| 1. |
Evaluation of the energy-saving measure against a business-use building. |
| 2. |
Improvement of Building Form for Energy Savings and Cost Reduction. |
| 3. |
Uddin Kutub, El-Sharkawy Ibrahim I., Miyazaki Takahiko, Saha Baran Bidyut, Koyama Shigeru, Thermodynamic Analysis of Adsorption Cooling Cycle using Ethanol-Surface treated Maxsorb Ⅲ Pairs, Evergreen, Vol.1, No.1, pp.25-31, 2014.03, We have devised a method that employs surface- and self-capacitive sensing principles for touch detection with a single-layered capacitive touch panel. In this method, a single electrode layer consisting of a stripe-shaped one-dimensional electrode array was used to enable multi-touch detection, and a capacitive sensing circuit that uses a trans-impedance amplifier was selected to simplify the circuit structure of the touch panel. The results indicate that the number of the panel fabrication processes and the amount of the touch electrode material required can be reduced by half by using the proposed method.. |
| 4. |
T Miyazaki, A Akisawa, T 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, Vol.30, No.3, pp.281-304, 2005.03, The study investigated a PV window that consists of a double glazed window with semi-transparent solar cells. The window provides natural light transmission as well as electricity production. The effect of the PV window on energy consumption of office buildings was analyzed in terms of heating and cooling loads, daylighting, and electricity production. The purposes of the study were to find the optimum solar cell transmittance and window to wall ratio (WWR), and to estimate energy savings of the building. A standard floor of an office building was modeled to run computer simulation, and annual energy simulation was performed with EnergyPlus. The results showed that the solar cell transmittance of 40% and WWR of 50% achieved the minimum electricity consumption in the building when artificial lighting was controlled with daylighting. The optimum solar cell transmittance for PV windows in different orientation was also presented. By using the optimum PV window, the electricity consumption was reduced by 55% compared to the single glazed window with WWR of 30% and no lighting control. (C) 2004 Elsevier Ltd. All rights reserved.. |
| 5. |
T Miyazaki, A Akisawa, T 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, Vol.31, No.7, pp.987-1010, 2006.06, The study investigated the performance of a solar chimney, which is integrated into a south facade of a one-story building, as well as the effect on the heating and cooling loads of the building by using a CFD simulation and an analytical model. A C programming code was developed for the calculation of the heating and cooling loads by the heat balance method. The analytical equations of a solar chimney were incorporated into the heat balance calculation. The results showed that the fan shaft power requirement was reduced by about 50% in annual total due to the natural ventilation. It was also found that the solar chimney was beneficial to reduce the heating load by about 20% during the heating season. The annual thermal load mitigation was estimated as 12% by taking the increase of the cooling load into account. (c) 2005 Elsevier Ltd. All rights reserved.. |
| 6. |
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, Vol.32, No.11, pp.2051-2060, 2007.11, Energy service business, or energy service company (ESCO), is expanding among industrial users as a means of energy saving. The ESCO business normally tends to become a long-term operation. During the operation, fluctuations of fuel and electricity costs significantly impact on the stability of the profit from ESCO business. Therefore, it is essential to reduce the risk of fuel and electricity cost fluctuations. Generally, a transaction called "financial derivative" is used as a measure of hedging against the fuel price fluctuation. In the case of ESCO business, it is necessary to manage the risk of both electricity and fuel price fluctuations because the variation in electricity price strongly affects the profit from ESCO as that in fuel price does.
In this paper, the stabilization of the ESCO profit using financial derivatives was discussed by quantitative analyses of the actual data from existing plants. Case studies revealed that the appropriate volume of the fuel derivative implementation was less than a half of the fuel consumption at the ESCO facilities, and it ranged from 5% to 50%. (C) 2007 Elsevier Ltd. All rights reserved.. |
| 7. |
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-REVUE INTERNATIONALE DU FROID, 10.1016/j.ijrefrig.2007.07.002, Vol.31, No.2, pp.189-196, 2008.03, In this paper, the performance of air cycle refrigerator integrated desiccant system used to cool and dehumidify warehouse is analyzed theoretically. Simulation analysis is carried out to calculate the system coefficient of performance, cooling effects and the humidity change under different values of pressure ratio, storage zone temperature inside dock and outdoor air conditions. Also, the effect of the air cycle and the rotor parameters on the system performance is evaluated. From the simulation result it is found that, the desiccant system has the ability to supply air to the dock area at very low humidity. The system coefficient of performance increases due to the exhaust heat recovery on the desiccant system, and this enhancement can be more than 100%. The coefficient of performance of the proposed system is greater than that of a conventional system under the same operating conditions. (C) 2007 Elsevier Ltd and IIR. All rights reserved.. |
| 8. |
Takahiko Miyazaki, Atsushi Akisawa, The influence of heat exchanger parameters on the optimum cycle time of adsorption chillers, APPLIED THERMAL ENGINEERING, 10.1016/j.applthermaleng.2009.01.005, Vol.29, No.13, pp.2708-2717, 2009.09, The research investigated the influences of heat exchanger parameters, such as heat capacity and NTU, on the optimum performance of a single-stage adsorption chiller. Silica gel-water pair was chosen as the adsorbent-adsorbate combination so that low temperature heat source under than 100 degrees C could be utilized as the driving force.
