Operation Mechanism And Experimental Stady On Air Source Heat Pump With Natural Cooling Source

Vapor-injected air-source heat pump system using injection subcooling can effectively solve the problem that the heat pump performance is low and the exhaust gas temperature rises too quickly when the heat pump operates under low temperature and ultra low temperature conditions,and the stability of the system has been improved.In this paper,according to the circulation mechanism and research status of the quasi two-stage compression system,the circulation mechanism of vapor-injected air-Source heat pump system using injection subcooling has been proposed.The method is adopted that using a combination of theoretical analysis and experimental verification,the system performance has been studied and analyzed in detail.First of all,the reasons for the low heating performance of the air source heat pump during the low temperature conditions in winter has been analyzed.At present,scholars at home and abroad have summarized the research progress of cryogenic heat pump and subcooling of refrigerants.Then,this article is based on vapor-injected air-source heat pump system using injection subcooling,using a combination of theoretical analysis and experimental verification.The effect of subcooling on the heat,power,and energy efficiency of heat pumps with low ambient temperature under different conditions of a particular refrigerants,which are based on the theory of the heat transfer and engineering thermodynamics.The heating performance of the air source heat pump system with natural cold source supplemented with air and cold air was studied in detail during the cold winter conditions.A mathematical calculation model was established for the subcooling replenishment performance in the system,and the theoretical cycle calculation of the subcooling replenishing system was completed.From theoretical calculations,it can be seen that vapor-injected air-source heat pump system using injection subcooling can obtain lower exhaust temperature and higher heating performance than single-stage compression system and two-stage compression system with vapor injection.Theoretically,this system has further breakthroughs in solving the problem of low temperature adaptability of air source heat pump systems.Finally,an experimental verification test was conducted.The circulation principle of vapor-injected air-source heat pump system using injection subcooling was proposed and the R32 experimental system has been done.Based on the theoretical analysis,the operational mechanism and experimental scheme of quasi two-stage compression vapor-injected air-source heat pump system using injection subcooling have been analyzed.The variation of heat pump system with sub-cooling mass flow,vapor injection pressure and evaporating temperature has been discussed under low temperature heating conditions.Also,compression system of R32 vapor-injected heat pump using injection subcooling has been compared with single-stage compression system and two-stage compression system with vapor injection.The results show that,under the same conditions,the vapor-injected air-source heat pump system using injection subcooling can effectively reduce the exhaust temperature of the compressor,and the consumed electric power has been lower than the single-stage compression system;the heat performance has been significantly improved.The exhaust gas temperature has been reduced compared to the two-stage compression system with vapor injection,but the heating performance has been reduced slightly.However,the vapor-injected air-source heat pump system using injection subcooling can maintain lower exhaust temperature and higher heating performance under the low temperature conditions below-20?,and can meet the requirements of low temperature conditions in the actual operation.This shows that the Vapor-injected air-source heat pump system using injection subcooling has a certain advantage of low temperature adaptation.