Experimental Study On Heating Performance Of Wall Panel With Direct Expansion Air Source Heat Pump

Air source heat pump heating is a common heating way in the South at present.Moreover,the air source heat pump heating has ushered in the golden age of development with the support of the big environment and national policy.However,the conventional air source heat pump generally has a problem of poor thermal comfort.Considering the advantages of a radiant heating system with higher thermal comfort,a new type of heating end was presented which heated by means of radiation and forced convection heat transfer in this paper.In addition,this article designed a wall panel heating system with direct expansion air source heat pump and experimentally analyzed the operation performance of the system.Based on the design method of conventional radiant heating end and air source heat pump air conditioner end,the radiant panel in wall which used refrigerant as a heat medium was designed in this article.Then,the outdoor unit of the existing conventional air source heat pump air conditioner was refitted and the experimental platform of the wall panel heating system with direct expansion air source heat pump was set up.Moreover,the calculation results of the experimental error showed that the measured data conformed to the requirements of experimental accuracy.Based on the experimental platform built,the heating and defrosting experiments of the wall panel heating system with direct expansion air source heat pump were carried out.The change law of characteristic parameters such as suction and exhaust pressure of the compressor,inlet and outlet temperature of radiant panel,heating capacity,compressor power,COP and so on were studied.Moreover,the influence of outdoor environment temperature and air supply rate of radiant panel on thermal performance of the system were analyzed.In addition,the characteristic parameters such as indoor temperature,inlet and outlet temperature of radiant panel,defrosting duration,resuming heating duration,defrosting energy efficiency ratio and so on were also studied during defrosting process.Besides,the defrosting performance and the influence of defrosting on the indoor thermal environment were analyzed respectively.The experimental results indicated that the COP of the system tended to stabilize between 2.90 and 3.02 under rated heating condition and the wall panel heating system with direct expansion air source heat pump was more efficient compared with the central heating system.Moreover,with the increase of outdoor environment temperature,the heating capacity and the COP of the system increased.Besides,the radiative heat transfer and the forced convection heat transfer ratio could be effectively regulated by adjusting the air supply rate of the radiant panel.In addition,compared with the conventional air source heat pump system,the system had obvious improvement on defrosting time,the influence on indoor thermal environment and defrosting energy efficiency ratio during defrosting process.The research work of this article will provide a useful reference for optimizing the design of the wall panel heating system with direct expansion air source heat pump and improving the deterioration of the indoor thermal environment in the process of heating with conventional air source heat pump.