The mathematical model of the adsorption chiller using dimensionless parameters was developed and a global optimization method called the particle swarm optimization was applied in the simulation to obtain the optimum cycle time. The results showed that the smaller heat capacity heat exchanger improved both the maximum specific cooling capacity (SCC) and the COP. While, the larger NTU of the adsorbent bed resulted in the decrease of the COP due to the short cycle time although the maximum SCC was enhanced. (c) 2009 Elsevier Ltd. All rights reserved.. |
| 9. |
Yasushi Ishida, Masaaki Bannai, Takahiko Miyazaki, Yasushi Harada, Ryuichi Yokoyama, Atsushi Akisawa, The Optimal Operation Criteria for a Gas Turbine Cogeneration System, ENERGIES, 10.3390/en20200202, Vol.2, No.2, pp.202-225, 2009.06, The study demonstrated the optimal operation criteria of a gas turbine cogeneration system based on the analytical solution of a linear programming model. The optimal operation criteria gave the combination of equipment to supply electricity and steam with the minimum energy cost using the energy prices and the performance of equipment. By the comparison with a detailed optimization result of an existing cogeneration plant, it was shown that the optimal operation criteria successfully provided a direction for the system operation under the condition where the electric power output of the gas turbine was less than the capacity.. |
| 10. |
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, Vol.29, No.14-15, pp.2876-2884, 2009.10, Numerical analysis of an adsorption cycle employing advanced three-bed mass recovery cycle with and without heat recovery is introduced in this paper. The cycle consists of three silica gel adsorbent beds with different heat utilization functions. The beds can be divided into two cycles with different desorption mechanisms. The working principle of the cycle is introduced, and performances of three-bed, single stage, and mass recovery adsorption cycles are compared in terms of coefficient of performance (COP) and specific cooling power (SCP). The paper also presents the effect of adsorber mass distribution and desorption time on performance. The results show that by applying heat recovery to the cycle, better COP values will be produced compared to that without heat recovery. The results also show that there is an optimum point of adsorber mass distribution and desorption time that produces optimum performance. Furthermore, the paper also compares the performances of the proposed cycle, a single-stage cycle, and a mass recovery cycle. (C) 2009 Elsevier Ltd. All rights reserved.. |
| 11. |
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, Vol.2, No.4, pp.1170-1191, 2009.12, This paper presents the performance of an advanced cascading adsorption cycle that utilizes a driven heat source temperature between 90-130 degrees C. The cycle consists of four beds that contain silica gel as an adsorber fill. Two of the beds work in a single stage cycle that is driven by an external heat source, while the other two beds work in a mass recovery cycle that is driven by waste heat of sensible and adsorption heat of the high temperature cycle. The performances, in terms of the coefficient of performance (COP) and the specific cooling power (SCP), are compared with conventional cascading-without-mass-recovery and single-stage cycles. The paper also presents the effect of the adsorbent mass on performance. The results show that the proposed cycle with mass recovery produces as high of a COP as the COP that is produced by the conventional cascading cycle. However, it produces a lower SCP than that of the single-stage cycle.. |
| 12. |
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, Vol.2, No.3, pp.531-544, 2009.09, The performance of an advanced three-bed adsorption chiller with a mass recovery cycle has been experimentally investigated in the present study. The temperature and pressure of various components of the chiller were monitored to observe the dynamic behaviour of the chiller. The performances in terms of the coefficient of performance (COP) and specific cooling power (SCP) were compared with a conventional single stage. The results show that the proposed cycle produces COP and SCP values superior to those of the conventional single stage cycle for heat source temperature below 75 degrees C.. |
| 13. |
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, Vol.2, No.3, pp.531-544, 2009.09, The performance of an advanced three-bed adsorption chiller with a mass recovery cycle has been experimentally investigated in the present study. The temperature and pressure of various components of the chiller were monitored to observe the dynamic behaviour of the chiller. The performances in terms of the coefficient of performance (COP) and specific cooling power (SCP) were compared with a conventional single stage. The results show that the proposed cycle produces COP and SCP values superior to those of the conventional single stage cycle for heat source temperature below 75 degrees C.. |
