Experimental performance analysis of a CO2 direct-expansion solar assisted heat pump water heater
| Autor: | Luiz Machado, Sabrina Nogueira Rabelo, Juan Jose Garcia Pabon, Tiago de Freitas Paulino, Willian Moreira Duarte |
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| Rok vydání: | 2021 |
| Předmět: |
Overall pressure ratio
business.industry 020209 energy Mechanical Engineering Refrigeration 02 engineering and technology Building and Construction Mechanics 021001 nanoscience & nanotechnology Solar energy Thermographic camera law.invention Radiation flux law Heat exchanger 0202 electrical engineering electronic engineering information engineering Environmental science Relative humidity 0210 nano-technology business Heat pump |
| Zdroj: | International Journal of Refrigeration. 125:52-63 |
| ISSN: | 0140-7007 |
| DOI: | 10.1016/j.ijrefrig.2021.01.008 |
| Popis: | In the past decades, combined solar energy with heat pump systems has been one of the very widespread ways to improve the efficiency of conventional heat pumps. In that way, this paper presents an experimental analysis of the influence of environmental conditions in a small size DX-SAHP operating with CO2 as refrigeration fluid to heat water. The variation of the water inlet temperature, the solar radiation flux and the relative humidity are analyzed and 88 different experimental results are presented. To support the analysis, a thermographic camera was also used. The results show that the gas cooler outlet pressure and temperature are strongly influenced by the water inlet temperature. As the water inlet temperature increases, the gas cooler outlet pressure and temperature increase, and consequently the COP decreases. The COP decreases in 45.8% for the variation of the water inlet temperature to 15–35 oC. The variation of the solar radiation of 876.9–30.17 W.m-2 presents a reduction of performance in about 30%. For the same conditions for the water heat exchange, the pressure ratio of the cycle decreases with an augment on the solar radiation flux. In addition, the COP is higher in 6% for a change in the mean relative humidity of 31.6–55.8 %. |
| Databáze: | OpenAIRE |
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