Vapor Injection Parameter Analyses And Performance Optimization On Enhanced Vapor Injection Air-source Heat Pump System Using R32

R32 air-source heat pump system is able not only to overcome the difficulties that conventional heat pump faced when operating at low ambient temperature,but also to satisfy the needs of heating in cold regions.Compared with the ordinary air source heat pump,the air injection enthalpy heat pump adds a feeding loop with economizer,and the compressor adds a middle air outlet,so the design and operation of the system is more complicated than the ordinary heat pump.In this paper,the effects of ambient temperature,quasi-first-order compression volume ratio and air injection pressure on relative air injection volume are determined and the effects of relative air injection volume during operation on system performance are studied.According to the working principle of air-injet enthalpy-increasing heat pump and the analysis of air-filling process,the mathematical model of thermodynamic circulation of the system is established.MATLAB software was used to write the calculation program,and the reliability of the system model was verified according to the experimental data in the literature.The two trends were the same,and the error was within the allowable range,that is,the model was reliable and accurate.Then,when the evaporation temperature is-20~0? and the condensation temperature is 45?,the main performance parameters of the air-injet enthalpy heat pump system and the ordinary air-source heat pump system at different ambient temperatures are simulated and compared,and the calculation results show that the performance of the air-injet enthalpy heat pump system is better than that of the ordinary heat pump system.At the same time,At the same time,the heating performance of R32 refrigerant and R22 refrigerant in the heat pump system is calculated.It is found that R32 refrigerant is more suitable for promotion in low temperature area than R22 refrigerant.By adjusting the air supply pressure of the system and the content product ratio of the quasi-first-stage compression,the relative air injection quantity of the system is changed,and then the optimal operating range of the heating mode of the air injection enthalpy increasing heat pump system is obtained.The results show that the specific volume ratio of the first-stage compression of the system is 1.1,When the ambient temperature is below-10?,the optimal relative injection volume is 22%-33%.When the ambient temperature is within-10~-5 ?,the optimal relative air injection volume is 20%-22%.When the ambient temperature is above-5?.The corresponding optimal relative inject pressure is between 0.85-1.21.In the range of optimal air replenishment parameters,the advantages of the R32 enhanced vapor injection air-source heat pump system are obvious.Under summer cooling conditions,the quasi-first-stage compression internal volume ratio should not be too large for the jet-enhanced enthalpy heat pump system.When the value is 1.1,the refrigeration performance is better,and the system's best jet volume is 0.14-0.2 Room is more suitable.In the range of the best supplementary gas parameters,compared with the ordinary heat pump system,the advantages of the air injection enthalpy-increasing heat pump system are more obvious.The results show that the heat pump system can improve the heat pump performance coefficient.The system has the optimal quasi-first-order compression content product ratio,and has the optimal relative air injection pressure and the optimal range of relative air injection volume in operation.It can select the appropriate operating parameters according to different ambient temperatures,providing reference for the design and application of the air-source heat pump system with air injection enthalpy increase.