| 14. |
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-REVUE INTERNATIONALE DU FROID, 10.1016/j.ijrefrig.2008.12.002, Vol.32, No.5, pp.846-853, 2009.08, The present study proposed a new cycle time allocation in silica gel-water based adsorption chillers to enhance their performances. The new cycle time allocation not only improves the cooling capacity and coefficient of performance (COP), but also contributes in the reduction of delivered chilled water fluctuations. In a conventional adsorption chiller operation, the appropriate pre-heating/pre-cooling process enhances the cooling capacity, whereas the excess pre-heating/pre-cooling time abates the average cooling capacity. The proposed new cycle time allocation allows the continuous cooling effect over the cycle without sacrificing the effect of pre-heating/pre-cooling. Simulation results showed that the new cycle time was effective for both RD type silica gel-water and CaCl(2)-in-silica gel-water pairs, and the cooling capacity was increased as much as by 6%. (C) 2008 Elsevier Ltd and IIR.. |
| 15. |
Takahiko Miyazaki, Atsushi Akisawa, Bidyut Baran Saha, The performance analysis of a novel dual evaporator type three-bed adsorption chiller, INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID, 10.1016/j.ijrefrig.2009.10.005, Vol.33, No.2, pp.276-285, 2010.03, This paper deals with the performance evaluation of an innovative, waste heat driven dual evaporator type three-bed adsorption cycle for cooling application. The innovative adsorption chiller has two evaporators, three adsorbent beds, and a condenser, and the evaporators work at different pressure levels.
The effects of hot water inlet temperature, chilled water inlet and outlet temperatures, and cycle time on the specific cooling capacity (SCC) and coefficient of performance (COP) were predicted by simulation. For the same operating condition, the SCC and COP of the dual evaporator type three-bed adsorption chiller were found to be 1.5 and 1.7 times higher than those of the two-bed single-stage adsorption chiller, respectively. (C) 2009 Elsevier Ltd and IIR. All rights reserved.. |
| 16. |
The cycle time optimization of a novel dual evaporator type three-bed adsorption chiller
Copyright © 2010 by the Japan Society of Refrigeration and Air Conditioning Engineering (JSRAE). The novel, dual evaporator type three-bed adsorption chiller was proposed for the enhancement of the performance of adsorption chillers. The chiller is equipped with two evaporators, three adsorbent beds, and a condenser. The evaporators work at different pressure levels, which enhances the working range of the adsorbate concentration. It was predicted that the specific cooling capacity and the coefficient of performance of the dual evaporator type three-bed adsorption chiller enhanced by 50% and by 70%, respectively, compared with the conventional, two-bed single-stage adsorption chiller at the same operating conditions. The aim of the study was to further increase the specific cooling capacity of the dual evaporator type three-bed adsorption chiller by the optimization of the operating conditions. It is known that the cooling capacity of adsorption chillers can be maximized by the optimal cycle time. In the study, the particle swarm optimization was applied to the simulation of the dual evaporator type three-bed adsorption chiller and the optimal cycle time of the chiller was found. The results showed that the performance improvement by the optimization was significant in the case of driving heat source temperature under 75°C.. |
| 17. |
Multi-bed adsorption heat pump cycles and their optimal operation
© 2010 by Nova Science Publishers, Inc. All rights reserved. The chapter consists of two parts. The first part describes advanced adsorption heat pump cycles. The second part presents cycle simulations with optimization to maximize cooling effect. Multi-stage adsorption heat pump cycles are expected to utilize low temperature heat of 50-70 degC. Two-stage cycle and three-stage cycle have been investigated experimentally to clarify appropriate range of heat source temperature. Furthermore, new single stage cycles are proposed based on an idea of reheat scheme, where single stage cycle operates as quasi-two stage cycle. It can expand the temperature range for lower side. The other interesting idea is single stage cycle with three beds in contrast with two beds of conventional single stage cycle. The third bed runs twice as quickly as the other beds to adsorb more vapor from the evaporator. The process of mass recovery from desorption side to adsorption side has an important role in the cycles. Configuration, operation and performance of the cycles are described in the first part. In the second part, adsorption cycles have some control variables for the operation such as cycle time allocation for adsorption, desorption, precooling, preheating processes. It means that cycle has freedom to maximize the performance under given external conditions. It was, however, difficult to attain the optimum due to large freedom of the system. The authors succeeded to employ a nonlinear optimization technique named Particle Swarm Optimization to find optimal time allocation. The method, optimal settings of the parameters and optimal performance are discussed.. |
