目前电动汽车热泵空调系统制冷剂绝大多数为R134a,受限于制冷剂本身物性,当外界温度较低时,系统制热量衰减明显。本文采用混合制冷剂以改良热泵系统的制热性能,分析了压缩机在不同转速、不同混合比例下R134a/R32混合制冷剂在汽车空调中...目前电动汽车热泵空调系统制冷剂绝大多数为R134a,受限于制冷剂本身物性,当外界温度较低时,系统制热量衰减明显。本文采用混合制冷剂以改良热泵系统的制热性能,分析了压缩机在不同转速、不同混合比例下R134a/R32混合制冷剂在汽车空调中的制热性能。相对于R134a系统,混合制冷剂空调系统制热量增加约14.0%～17.1%,性能系数(Coefficient of Performance,COP)提升4.3%～14%。当混合制冷剂中R32的质量分数为4%时,系统COP最佳,同时制热量提升明显。展开更多
The heating performance of a water-to-refrigerant type ground source heat pump system is represented in this paper under the actual working conditions of the GSHP(ground source heat pump) system during the winter seas...The heating performance of a water-to-refrigerant type ground source heat pump system is represented in this paper under the actual working conditions of the GSHP(ground source heat pump) system during the winter season of 2008.Ten heat pump equipments with the capacity of 10 HP each and a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth were constructed.We investigated a variety of working conditions,including the outdoor temperature,the ground temperature,and the water temperature of inlet and outlet of the ground heat exchanger in order to examine the heating performance of the GSHP system.Subsequently,the heating capacity and the input power were investigated to determine the heating performance of the GSHP system.The average heating coefficient of performance(COP) of the heat pump was noted to be 5.1 at partial load of 47%,while the overall system COP was found to be 4.2.Also,performance of the GSHP system was compared with that of air source heat pump.展开更多
A single cylinder rotary compressor was applied in the refrigerant injection air-source heat pump to improve the heating performance in cold regions. In this study, the performance of an R410 A single cylinder rotary ...A single cylinder rotary compressor was applied in the refrigerant injection air-source heat pump to improve the heating performance in cold regions. In this study, the performance of an R410 A single cylinder rotary compressor vapor injection(SCRCVI) system was measured and analyzed by varying the compressor frequency f and injection pressure Pi njat the ambient temperature To d=–10°C.The experimental results indicated that an optimum injection pressure to gain the maximum COP_h (coefficient of performance) existed in the SCRCVI cycle. However, the maximum COP_h of the SCRCVI system decreased as the increase of the frequency, and the maximum COPhwas even lower than that of the CSVC system at high compressor frequency. Therefore, in view of the energy saving and emission reduction, the SCRCVI system should be switched to single stage compression system when the heating capacity demand could be satisfied at high compressor frequency f. Compared to the conventional single-stage vapor compression(CSVC) system, refrigerant injection could enhance the heating capacities and COP_h by 28.2% and 7.91%, respectively. The average total mass flow rate of the SCRCVI system was 24.68% higher than that of the CSVC system. As the SCRCVI system worked at the optimum injection pressure, the variation trends of the different system parameters were investigated in detail. These trends were reliably used to optimize the refrigerant injection system design and the control strategy. The parameter of(P_(inj)–P_s) could be adopted as the signals to control the opening of the upper stage electronic expansion valve EEV1.展开更多
Due to the poor heating performance and operating safety in low ambient temperature,traditional Air Source Heat Pump(ASHP)for Electric Vehicles(EVs)has many limits in cold region,which can be solved by the ASHP with r...Due to the poor heating performance and operating safety in low ambient temperature,traditional Air Source Heat Pump(ASHP)for Electric Vehicles(EVs)has many limits in cold region,which can be solved by the ASHP with refrigerant injection.During the start-up stage of EV in winter,the inlet air temperature of the in-car condenser is the same as the ambient temperature.At this situation,the performance and control strategy of the heat pump require special attention.In the present study,a series of experiments were carried out on the heating performance of the Refrigerant Injection Heat Pump(RIHP)system in start-up stage of EV,at the ambient temperature from–20℃ to–5℃.The effects of compressor speed and injected refrigerant state on the heating performance of the system were discussed in depth.According to the results,the control strategies during start-up stage have been discussed in the end of the article.The study provides a practical control strategy for the RIHP system during the start-up stage of electric vehicles,helping to efficiently operate electric vehicles in cold regions.展开更多
