Research On Heating And Cooling Comfort Of Refrigerant-heated Radiator Coupled With Air Source Heat Pump

With the development of the economy and the improvement of living standards,people are paying more and more attention to the thermal comfort of the building indoor environment.As a clean and sustainable technology,air source heat pump system has been widely used in recent years.Air conditioners are the most popular household air source heat pump technology.However,Air conditioners have the shortcomings such as draught and noise.In order to solve these problems,a refrigerant-heated radiator coupled with air source heat pump has been developed.This paper aims to study the heating and cooling comfort of the refrigerant-heated radiator and guide its plate design.First,the indoor thermal environment models using the refrigerant-heated radiator and the air conditioner are established.The Fluent simulation software is used to solve the model.Meanwhile,experiments are conducted to verify the accuracy and reliability of the indoor thermal environment model.PMV-PPD and LPD evaluation indexes are adopted to analyze the thermal comfort of occupants and are calculated by the Matlab software.Then,using the established indoor heat exchanger model,the comfort of the refrigerant-heated radiator and the air conditioner during heating and cooling is compared and analyzed.Research shows that the thermal comfort of the refrigerantheated radiator has higher air temperature at the ankle,smaller vertical temperature difference and lower dissatisfaction rate than the air conditioner during heating condition.Meanwhile,in the case of cooling,air conditioner can achieve lower indoor air temperature and smaller vertical temperature difference,but the draft sensation is higher than the radiator.Besides,the overall thermal dissatisfaction of the refrigerantheated radiator is lower than the air conditioner and the distribution of the former is more uniform.Finally,the influence of the aspect ratio on the heating and cooling comfort of the refrigerant-heated radiator is studied.For heating condition,as the aspect ratio of length to height grows from 0.45 to 5,the PPDs of seated and standing occupants decrease from 21.07% and 20.22% to 7.74% and 7.23%,respectively.The local dissatisfaction rates caused by vertical temperature difference and floor temperature both decrease,and that caused by draft sensation is not much changed.During cooling condition,as the aspect ratio of length to height grows from 0.45 to 5,the PPDs of seated and standing occupants decrease from 7.02% and 7.07% to 5.00% and 5.00%,respectively.Meanwhile,local dissatisfaction rates increase but still meet the first-level requirements.The aspect ratio of this radiator with the best comfort is 3.71～5.In practical applications,better indoor thermal comfort can be achieved by increasing the aspect ratio of length to height.