| 18. |
Improvement of adsorption heat exchangers by the enhancement of contact points between adsorbent and surface
Copyright © 2010 by the Japan Society of Refrigeration and Air Conditioning Engineering (JSRAE). In this study, we are aiming at the improvement of heat exchangers for the adsorption heat pump. To achieve it, it is important to reduce thermal contact resistance between adsorbent and heat transfer surface. The thermal contact resistance can be reduced by increasing the contact points between adsorbents and heat transfer surface. To increase the contact points, four patterns of heat transfer surface geometry were examined. They are flat surface, V-shaped surface, oblong surface, and arc shaped surface, which have one, two, three and maximum contact points, respectively. The flat surface is the one used by the conventional heat exchanger, and the arc shaped surface is the ideal one. The heat conduction in the adsorbent (silica gel) bed was predicted by mathematical simulation. The structure of adsorbent bed was the hexagonal closest packing. For the fundamental analysis, a two dimensional model was developed, and steady-state simulation was performed. The results showed that V-shaped surface could increase heat flux by 10 %. In addition, the reduction of the thermal contact resistance was more effective on the thinner adsorbent layer than that on the thicker one.. |
| 19. |
Application of ammonia-water absorption cycle to transfer cooling and heating at ambient temperature
Copyright © 2010 by the Japan Society of Refrigeration and Air Conditioning Engineering (JSRAE). Utilizing wasted heat is an important issue to reduce primary fuel consumption. Because wasted heat sources are not always located near heat demand, it is required to transport thermal energy efficiently. The authors proposed an application of absorption cycle to heat transportation. In contrast with conventional chilled water transportation, the proposed absorption system has the generator-condenser pair at the heat source side while the evaporator-absorber pair at the demand side, and transfers absorption solutions between them. The solution transportation can transfer thermal energy which is converted into the difference of solution concentration. In this study, the proposed system named STA is expanded to supply heating from the absorber as well, which enhances the COP and reduces primary fuel consumption. STA combined with refuse incineration power generation was investigated to utilize steam from the incineration to provide power, cooling and heating simultaneously. The primary fuel substitution is estimated to be 1.7 times as much as that of power generation only system.. |
| 20. |
Dynamic simulation on a mechanical/thermal compression hybrid air-conditioning cycle
In the study, we propose a hybrid air-conditioning cycle of mechanical vapour compression and thermal vapour compression. In the bottoming cycle, the refrigerant is compressed by a mechanical compressor from the evaporator to the medium pressure condenser. In the topping cycle, the other refrigerant is compressed by adsorption phenomena, where low temperature heat is used as a driving force, from the medium pressure condenser to the higher pressure condenser. R 1234ze is the refrigerant of the mechanical compression cycle, while CO2 is the refrigerant of the thermally compression cycle, where the activated carbon is the adorbent of CO2. Based on the measured adsorption kinetics of CO2 on the activated carbon, the system is modelled using MATLAB/SIMULINK. The dynamic characteristics of the system is investigated by simulation, and the reduction in mechanical power for the mechanical compressor is revealed.. |
| 21. |
Thermodynamic analysis of adsorption cooling cycle using ethanol-surface treated Maxsorb III pairs
© 2014, Novel Carbon Resource Sciences. All rights reserved. Adsorption isotherms of ethanol onto surface treated activated carbons, namely H 2 treated Maxsorb III and KOH-H 2 treated Maxsorb III have been investigated experimentally. The magnetic suspension adsorption measurement unit of type MSB-VG-S2 is used for measuring the equilibrium uptake over adsorption temperatures range from 30 to 70 ºC and evaporation temperatures between -6 and 65 ºC. The Dubinin-Radushkevich (D-R) and Dubinin-Astakhov (D-A) adsorption isotherm models are used to correlate the experimental data and to draw pressure-temperature-concentration (P-T-W) diagrams of the assorted pairs. Employing a time independent thermodynamic model, the coefficient of performance (COP) and specific cooling capacity (SCE) of the ideal adsorption cooling cycle has also been studied. Theoretical results show that the cycle performance using H 2 -Maxsorb III/ethanol pair is superior to that of KOH-H 2 -Maxsorb III/ethanol pair.. |
