masakazu Ito, Norihiro Kawasaki, Takahiko Miyazaki, Takao Kashiwagi, Potential estimation of hourly blank storage space and charge loads of EVs using road traffic census and vehicles status, ELECTRICAL ENGINEERING IN JAPAN, 10.1002/eej.22352, 182, 3, 30-38, 2013.02, 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. |
| 161. | Abul Fazal Mohammad Mizanur RAHMAN, Yuki UEDA, Atsushi AKISAWA, Takahiko MIYAZAKI, Bidyut Baran SAHA, Innovative Design and Performance of Three-Bed Two-Stage Adsorption Cycle under Optimized Cycle Time, Journal of Environment and Engineering, 10.1299/jee.7.92, 7, 1, 92-108, 2012.12, 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.. |
| 162. | 伊藤雅一, 小田拓也, 宮崎隆彦, 川崎憲広, 田口晋也, 杉原弘恭, 秋澤淳, 黒川浩助, 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, エネルギー・資源, 33, 6, 1-8, 2012.11. |
| 163. | Saha Baran Bidyut, Miyazaki Takahiko, Koyama Shigeru, Study on adsorption cooling cycles based on activated carbon and low GWP refrigerant pairs, 10th China-Japan-Korea Joint Symposium on Carbon Materials to Save the Earch, 2012.11. |
| 164. | Miyazaki Takahiko, Koyama Shigeru, Kutub Uddin, Dynamic simulation on a mechanical/thermal compression hybrid air-conditionning cycle, The 6th Asian conference on Refigeration and Air Conditioning (ACRA2012), 2012.08. |
| 165. | Takahiko Miyazaki, Shigeru Koyama, Low pressure refrigeration cycle using CO2 refrigerant by adsorption phenomena, Proceedings of the Eighth KSME-JSME Thermal and Fluids Engineering Conference, GST01-003, 2012.03. |
| 166. | Naoya Makimoto, Takahiko Miyazaki, Shigeru Koyama, The effect of heating water temperature on the performance of an adsorption cooling system using activated carbon power/ethanol pair, Proceedings of the 13th Cross Straits Symposium on Materials, Energy and Environmental Engineering, ETP-2, 2011.11. |
| 167. | Takahiko Miyazaki, Atsushi Akisawa, Isao Nikai, The cooling performance of a building integrated evaporative cooling system driven by solar energy, ENERGY AND BUILDINGS, 10.1016/j.enbuild.2011.05.004, 43, 9, 2211-2218, 2011.09, 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.. |
| 168. | 宮崎隆彦, 秋澤淳, 二階勲, 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, 日本冷凍空調学会論文集, 10.11322/tjsrae.28.269, 28, 3, 269-277, 2011.09. |
| 169. | Takahiko Miyazaki, Yuya Tani, Yuki Ueda, Atsushi Akisawa, The experimental investigation of the dual evaporator type adsorption chiller, Proceedings of the 10th IEA Heat Pump Conference 2011, ID 3.38, 2011.06. |
| 170. | 石田康, 坂内正明, 宮崎 隆彦, 中沢真一, 横山隆一, バイオマス利用エネルギー供給システムの経済性・環境性評価—産業系事業所における木質バイオマスコージェネレーション導入の効果分析—, 日本エネルギー学会誌, 90, 6, 547-553, 2011.06. |
| 171. | 小田拓也, 伊藤雅一, 川崎憲広, 宮崎隆彦, 柏木孝夫, 交通センサス観測結果等を用いた乗用車のEV充電負荷曲線 と充電ポテンシャルの推定, 電気学会論文誌B, 131, 12, 920-926, 2011.05. |
| 172. | Takahiko Miyazaki, Isao Nikai, Atsushi Akisawa, Simulation analysis of an open-cycle adsorption air conditioning system − Numeral modeling of a fixed bed dehumidification unit and the maisotsenko cycle cooling unit, International Journal of Energy for a Clean Environment, 12, 2-4, 341-354, 2011.04. |
