Field test investigation of the characteristics for the air source heat pump under two typical mal-defrost phenomena

作者：Wang W^*; Xiao J; Guo Q C; Lu W P; Feng Y C

来源：Applied Energy, 2011, 88(12): 4470-4480.

DOI：10.1016/j.apenergy.2011.05.047

• Air source heat pump
• Mal-defrost
• Heating efficiency
• Heating capacity

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.

• 出版日期2011-12
• 单位北京工业大学