| With the rapid economic growth,the importance of environmental issues has gradually increased.Since the inclusion of HFCs as greenhouse gases after the Kyoto Protocol,and the accelerated phase-out of HCFCs adjustment case and carbon neutral program adopted by the 19 th Meeting of the Parties to the Montreal Protocol,all of them are requirements for the emission of greenhouse gases,and the status of environmentally friendly refrigerants has gradually increased.In the global air conditioning and refrigeration industry,choosing alternative environmentally friendly refrigerants with zero ODP and low GWP value has become a difficult task.At present,R410 A is mostly used in China’s domestic air-conditioning market,and R32,which is a component of R410 A,has better performance in environmental protection.At the same time,with the increasing price of copper,the production cost of enterprises has also leaped high.In order to solve the above problems,this paper focuses on the comparative experimental study of the circulating performance of R32 refrigerant in household air conditioners with Φ 5mm indoor heat exchanger to provide a solid foundation for the promotion and application of R32 household heat pump air conditioners.Based on the analysis of the thermal properties of R32 and R410 A,an experimental setup for testing the performance of R32 and R410 A split type domestic air source heat pumps was built.In the enthalpy difference laboratory,experimental studies on the operating characteristics of R32 and R410 A split domestic air source heat pump systems were conducted,including: rated cooling,low temperature cooling,intermediate cooling,low temperature intermediate cooling,rated heating,intermediate heating,and low temperature heating under 7 different operating conditions of 5mm indoor heat exchanger R410 A heat pump system and R32 heat pump system operating characteristics.The experimental study of the operating characteristics of 7mm indoor heat exchanger and5mm indoor heat exchanger R32 heat pump system under the above seven operating conditions;the experimental study of the influence of refrigerant charge,compressor speed,fan speed and other factors on the operating characteristics of 5mm indoor heat exchanger R32 domestic air source heat pump system under rated cooling and rated heating conditions.The following conclusions can be drawn from the experimental data analysis:(1)the cooling(heating)capacity of the 5mm indoor heat exchanger R32 domestic air source heat pump system is higher than that of the R410 A system under seven operating conditions;the cooling(heating)power consumption is lower than that of the R410 A system;the EER/COP is higher than that of the R410 A system;the compressor discharge temperature is slightly higher than that of the R410 A system.the APF(annual The APF(annual energy consumption efficiency)of R32 system(4.77)is 4% higher than that of R410 A.The experimental data analysis shows that the 5mm indoor heat exchanger R32 domestic air source heat pump system has better performance than the R410 A system.(2)For R32 domestic air source heat pump system,in addition to low temperature heating conditions,in the other six operating conditions,5mm indoor heat exchanger heat pump system cooling(heat)capacity is slightly lower than the 7mm system;the cooling(heat)power consumption is lower than that of the 7mm system;the opposite is true for the low temperature heating condition.5mm system has a slightly lower EER/COP than the 7mm system in the rated cooling,low temperature cooling,rated heating and intermediate heating conditions;the intermediate cooling and heating conditions;and the EER/COP is slightly lower than that of the 7mm system.The EER/COP of the 5mm system is slightly lower than that of the 7mm system;the EER of intermediate cooling is the same as that of the 7mm system;the COP of low-temperature intercooling and low-temperature heating is higher than that of the 7mm system.the exhaust temperature of the 5mm system is lower than that of the 7mm system under all seven operating conditions.the APF of the 5mm system(4.77)is basically the same as that of the 7mm system(4.79).The analysis of experimental data shows that the use of 5mm indoor heat exchanger,the system energy efficiency ratio is not significantly reduced,and the system operating characteristics are better.(3)Rated cooling and rated heating conditions,the compressor frequency increases,5mm indoor heat exchanger R32 home air source heat pump system cooling(heat)and cooling(heat)power consumption rose,EER/COP first rose and then fell.The analysis of the experimental results shows that the optimal frequency point for the rated cooling and rated heating conditions of the system is 53HZ and 72HZ,respectively.(4)Under the rated cooling and rated heating conditions,the internal fan speed increases,the cooling(heat)capacity and cooling(heat)power consumption of the 5mm indoor heat exchanger R32heat pump system rises,and the EER/COP rises and then falls.Under the rated cooling and rated heating conditions,the system performance is optimal when the internal fan speed is 1600 rpm and 1725 rpm,respectively.(5)Under the rated cooling and rated heating conditions,the system cooling(heat)capacity and cooling(heat)power consumption increase with the increase of external fan speed,EER increases and then decreases,and COP decreases with the increase of speed.Under the rated cooling and rated heating conditions,the system performance is optimal when the external fan speed is800rpm and 950rpm.(6)Under the rated cooling and rated heating conditions,the cooling capacity and cooling power consumption of 5mm indoor heat exchanger R32 heat pump system increased with the increase of R32 charge;the heating capacity and heating power consumption increased and then decreased and then stabilized;EER/COP increased and then decreased.The analysis of the experimental results shows that the system performance is optimal under the rated cooling condition with the charging quantity of600g. |
PDF Full Text Request