| 173. | 小野晴明, 荒木圭司, 小田拓也, 宮崎隆彦, 上田裕樹, 秋澤 淳, 石油残渣IGCCの適用が電源構成と石油精製工程に与える影響, 日本エネルギ-学会誌, 90, 3, 235-246, 2011.03. |
| 174. | Marlinda, Aep Saepul Uyun, Takahiko Miyazaki, Yuki Ueda, Atsushi Akisawa, Performance Analysis of a Double-effect Adsorption Refrigeration Cycle with a Silica Gel/Water Working Pair, ENERGIES, 10.3390/en3111704, 3, 11, 1704-1720, 2010.11, 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.. |
| 175. | Atsushi Akisawa, Takahiko Miyazaki, Takao Kashiwagi, Theoretical analysis of the optimal configuration of co-generation systems and competitiveness of heating/cooling technologies, ENERGY, 10.1016/j.energy.2010.06.015, 35, 10, 4071-4078, 2010.10, 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.. |
| 176. | 小田拓也, 秋澤 淳, 宮崎隆彦, 柏木孝夫, PPSによるコージェネレーションの余剰電力融通 —経済的最適化が一次エネルギー消費に与える影響—, 電気学会論文誌B, 130, 8, 719-726, 2010.08. |
| 177. | T. Nualboonrueng, T. Miyazaki, Y. Ueda, A. Akisawa, The performance of PVT collector in Japan, Renewable Energy 2010, O-Th-1-3, 2010.07. |
| 178. | H. Sugihara, J. Yamashita, Y. Ikoma, A. Akisawa, T. Miyazaki, Y. Ueda, T. Kashiwagi, Estimation of GY photovoltaic energy generated by rooftop solar panel systems in Japan using GIS data, Renewable Energy 2010, O-Pv-4-2, 2010.07. |
| 179. | T. Miyazaki, A. Akisawa1, I. Nikai, Study on the Maisotsenko cycle evaporative cooler driven by the solar chimney, Renewable Energy 2010, O-Th-2-4, 2010.07. |
| 180. | A. Akisawa, M. Ashida, T. Miyazaki, Y. Ueda, M. Horio, Low-cost oriented micro hydropower using motorboat propellers as the hydro turbines, Renewable Energy 2010, O-Sh-2-4, 2010.07. |
| 181. | A. Akisawa, T. Miyazaki, Y. Ueda, Solar thermal collecting performance with non-imaging fresnel lens to concentrate infrared irradiation, Renewable Energy 2010, P-Th-8, 2010.07. |
| 182. | A. Akisawa, K. Araki, T. Miyazaki, Y. Ueda, Utilization of wasted heat from refuse incineration with heat transportation by ammonia-water heat pump system, Renewable Energy 2010, P-He-16, 2010.07. |
| 183. | H. Tasai, T. Miyazaki, A. Akisawa, Characteristics of CIS photovoltaic module, Renewable Energy 2010, OP-14-1, 2010.07. |
| 184. | Atsushi Akisawa, Takahiko Miyazaki, Yuki Ueda, Kazumichi Araki, Toshitaka Takei, Application of ammonia-water absorption cycle to transfer cooling and heating at ambi- ent temperature, Proceedings of the 5th Asian Conference on Refrigeration and Air-conditioning, A1-023, 2010.06. |
| 185. | Takahiko Miyazaki, Masato Takaku, Yuki Ueda, Atsushi Akisawa, The cycle time optimization of a novel dual evaporator type three-bed adsorption chiller, Proceedings of the 5th Asian Conference on Refrigeration and Air-conditioning, A1-040, 2010.06. |
