TY - JOUR
T1 - Adsorption heat transformer cycle using multiple adsorbent + water pairs for waste heat upgrade
AU - Saren, Sagar
AU - Mitra, Sourav
AU - Miyazaki, Takahiko
AU - Ng, Kim Choon
AU - Thu, Kyaw
N1 - Funding Information:
Sagar Saren would like to express his gratitude to the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan and Japan International Cooperation Agency (JICA) under the Innovative Asia program for their support through scholarship, while the authors gratefully acknowledge the Cooling Initiative grant, REP/1/3988-01-01” and subaward OSR-Cooling-2018- 3988.3 from King Abdullah University of Science and Technology (KAUST).
Publisher Copyright:
© 2022, Akadémiai Kiadó, Budapest, Hungary.
PY - 2023/4
Y1 - 2023/4
N2 - 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.
AB - 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.
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U2 - 10.1007/s10973-022-11350-3
DO - 10.1007/s10973-022-11350-3
M3 - Article
AN - SCOPUS:85128962129
SN - 1388-6150
VL - 148
SP - 3059
EP - 3071
JO - Journal of Thermal Analysis and Calorimetry
JF - Journal of Thermal Analysis and Calorimetry
IS - 8
ER -