Mathematical Study On The Thermal Performance Of The Aluminum Radiant Plate Condenser For Heat Pump Room Air Conditioners

The air source heat pump is a kind of clean,efficient and mature heating method,which plays an important role in promoting the clean heating in winter in northern china.The air source heat pump usually works with the convective indoor heat exchanger coupled with the air fan,but this kind of indoor air conditioner has the poor thermal comfort.Hot air delivered by traditional heat pump air conditioners would accelerate the evaporation of sweat on human skin surface,and produce the strong draught.At the same time,in order to avoid the feeling of the cold blow,the supplied air temperature and condensation temperature are relatively high,while the vertical temperature difference of indoor air is high too,which causes high energy consumption.In addition,indoor fans also have the problem of noise and increased energy consumption.According to the problems above,a novel radiant plate indoor condenser with aluminum alloy shell,and heat storage medium filled in between,was proposed.This paper carried out a mathematical modeling research on heat exchange performance of this condenser,and would provide scientific and effective basis for its optimal design.The condenser is composed of copper tubes,heat storage medium and the aluminum alloy shell.Based on the structure and heat transfer mechanism of the condenser,the physical and mathematical models of the heat transfer process were established,and Particle Swarm Optimization as the method of solving the equations was introduced.Besides,the experimental data were used to verify the mathematical model.The verification results showed that under the condition of the condensation temperature of 44.5 ℃,refrigerant mass flow of 41.4 kg/h and the indoor air temperature of 18 ℃,the measured heat exchange was 1838 W,while the simulated value was 1813 W,with the relative error of 1.4%.Subsequently,when the condensation temperature was between 36.2 and 52.5 ℃,the flow rate was between35.5 and 55 kg/h,and the indoor air temperature was between 16 to 22 ℃,the relative deviation between the simulated heat exchange and the measured heat exchange ranged from-1.5%to 3.4%.The model was proved to be correct and can be applied to simulate the heat transfer performance of the condenser.Finally,within the working conditions of refrigerant mass flow rate ranging from 39.8 to 41.8 kg/h,the length of the copper tube ranging from 10.8 m to 12 m,condensing temperature from 40 to 44 ℃ and indoor temperature from 18 to 22.1 ℃,simulation research was conducted,whose errors were within±3.4%.The influence of tube length,condensing temperature,refrigerant mass flow rate and indoor air temperature on heat exchange of radiant plate aluminum condenser,respectively,was simulated through the mathematical model verified by experimental data.The results of response surface analysis showed that the tube length,followed by the refrigerant flow rate,had the most significant effect on the heat transfer effect of condenser.