| Autor: |
Y.C. Feng, W.P. Lu, Jing Xiao, Wei Wang, Qingci Guo |
| Rok vydání: |
2011 |
| Předmět: |
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| Zdroj: |
Applied Energy. 88:4470-4480 |
| ISSN: |
0306-2619 |
| DOI: |
10.1016/j.apenergy.2011.05.047 |
| Popis: |
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. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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