| 186. | Masakazu Sato, Takahiko Miyazaki, Yuki Ueda, Atsushi Akisawa, Improvement of adsorption heat exchangers by the enhancement of contact points between adsorbent and surface, Proceedings of the 5th Asian Conference on Refrigeration and Air-conditioning, A6-043, 2010.06. |
| 187. | 小田拓也, 宮崎隆彦, 植田 譲, 伊藤雅一, 川崎憲広, 柏木孝夫, 既築建物等に対する空調用電力消費量の推定手法 —大学建物における検証—, 日本冷凍空調学会論文集, 27, 2, 95-102, 2010.06. |
| 188. | Takahiko Miyazaki, Atsushi Akisawa, Bidyut Baran Saha, The performance analysis of a novel dual evaporator type three-bed adsorption chiller, International Journal of Refrigeration, 10.1016/j.ijrefrig.2009.10.005, 33, 2, 276–285, 2010.03. |
| 189. | マルリンダ, 宮崎隆彦, 上田祐樹, 秋澤 淳, シリカゲル二重効用吸着冷凍サイクルの静的解析, 日本冷凍空調学会論文集, 27, 1, 57–65, 2010.03. |
| 190. | Marlinda, Aep Saepul Uyun, Takahiko Miyazaki, Yuki Ueda, Atsushi Akisawa, Numerical analysis of double effect adsorption refrigeration cycle using silica-gel/water working pair, 2010 International Symposium on Next- generation Air Conditioning and Refrigeration Technology, P10 1-8, 2010.02. |
| 191. | Takahiko Miyazaki, Yusaku Motohashi, Yuki Ueda, Atsushi Akisawa, Shinji Shindoh, Masazumi Godo, Takeshi Takatsuka, Study on energy saving air-conditioning system using compact desiccant ventilation units, Part 28: The optimization of the operating conditions of direct heating regeneration type desiccant unit, 2010 International Symposium on Next- generation Air Conditioning and Refrigeration Technology, GS17 1-7, 2010.02. |
| 192. | 宮崎隆彦,秋澤 淳,進藤伸二,神戸正純,高塚 威,濱本芳徳,森 英夫, 固定床型デシカント換気空調機の開発 第 1 報:各種吸着材を用いたデシカントユニットの性能評価, 日本冷凍空調学会論文集, 26, 4, 521-532, 2009.12. |
| 193. | 宮崎隆彦,秋澤 淳,上田祐樹,進藤伸二,神戸正純,高塚 威, 固定床型デシカント換気空調機の開発 第 2 報:蓄熱ユニットを備えたデシカント換気空調システムの吸着材再生方 式に関する検討, 日本冷凍空調学会論文集, 26, 4, 533-542, 2009.12. |
| 194. | A.S. Uyun, A. Akisawa, T. Miyazaki, Y. Ueda, T. Kashiwagi,, Numerical analysis of an advanced three-bed mass recovery adsorption refrigeration cycle, Applied Thermal Engineering, 10.1016/j.applthermaleng.2009.02.008, 29, 14-15, 2876–2884, 2009.10. |
| 195. | Aep Saepul Uyun, Takahiko Miyazaki, Yuki Ueda, Atsushi Akisawa, High performance cascading adsorption refrigeration cycle with internal heat recovery driven by a low grade heat source temperature, Energies, 10.3390/en20401170, 2, 4, 1170–1191, 2009.10. |
| 196. | Takahiko Miyazaki, Atsushi Akisawa, The influence of the heat exchanger parameters on the optimum cycle time of adsorption chillers, Applied Thermal Engineering, 10.1016/j.applthermaleng.2009.01.005, 29, 13, 2708–2717, 2009.09. |
| 197. | T. Miyazaki, A. Akisawa, B.B. Saha, I.I. El-Sharkawy, A. Chakraborty, A new cycle time allocation for enhancing the performance of two-bed adsorption chillers, International Journal of Refrigeration, 10.1016/j.ijrefrig.2008.12.002, 32, 5, 846–853, 2009.08. |
| 198. | 小田拓也,宮崎隆彦,秋澤 淳,柏木孝夫, PPSによるコージェネレーションの余剰電力融通 —電力取引のモデル化と利益配分の分析 —, 電気学会論文集 B, 129, 8, 1009-1017, 2009.08. |
