Theoretical And Experimental Study On A New Heat Pump System For Air Energy High Efficient Utilization

As a main kind of heat pump,air-source heat pump has the advantage of low cost,easy operation,good heating effect,safe and clean.EER of conventional air-source heat pump drops seriously when it operates in cooling condition with high ambient air temperature,as well,the system’s COP drops obviously caused by fin frosting when it operates in heating condition with low ambient air temperature and high ambient air relative humidity.To improve the disadvantages mentioned above,a novel replaced heat pump systems for air energy high efficient utilization was proposed.1.A cross-flow water-air mass and heat transfer model based on Poppe model was proposed.A direct evaporative heat exchanger-heat pump system was built to examine the accuracy of the model.According to the experimental data,it fitted the theoritical data well.The relative error of each testing point was totally lower than 20%.The system’s performance parameters in different weather conditions were accurately samulated.A new heat strengthen method with fillings’ layer seperation based on ε-NTU was proposed.Theoritical result showed that,the improvement could increase 30% more heat collection ability of the system in a particular situation.2.A new wet type indirect evaporative heat exchanger-heat pump system was created The new heat exchanger’s detailed design and production process were described in detail and the maneuverability was proved based on the model above.Under laboratory conditions,the system was operated in cooling and heating condition,respectively.The EER/COP-inlet air temperature curve with nine combinations of spray solution and inlet air volume flow rate was proposed.The same curve with four different inlet air relative humidity was also proposed.Experimental result showed the optimum combination of spray solution and inlet air volume flow rate was 2L/min,8000m3/h in cooling condition and 1L/min,10000m3/h in heating condition.EER increased with the decreasing of the inlet air relative humidity,and COP increased with the rising of the inlet air relative humidity.What’s more,the system operated well in cooling condition with high-temperature weather and easy-frosting weather in heating condition.A basic ecnomic analysis showed that the the new system’s payback period of investment was 0.56 year.