As an environmentally harmless and feasible alternate refrigerant, CO 2 has attracted worldwide attention, especially in the area of automobile air conditioning (AAC). The thermal property of CO 2 and its trans cr...As an environmentally harmless and feasible alternate refrigerant, CO 2 has attracted worldwide attention, especially in the area of automobile air conditioning (AAC). The thermal property of CO 2 and its trans critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO 2 system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO 2 AAC system.展开更多
Currently, the refrigerant used in the automotive air conditioning system is R134 a which has a high global warming potential(GWP) value, so people are eager to find a good replacement for it. According to recent stud...Currently, the refrigerant used in the automotive air conditioning system is R134 a which has a high global warming potential(GWP) value, so people are eager to find a good replacement for it. According to recent studies, R1234 yf is considered as one of the top candidates to replace R134 a. In this article, the performances of R1234 yf "drop-in" system and the optimization to the R1234 yf system are experimentally studied and investigated.The expansion valve used for the R1234 yf system is optimized by changing the charged fluid and adjusting the spring force. The results indicate that it can improve the performance of R1234 yf system significantly through adjusting the thermostatic expansion valve. For the thermostatic expansion valves(TEVs) charged with R134 a in thermal bulb, the system performance is optimal. Compared to the original expansion valve, for the R1234 yf system applying the adjusted expansion valves, under different working conditions the cooling capacity increases by 11.3% averagely and the coefficient of performance(COP) increases by 8% averagely.展开更多
文摘As an environmentally harmless and feasible alternate refrigerant, CO 2 has attracted worldwide attention, especially in the area of automobile air conditioning (AAC). The thermal property of CO 2 and its trans critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO 2 system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO 2 AAC system.
基金the National Key Technologies Research and Development Program of China During the 12th Five-Year Plan Period(No.SQ2011GX03D03999)
文摘Currently, the refrigerant used in the automotive air conditioning system is R134 a which has a high global warming potential(GWP) value, so people are eager to find a good replacement for it. According to recent studies, R1234 yf is considered as one of the top candidates to replace R134 a. In this article, the performances of R1234 yf "drop-in" system and the optimization to the R1234 yf system are experimentally studied and investigated.The expansion valve used for the R1234 yf system is optimized by changing the charged fluid and adjusting the spring force. The results indicate that it can improve the performance of R1234 yf system significantly through adjusting the thermostatic expansion valve. For the thermostatic expansion valves(TEVs) charged with R134 a in thermal bulb, the system performance is optimal. Compared to the original expansion valve, for the R1234 yf system applying the adjusted expansion valves, under different working conditions the cooling capacity increases by 11.3% averagely and the coefficient of performance(COP) increases by 8% averagely.
