In this paper, thermodynamic properties, such as yap or-liquid-equilibrium.vapor pressure, enthalpy and entropy of R22-DMA (Dimethyl acetamide), and the computation method are presented. With the thermodynamic-propert...In this paper, thermodynamic properties, such as yap or-liquid-equilibrium.vapor pressure, enthalpy and entropy of R22-DMA (Dimethyl acetamide), and the computation method are presented. With the thermodynamic-property database, a basic type of absorption compression heat pump (BSCHR) with recuperator and regenerator was simulated numerically and the performance of this heat pump under the typical air-cooling conditions was optimized. the results demonstrate that a batter coefficient of performance (COPg) can be achieved by optimizing the solution concentration and circulation rate.展开更多
In view of different compressor adding ways in the ammonia-water absorption/compression combined refrigeration AWA /CCR cycle combining the Schulz state equation of the ammonia-water solution the theoretical analysis ...In view of different compressor adding ways in the ammonia-water absorption/compression combined refrigeration AWA /CCR cycle combining the Schulz state equation of the ammonia-water solution the theoretical analysis and calculations on two combination ways by adding the compressor in the high-pressure area and in the low-pressure area are conducted respectively.The effects of several factors including the evaporation temperature Te heat-source temperature Th as well as the cooling water temperature Tw on the equivalent heat consumption in compression qCW heat consumption in absorption qG and the system coefficient of performance COP are analyzed under the two combination configurations.The results show that the effect of the equivalent heat consumption in compression on the COP is less than that of the heat consumption in absorption.Besides the compressor set in the high-pressure area uses more energy than that in the low-pressure area. Moreover the compressor in the low-pressure area is superior to that in the high-pressure area with respect to the COP. Under the given intermediate pressure there is an optimum heat-source temperature corresponding to the maximum COP of the AWA/CCR cycle.展开更多
The absorption-compression heat pump （ACHP） has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the AC...The absorption-compression heat pump （ACHP） has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the ACHP with NH3/H20 as working fluid were performed. Thermodynamic properties of each point and heat transfer rate of each component in the cycle under basic operation conditions were calculated from the first law analysis. Following the second law of thermodynamics, the entropy generation of each component and the total entropy generation of the system were obtained. The effect~ of the heating temperature, heat source temperature, and compression ratio on the coefficient of performance （COP） and the total entropy generation （ STot ） of the system were examined. The results show that the increase in COP corresponds to a decrease in STot, and vice versa; besides, for certain operating conditions, an optimum compression ratio in the NH~/H20 ACHP exists.展开更多
文摘In this paper, thermodynamic properties, such as yap or-liquid-equilibrium.vapor pressure, enthalpy and entropy of R22-DMA (Dimethyl acetamide), and the computation method are presented. With the thermodynamic-property database, a basic type of absorption compression heat pump (BSCHR) with recuperator and regenerator was simulated numerically and the performance of this heat pump under the typical air-cooling conditions was optimized. the results demonstrate that a batter coefficient of performance (COPg) can be achieved by optimizing the solution concentration and circulation rate.
基金The National Natural Science Foundation of China(No.51176029)
文摘In view of different compressor adding ways in the ammonia-water absorption/compression combined refrigeration AWA /CCR cycle combining the Schulz state equation of the ammonia-water solution the theoretical analysis and calculations on two combination ways by adding the compressor in the high-pressure area and in the low-pressure area are conducted respectively.The effects of several factors including the evaporation temperature Te heat-source temperature Th as well as the cooling water temperature Tw on the equivalent heat consumption in compression qCW heat consumption in absorption qG and the system coefficient of performance COP are analyzed under the two combination configurations.The results show that the effect of the equivalent heat consumption in compression on the COP is less than that of the heat consumption in absorption.Besides the compressor set in the high-pressure area uses more energy than that in the low-pressure area. Moreover the compressor in the low-pressure area is superior to that in the high-pressure area with respect to the COP. Under the given intermediate pressure there is an optimum heat-source temperature corresponding to the maximum COP of the AWA/CCR cycle.
基金National Key Technologies R&D Program of China(No. 2012BABZ︱2B01)National Natural Science Foundation of China(No. 51106161)Innovation Foundation of President of Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences(No. 0907r7)
文摘The absorption-compression heat pump （ACHP） has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the ACHP with NH3/H20 as working fluid were performed. Thermodynamic properties of each point and heat transfer rate of each component in the cycle under basic operation conditions were calculated from the first law analysis. Following the second law of thermodynamics, the entropy generation of each component and the total entropy generation of the system were obtained. The effect~ of the heating temperature, heat source temperature, and compression ratio on the coefficient of performance （COP） and the total entropy generation （ STot ） of the system were examined. The results show that the increase in COP corresponds to a decrease in STot, and vice versa; besides, for certain operating conditions, an optimum compression ratio in the NH~/H20 ACHP exists.
