Performance of an Air Source Heat Pump Water Heater using Different Electronic Expansion Valve Control Methods
Because of the requirement of annual operation, an air source heat pump water heater has complex and variable working conditions. Therefore, there are higher requirements for air source heat pump water heater system control. Based on the flexible adjustment characteristics of the electronic expansio...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Journal of Refrigeration Magazines Agency Co., Ltd.
2019-01-01
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| Series: | Zhileng xuebao |
| Subjects: | |
| Online Access: | http://www.zhilengxuebao.com/thesisDetails#10.3969/j.issn.0253-4339.2019.06.070 |
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| Summary: | Because of the requirement of annual operation, an air source heat pump water heater has complex and variable working conditions. Therefore, there are higher requirements for air source heat pump water heater system control. Based on the flexible adjustment characteristics of the electronic expansion valve, this study proposes a simple control method of the fixed discharge superheated temperature. Meanwhile, the control methods of a fixed valve opening and fixed superheated temperature were used to conduct experimental research and analyze their internal process. When the ambient temperature is 22 ℃，the experimental results show that the discharge temperature dramatically decreased under the control methods of a fixed valve opening; however, its coefficient of performance (COP) is the lowest and its compression risk with liquid is high. Although the COP is the highest under the control method of a fixed superheated temperature, the discharge temperature is also the highest. Under the control method of a fixed discharge superheated temperature, its COP is slightly lower than that of the fixed superheated temperature control method. However, the discharge temperature is effectively reduced by nearly 7 K on average. Meanwhile, compared to the fixed valve opening, its average COP increased 4.9% and the risk of compressor suction with a large amount of liquid refrigerant can be avoided. Therefore, this method effectively combines the advantage of the other two methods. |
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| ISSN: | 0253-4339 |