| 22. |
Performance simulation of adsorption refrigeration/heat pump with silica gel-water and activated carbon-ethanol combinations
The paper compared the performances of adsorption refrigeration/heat pump systems between the silica gel-water and the activated carbon-ethaonol as adsorbent-adsorbate combinations. The system performance was predicted in a wide range of heat source/sink by simulation. The adsorption isotherm and kinetics of the silica gel-water pair were taken from the literature, and those of the activated carbon-ethanol pair were measured by our group. The results revealed the suitable range for each combination for the application of space cooling, space heating, and hot water production.. |
| 23. |
Experimental study on carbon based adsorbents for greenhouse dehumidification
© 2014, Novel Carbon Resource Sciences. All rights reserved. Adsorption of water vapors onto silica-gel and two types of carbon based adsorbents (CBAs) has been experimentally investigated. Adsoption data has been analyzed for various adsorption models. The Guggenhein, Anderson. De-Boer (GAB) and Dubinin-Astakhov (D-A) models gave the good fit for silica-gel and CBAs respectively with an error of less than 5%. The greenhouse air-is proposed the water sorption application for CBAs. Results showed that the CBAs can dehumidify the greenhouse air by utilizing low regeneration temperature and 3-6 times less adsorbent mass as compared to silica-gel. The isosteric heat of adsorption of CBA & Iwater pair does not extremely effect on dehumidification performance.. |
| 24. |
Characterization of adsorbent/refrigerant pairs for developing high performance adsorption cooling systems
This paper presents an experimental investigation of adsorption isotherms and kinetics of promising adsorbent/refrigerant pairs towards the performance improvement of adsorption cooling systems. Adsorbents used in the present study are (i) parent Maxsorb III, (ii) KOH-H2 treated Maxsorb III, and (iii) a metal organic framework (MOF) material namely, MIL-101Cr. 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 whilst adsorption kinetics is presented by the Fickian diffusion model. Experimental results show that, among the assorted pairs, parent Maxsorb III/ethanol pair has the highest adsorption equilibrium uptake. However, the diffusional time constant of MIL-101Cr is found to be higher than that of other studied pairs.. |
| 25. |
A study on adsorption of water onto carbon based adsorbents
In the present study, an experimental analysis for adsorption of water onto carbon based adsorbent i.e. activated carbon powder (AC) has been presented. An experimental system has been employed to measure adsorption isotherms of AC and RD type silica-gel with water. Experimental data for AC have been correlated using an appropriate adsorption isotherm model. The isosteric heat of adsorption of the assorted AC/water pair has been extracted from the present experimental data. On the basis of experimental investigation the greenhouse desiccant air-conditioning (DAC) is proposed as an appropriate water-sorption application for AC. A psychometric comparison of AC with silica-gel for greenhouse DAC is given which highlights the importance of carbon-water pair in the adsorption science.. |
| 26. |
Overview of adsorption cooling system based on activated carbon - alcohol pair
© 2015, Novel Carbon Resource Sciences. All rights reserved. The depletion of ozone layers and climate problems have been calling for rapid developments in chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HFCs) free air conditioning and heat pump technologies. Using environmental benign refrigerants such as alcohol in adsorption air-conditioning systems will reduced the production of unwanted ozone depleting substances, whilst activated carbon as adsorbent can achieve higher adsorption capacity and rapid adsorption uptake rates. Additionally, it’s also environmental friendly and harmless. From this viewpoint, utilization of activated carbon adsorption system using natural alcohol as refrigerants has been in demand. The researchers put efforts to enhance the performance of adsorption systems by modification in adsorbent properties, optimizing the adsorbers’ heat exchanger design, and so on towards making this technology competitive with the available cooling system in the market. The objective of this paper is to review on the past efforts of various kinds of researches and methods used to validate the efficiency and suitability of activated carbon as the adsorbent material, with ethanol/methanol for cooling and refrigerant applications.. |
| 27. |
Thermodynamic analysis of adsorption cooling cycle using consolidated composite adsorbents - ethanol pairs
