Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water whe...Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.展开更多
In this paper, the simulation approach and exergy analysis of multi-stage compression high tempera- ture heat pump （HTHP） systems with R1234ze（Z） working fluid are conducted. Both the single-stage and multi-stage ...In this paper, the simulation approach and exergy analysis of multi-stage compression high tempera- ture heat pump （HTHP） systems with R1234ze（Z） working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120℃ pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compres- sion system. The multi-stage compression system has better energy and exergy etticiencies with the increase of compression stage number. Compared with the single- stage compression system, the coefficient of performance （COP） improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. When the waste heat source temperature is 60℃, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respec- tively.展开更多
A new-type multiple-source heat pump cycle with two-stage compression was established on the basis of the problems of similarly existing heat pumps.The equivalent temperature levels of typical evaporators are applied ...A new-type multiple-source heat pump cycle with two-stage compression was established on the basis of the problems of similarly existing heat pumps.The equivalent temperature levels of typical evaporators are applied to the different heat sources of the proposed cycle,and the high-temperature heat sources are shown to enhance vapor injection.Then,the mathematical model and prototype are developed,and the results from experimental simulation and validation showed that the solar collector can improve the heating performance of the proposed heat pump system.In the middle-temperature heating period,the outdoor temperature is less than-25℃,and the average coefficient of performance(COP)value of the proposed heat pump was 4.2,which was greater than the COPs of conventional ground source heat pumps.展开更多
基金Supported by Major State Basic Research Development Program of China ("973" Program, No. 2009CB219907)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0936)
文摘Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.
文摘In this paper, the simulation approach and exergy analysis of multi-stage compression high tempera- ture heat pump （HTHP） systems with R1234ze（Z） working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120℃ pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compres- sion system. The multi-stage compression system has better energy and exergy etticiencies with the increase of compression stage number. Compared with the single- stage compression system, the coefficient of performance （COP） improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. When the waste heat source temperature is 60℃, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respec- tively.
基金supported by the Natural Science Foundation of Beijing Municipality(3172040)National Natural Science Foundation(51736008)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21050600)
文摘A new-type multiple-source heat pump cycle with two-stage compression was established on the basis of the problems of similarly existing heat pumps.The equivalent temperature levels of typical evaporators are applied to the different heat sources of the proposed cycle,and the high-temperature heat sources are shown to enhance vapor injection.Then,the mathematical model and prototype are developed,and the results from experimental simulation and validation showed that the solar collector can improve the heating performance of the proposed heat pump system.In the middle-temperature heating period,the outdoor temperature is less than-25℃,and the average coefficient of performance(COP)value of the proposed heat pump was 4.2,which was greater than the COPs of conventional ground source heat pumps.
