Experimental Study on Frost Growth and Dynamic Performance of Air Source Heat Pump System
The frosting process on the fin-tube evaporator and its effects on the dynamic performance of an air source heat pump (ASHP) were investigated experimentally. The frost thickness was measured by using micro-photograph, and the frost accumulation mass was estimated in terms of the difference in measured humidity before and after the test evaporator. The experimental results indicate that the frost layer grows in a manner of three stages. In the initial frosting stage, the frost grows quickly and the performance of the ASHP unit is slightly improved. After the initial stage,the frost thickness growth rate decreases with the frosting time, the performance and the refrigerant-side parameters of the ASHP system are only slightly affected by frosting on the outdoor coils. In the third frosting stage the frost thickness growth rate increases sharply to about 3-5 times that in the second stage, and the performance of the ASHP unit decays rapidly. Observation on the frost layer suggested that the rapid decrease in the performance of the ASHP unit is caused by the morphological variation of the frost crystals. It was found in the experiments that the duration of the second frosting stage is significantly affected by the outdoor air relative humidity,but these of the initial and the third frosting stages are nearly invariable for the outdoor air relative humidity ranging from 65％ to 85％ with a constant outdoor air temperature. At the meantime, it was found that the peak frosting outdoor air temperature, under which the frost layer grows most quickly with the frosting time for a constant outdoor air relative humidity, is about 0℃ over all of the test outdoor air relative humidity for the test ASHP unit.
Air source heat pump Frosting Dynamic performance Frost growth Frost Thickness Experiment
Guo X M Chen Y G Wang W H Chen C Z
Energy and Power Engineering,Xian Jiaotong University,Xian 710049,P.R.China;School of Mechanical E School of Mechanical Engineering,Tianjin University of Commerce,Tianjin 300134,P.R.China Energy and Power Engineering,Xian Jiaotong University,Xian 710049,P.R.China
国际会议
上海
英文
476-482
2008-04-05（万方平台首次上网日期，不代表论文的发表时间）