文摘目前电动汽车热泵空调系统制冷剂绝大多数为R134a,受限于制冷剂本身物性,当外界温度较低时,系统制热量衰减明显。本文采用混合制冷剂以改良热泵系统的制热性能,分析了压缩机在不同转速、不同混合比例下R134a/R32混合制冷剂在汽车空调中的制热性能。相对于R134a系统,混合制冷剂空调系统制热量增加约14.0%～17.1%,性能系数(Coefficient of Performance,COP)提升4.3%～14%。当混合制冷剂中R32的质量分数为4%时,系统COP最佳,同时制热量提升明显。
文摘The heating performance of a water-to-refrigerant type ground source heat pump system is represented in this paper under the actual working conditions of the GSHP(ground source heat pump) system during the winter season of 2008.Ten heat pump equipments with the capacity of 10 HP each and a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth were constructed.We investigated a variety of working conditions,including the outdoor temperature,the ground temperature,and the water temperature of inlet and outlet of the ground heat exchanger in order to examine the heating performance of the GSHP system.Subsequently,the heating capacity and the input power were investigated to determine the heating performance of the GSHP system.The average heating coefficient of performance(COP) of the heat pump was noted to be 5.1 at partial load of 47%,while the overall system COP was found to be 4.2.Also,performance of the GSHP system was compared with that of air source heat pump.
基金supported by the South Wisdom Valley Innovative Research Team Program(serial number:Shunde District of Foshan City Government Office [2014] No.365)the 2017 Guangzhou Collaborative Innovation Major Projects(Grant Nos.201604016048 and 201604016069)
文摘A single cylinder rotary compressor was applied in the refrigerant injection air-source heat pump to improve the heating performance in cold regions. In this study, the performance of an R410 A single cylinder rotary compressor vapor injection(SCRCVI) system was measured and analyzed by varying the compressor frequency f and injection pressure Pi njat the ambient temperature To d=–10°C.The experimental results indicated that an optimum injection pressure to gain the maximum COP_h (coefficient of performance) existed in the SCRCVI cycle. However, the maximum COP_h of the SCRCVI system decreased as the increase of the frequency, and the maximum COPhwas even lower than that of the CSVC system at high compressor frequency. Therefore, in view of the energy saving and emission reduction, the SCRCVI system should be switched to single stage compression system when the heating capacity demand could be satisfied at high compressor frequency f. Compared to the conventional single-stage vapor compression(CSVC) system, refrigerant injection could enhance the heating capacities and COP_h by 28.2% and 7.91%, respectively. The average total mass flow rate of the SCRCVI system was 24.68% higher than that of the CSVC system. As the SCRCVI system worked at the optimum injection pressure, the variation trends of the different system parameters were investigated in detail. These trends were reliably used to optimize the refrigerant injection system design and the control strategy. The parameter of(P_(inj)–P_s) could be adopted as the signals to control the opening of the upper stage electronic expansion valve EEV1.
基金support by the National Natural Science Foundation of China(No.51576203)。
文摘Due to the poor heating performance and operating safety in low ambient temperature,traditional Air Source Heat Pump(ASHP)for Electric Vehicles(EVs)has many limits in cold region,which can be solved by the ASHP with refrigerant injection.During the start-up stage of EV in winter,the inlet air temperature of the in-car condenser is the same as the ambient temperature.At this situation,the performance and control strategy of the heat pump require special attention.In the present study,a series of experiments were carried out on the heating performance of the Refrigerant Injection Heat Pump(RIHP)system in start-up stage of EV,at the ambient temperature from–20℃ to–5℃.The effects of compressor speed and injected refrigerant state on the heating performance of the system were discussed in depth.According to the results,the control strategies during start-up stage have been discussed in the end of the article.The study provides a practical control strategy for the RIHP system during the start-up stage of electric vehicles,helping to efficiently operate electric vehicles in cold regions.