©2006-2016 Asian Research Publishing Network (ARPN). This study deals with the thermodynamic analysis of adsorption cooling cycle using consolidated composite adsorbents-ethanol pairs. The studied composites are named as composite A (50% Maxsorb III, 40% expanded graphite (EG), 10% binder) and composite C (70% Maxsorb III, 20% expanded graphite (EG), 10% binder). The Dubinin-Radushkevich (D-R) and Dubinin Astakhov (D-A) equation are used to draw pressure-temperature-concentration (P-T-W) diagrams of the assorted pairs. The specific cooling effect (SCE) and coefficient of performance (COP) of both pairs have been simulated for desorption temperatures ranging from 40 to 90 °C at different evaporator temperatures along with a heat sink at 30 °C by considering a time independent thermodynamic model. The maximum COPs of composite A-ethanol and composite C-ethanol based cooling systems are found to be 0.69 and 0.765, respectively.. |
| 28. |
Simulation analysis of heat recovery humidifier
The study investigated a highly effective humidifier employing the Maisotsenko-Cycle heat and mass recovery structure. The performance of the proposed humidifier is predicted by simulation and humidifying capacity was predicted.. |
| 29. |
Performance investigation of a finned tube adsorber employing activated carbon-ethanol pair
This study presents 2D-axisymmetric heat and mass transfer simulations of a finned tube adsorber employing activated carbon-ethanol as the adsorbent-refrigerant pair. The simulation is carried out with Ansys-Fluent v16.2 and the mathematical model consists of mass, momentum and energy conservation equations as well as confirmed adsorption isotherms and adsorption kinetics from measured experimental data. The simulated temperatures at different adsorbent thicknesses agreed fairly with those measured in an adsorption chiller setup in our laboratory. Moreover performance investigation is performed for heating, cooling and evaporation temperature of 80, 30 and 15 °C, respectively. The cooling capacity reached 245.9 W/kgAC whereas COP is found to be 0.42. The CFD simulation will allow design and performance optimization of the finned tube adsorber for adsorption chiller applications. It can be extended also to different absorber-heat exchanger designs and different adsorbent-refrigerant pairs.. |
| 30. |
Desiccant air-conditioning system for storage of fruits and vegetables: Pakistan preview
© 2015, Novel Carbon Resource Sciences. All rights reserved. In the present study the desiccant air-conditioning system has been investigated for the on-farm storage of fruits and vegetables in Pakistan. In this regard, ideal storage zone for the studied agricultural products is established in order to ascertain the system applicability. The dehumidification performance of the silica-gel based desiccant wheel has been analysed with low regeneration temperature (50°C. by using the model of Beccali et. al. Three environmental conditions (A: highly humid, B: moderately humid & C: less humid. are considered for the analysis of desiccant air-conditioning system. The latent and sensible loads of air-conditioning are achieved by the silica-gel desiccant wheel dehumidification and Maisotsenko cycle evaporative cooling respectively. The results of the study envisaged that desiccant wheel performs higher dehumidification in climatic condition ‘A’ due to higher ambient air relative humidity as compared to the other climatic conditions. However, higher heat energy is required for its regeneration in the climatic condition ‘A’. This study concluded that the desiccant air-conditioning system can be efficiently used for on-farm storage of fruits and vegetables in Pakistan. Also, the renewable energy sources of the country like solar energy and bio-gas can be potentially harvested for the regeneration of desiccant wheel. The study further proposes the use of hybrid desiccant air-conditioning system where standalone DAC system cannot achieve the sensible load.. |
| 31. |
Adsorption characteristics of consolidated adsorbents + ethanol pairs
In this study, adsorption characteristics of ethanol onto consolidated composite adsorbents have been investigated experimentally. The prepared consolidated composites are combinations of highly porous activated carbon powder namely Maxsorb III, expanded graphite (EG) and binder with judiciously selected mass ratios. Samples with different packing densities and different compositions have been prepared. Adsorption equilibrium uptakes of ethanol onto the prepared samples have been measured. Experiments have been conducted across assorted adsorption temperatures that are useful for the operation of adsorption chillers. The Dubinin-Astakhov (D-A) and the Dubinin-Radushkevich (D-R) equations have been used to fit the adsorption isotherm data. Thermal conductivities of the prepared composites have been measured using a microflash apparatus. Results showed that the thermal conductivities of prepared samples are significantly higher than those of activated carbon powders.. |
