Analysis of the time-varying characteristics of frost properties in outdoor heat exchangers of heat pump air conditioner
The frost formation of outdoor heat exchanger is one of the important factors affecting the efficient operation of heat pump type air conditioner.The frost formation process of finned tube heat exchanger involved is affected by the structure and operating condition of heat exchanger,and there are obvious differences,which bring difficulties to the design of heat exchanger and system operation control.Based on the hypothesis of microsegment parameter averaging and distributed parameter method,the dynamic change of frost physical properties of finned heat exchangers under three frosting conditions were analyzed by using the frosting experiment results,and the influence of heat exchanger structure on frost physical properties were studied by comparing the data in the public literature.The results show that the variation trends of frost density,thickness and thermal conductivity are consistent with the theoretical prediction trend.The ratio of thermal conductivity to thickness approaches each other in the late frosting period,reaching about 300 W/(m2·K),indicating that the correlation between frost physical properties and heat exchanger structure and working conditions is weakened.The above results can provide a simplified method for frost prediction and operation control of finned tube heat exchangers.
国家科技期刊平台
NSTL
万方数据
