| The solar energy + air source heat pump with electric coupling direct condensing floor radiant heating is different from the conventional hot water type floor radiant heating air source heat pump from the following three aspects: 1.The defrosting method is different.The coupling system performs multi-system alternating parallel defrost through electric auxiliary equipment,solar coating,floor condensing heat storage and compressor reverse circulation,which is different from single reverse circulation defrost method;2.Different heating end forms.The coupling system adopts the direct condensing floor radiant heating end,and the refrigerant in the capillary copper tube directly transfers the heat to the floor,and the hot water type floor radiant heating end needs secondary heat transfer through the water medium;3.The heat transfer method of evaporator is different.The solar energy + air energy outdoor heat exchanger enhances the heat radiation heat transfer performance of the heat exchanger by means of the selective solar energy absorption coating,which is different from the conventional heat transfer mode of tube fin convection heat transfer.In summary,the new coupling system has better defrosting performance.Compared with the conventional air source heat pump,it can save more defrosting energy.The new coupling system has a primary energy utilization rate of 1.20,and the energy saving effect is obvious.In this paper,the new coupled system component model,heating operation model,frosting model and defrosting operation model simulation program after modifying the mathematical model are established by using MATLAB software.The construction process of the system model is elaborated,and the GUI operation interface is given.The experimental platform revised and verified the accuracy of the simulation program.Among them,the initial error of the frost layer growth calculated by the simulation program is about 8%,the condensation temperature is about 6.2% error,and the evaporator surface temperature is about 5.2% error.The simulation program laid the theoretical foundation for subsequent research.This paper optimizes the installation position and installation power of the electric auxiliary heating equipment,and proposes the system operation flow of the new coupling system with or without irradiance.It points out the calculation method of the theoretical calculation electric defrosting device power and the evaluation system of anti-perfect frosting FRC..Through the experimental test of different installation positions and different powers of the electric auxiliary equipment,the effects of FRC,indoor thermal comfort,total defrost energy consumption and defrost time in different situations were compared;it was found that the electric heating equipment increased by 20 W each time.FRC is reduced by 2%;installation on the outdoor side or indoor side will improve indoor thermal comfort,and the effect of installing on the indoor side is obvious;the installation of electric auxiliary equipment contributes to the total de-frost energy consumption and defrosting time reduction,however Installation on the outdoor side is more conducive to the improvement of the system's defrosting performance;when the outdoor side installation power reaches 80 W,the defrosting time is reduced by 36.5%,and the defrosting energy consumption is reduced by 35.2%.The effects of hot water end and straight condensation end on defrosting performance were analyzed.The hot water type end has a large heat transfer coefficient under the defrosting condition,and the defrosting time is also short;the straight condensing type end has a long defrosting time and a defrosting period,and the refrigerant flow rate change is relatively stable.The system operates relatively smoothly and reliably.In contrast,straight-condensed end defrosting performance provides higher room for defrosting performance.The overall operating performance of the new coupled system was explored.In view of the frosting of the outdoor unit of the new coupling system,the experiment recorded a frosting condition and combined the frosting of different surfaces,and found the influence of the irradiance on the frosting condition.When the instantaneous irradiance exceeds 250 W/m2,Will affect the frost layer.The performance of the new coupled system was calculated by the simulation program.The comprehensive analysis showed that the defrost cycle of the new coupled system was about 9 times that of the conventional type,the defrosting time was 2.3 times that of the conventional type,and the total energy consumption of defrosting only accounted for 22.2% of the conventional type.In summary,the new coupling system has better defrosting performance.Compared with the conventional reverse circulation defrosting method,it can save more defrosting energy consumption,and its primary energy utilization rate also reaches 1.20,and the energy saving effect is obvious. |
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