Title of article :
Field test investigation of the characteristics for the air source heat pump under two typical mal-defrost phenomena
Author/Authors :
Wang، نويسنده , , W. U. Xiao Bing، نويسنده , , J. and Guo، نويسنده , , Q.C. and Lu، نويسنده , , W.P. and Feng، نويسنده , , Y.C.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2011
Abstract :
A study is presented on the characteristics of the air source heat pump (ASHP) under two kinds of typical mal-defrost phenomena. The definition of the “Mal-defrost phenomena” is put forward, and the possible origins of their occurrence are analyzed. It is concluded that the current defrost strategies may cause mal-defrost phenomena due to the lack of the direct control information, frost thickness. Transient characteristics of the tested ASHP under these mal-defrost phenomena are investigated by field tests. Instant frosting images are captured to record the dynamic frosting process. In the first phenomenon of mal-defrost, the defrost control is carried out over an hour after a “critical” level of frosting has been reached. It reduces the COP and heating capacity by about 17.4% and 29%, respectively. In the second phenomenon of mal-defrost, three defrost operations occur while almost no frost is observed on the heat exchanger during 6 h testing period. It causes 4.2% decrease for the heating efficiency.
Keywords :
Air source heat pump , Heating efficiency , Heating capacity , Mal-defrost
Journal title :
Applied Energy
Journal title :
Applied Energy