Experimental investigation on the multi-mode heat discharge process of a PCM heat exchanger during TES based reverse cycle defrosting using in cascade air source heat pumps
| Autor: | Tongyao Zhang, Minglu Qu, Yongbo Tang, Zhao Li, Jianbo Chen |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
020209 energy Nuclear engineering Energy Engineering and Power Technology 02 engineering and technology Thermal energy storage Industrial and Manufacturing Engineering Volumetric flow rate Refrigerant 020401 chemical engineering Defrosting Cascade Heat transfer Heat exchanger Air source heat pumps 0202 electrical engineering electronic engineering information engineering 0204 chemical engineering |
| Zdroj: | Applied Thermal Engineering. 151:154-162 |
| ISSN: | 1359-4311 |
| Popis: | Thermal energy storage (TES) based reverse cycle defrosting method has been proposed to solve the defrosting problem for cascade air source heat pumps (CASHPs), with the benefits of shortening defrosting duration and continuously supplying heat to indoor space. During TES based reverse cycle defrosting, the high temperature (HT) cycle and low temperature (LT) cycle of a CASHP unit share the same heat source, i.e., the PCM-heat exchanger (PCM-HE). Considering the different operating conditions in HT and LT cycle, the PCM will undergo multi-mode heat discharge process. In this paper, RT 10 is used as PCM in a finned-tube heat storage unit, and the multi-mode heat discharge process was experimentally investigated under the frosting condition of −12 °C and 85% RH. The results suggested that the heat transfer rate to LT cycle was higher than that to HT cycle, caused by higher temperature difference between LT cycle and PCM and LT refrigerant flowrate. The calculated heat provided to HT and LT cycle accounted for 37.7% and 62.3% of the heat released by the PCM-HE, respectively. Furthermore, the distribution pattern of the heat provided to the HT/TL cycle was explored under different outdoor frosting conditions with the same amount of frost. |
| Databáze: | OpenAIRE |
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