| 199. | Aep Saepul Uyun, Takahiko Miyazaki, Yuki Ueda, Atsushi Akisawa, Experimental investigation of a three-bed adsorption refrigeration chiller employing an advanced mass recovery cycle, Energies, 10.3390/en20300531, 2, 3, 531–544, 2009.07. |
| 200. | 小田拓也,宮崎隆彦,伊藤雅一,柏木孝夫, 再生可能エネルギーと需要の双方の変動を考慮した電力貯蔵容量の基礎的解析, 電気学会論文集 B, 129, 5, 682–688, 2009.05. |
| 201. | Yasushi Ishida, Masaaki Bannai, Takahiko Miyazaki, Yasushi Harada, Ryuichi Yokoyama, Atsushi Akisawa, The optimal operation criteria for a gas turbine co- generation system, Energies, 10.3390/en20200202, 2, 2, 202–225, 2009.04. |
| 202. | 秋澤 淳,佐藤大幸,宮崎隆彦,柏木孝夫, 太陽熱温水器の屋根方位に対する導入確率と省エネルギー効果の期待値, 太陽エネルギー, 34, 6, 59–65, 2008.11. |
| 203. | 秋澤 淳,佐藤大幸,宮崎隆彦,柏木孝夫, 太陽熱温水器に対するユーザ意識のアンケート調査および選好特性の推定, 太陽エネルギー, 34, 6, 67–72, 2008.11. |
| 204. | A. Akisawa, S. Matsuo, T. Miyazaki, Y. Ueda, T. Kashiwagi, Application of solution transportation absorption heat pump to transfer cooling and heating with single working fluid, International Sorption Heat Pump Conference 2008, AB-105, 2008.09. |
| 205. | T. Miyazaki, Y. Higashida, I. Nikai, A. Akisawa, T. Kashiwagi, Performance improvement of desiccant air conditioning systems by the recirculation of product air, International Sorption Heat Pump Conference 2008, AB-027, 2008.09. |
| 206. | T. Miyazaki, A. Akisawa, T. Oda, T. Kashiwagi, Energy saving potential of adsorption chillers in office buildings by cycle time control at part load conditions, International Sorption Heat Pump Conference 2008, AB-028, 2008.09. |
| 207. | S. S. Elsayed, T. Miyazaki, Y. Hamamoto, A. Akisawa, T. Kashiwagi, Performance analysis of air cycle refrigerator integrated desiccant system for cooling and dehumidifying warehouse, International Journal of Refrigeration, 10.1016/j.ijrefrig.2007.07.002, 31, 2, 189–196, 2008.03. |
| 208. | 宮崎隆彦,秋澤 淳,柏木孝夫,赤平 亮, 大域的最適化手法の適用による吸着冷凍機の性能向上 — Particle Swarm Optimization によるサイクルタイムの最適化 —, 日本冷凍空調学会論文集, 25, 1, 9–19, 2008.03. |
| 209. | Masaaki Bannai, Yasushi Tomita, Yasushi Ishida, Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, Risk hedging against the fuel price fluctuation in energy service business, Energy, 10.1016/j.energy.2007.05.003, 32, 11, 2051–2060, 2007.11. |
| 210. | Aep Saepul Uyun, Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, Performance comparison of double-effect adsorption refrigeration cycles, Proceedings of the 8th Asian Thermophysical Properties Conference, 103, 2007.08. |
| 211. | Takahiko Miyazaki, Aep Saepul Uyun, Atsushi Akisawa, Takao Kashiwagi, Comparison of the optimum performances of adsorption heat pump cycles with various adsorbent- adsorbate pairs, Proceedings of the 8th Asian Thermophysical Properties Conference, 085, 2007.08. |
| 212. | I Gusti Agung Bagus Wirajati, Aep Saepul Uyun, K.C.A. Alam, Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, Experimental study on adsorption chiller with reheat two stage cycle, Proceedings of the 8th Asian Thermophysical Properties Conference, 015, 2007.08. |
| 213. | Md. Zafar Iqbal Khan, Bidyut Baran Saha, K.C. Amanul Alam, 宮崎隆彦,秋澤 淳,柏 木孝夫, 蒸気再生過程を組み込んだマルチベッド型吸着冷凍サイクルの性能向上, 日本冷凍 空調学会論文集, 23, 4, 399–408, 2006.12. |
| 214. | 宮崎隆彦,秋澤 淳,菅原大誉,柏木孝夫,坂内正明, 事務所ビルディングに対する省エネルギー方策の評価, 空気調和・衛生工学会論文集, 117, 21–28, 2006.12. |
| 215. | Atsuhiro Kawamura, Atsushi Akisawa, Takao Kashiwagi, Takahiko Miyazaki, Possibility of applying biomass energy to Japanese greenhouses for crop production, Renewable Energy 2006 Proceedings, 1103–1106, 2006.10. |
| 216. | Takahiko Miyazaki, Hiroyoshi Tasai, Atsushi Akisawa, Takao Kashiwagi, Development of a novel concentration photovoltaic generator for buildings with double facades: Design of a nonimaging Fresnel lens solar concentrator for vertical use, Renewable Energy 2006 Proceedings, 282–285, 2006.10. |
| 217. | Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, The effects of solar chimneys on thermal load mitigation of office buildings under the Japanese climate, Renewable Energy, 10.1016/j.renene.2005.05.003, 31, 7, 987–1010, 2006.06. |
| 218. | 宮崎隆彦,秋澤 淳,柏木孝夫, Particle Swarm Optimization による民生ビル用コージェネレーションシステムの最適化, 日本冷凍空調学会論文集, 23, 2, 145–156, 2006.06. |
| 219. | Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, Application of the particle swarm optimization to the design of heating and cooling plants of buildings, Proceedings of the 3rd Asian Conference on Refrigeration and Air-conditioning, I, 209–212, 2006.05. |
| 220. | Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, Energy savings of office buildings by the use of semi-transparent solar cells for windows, Renewable Energy, 10.1016/j.renene.2004.05.010, 30, 3, 281–304, 2005.03. |
| 221. | 宮崎隆彦,秋澤 淳,柏木孝夫, オフィスビルにおける省エネルギーを目的とした昼光利用と高性能窓システムの経済性評価, 太陽エネルギー, 31, 2, 51–56, 2005.03. |
| 222. | Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, Guohui Gan, A computational fluid dynamics analysis of solar chimneys integrated with photovoltaics, World Renewable Energy Congress VIII,, 2004.09. |
| 223. | Takahiko Miyazaki, Ralf Leutz, Atsushi Akisawa, Takao Kashiwagi, Energy self-sufficient urban buildings: Evaluation of buildings integrated photovoltaics, World Renewable Energy Congress VII, 2002.07. |
| 224. | 宮崎隆彦,秋澤 淳,柏木孝夫, LNG 冷熱を利用した三段階動力回収システム —エクセルギー効率を最大化するサイクル運転条件—, 日本冷凍空調学会論文集, 18, 2, 173–183, 2001.06. |
| 225. | Takahiko Miyazaki, Yong Tae Kang, Atsushi Akisawa, Takao Kashiwagi, A combined power cycle using refuse incinerator and LNG cold energy, Energy, 10.1016/S0360-5442(00)00002-5, 25, 7, 639–655, 2000.07. |
| 226. | Ralf Leutz, Bidyut B. Saha, Takahiko Miyazaki, Atsushi Akisawa, Takao Kashiwagi, Hiroshi Okano, Ryuji Kuramitsu, Desiccant dehumidification for solar driven absorption air conditioning, World Renewable Energy Congress V, 2122–2125, 1998.09. |
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九大関連コンテンツ
QIR 九州大学学術情報リポジトリ システム情報科学研究院
総合理工学研究院
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