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Experimental Study on the Performance of a $CO_2$ Heat Pump Water Heater  

Lee, Eung-Chan (Graduate School of Mechanical Engineering, Korea University)
Baek, Chang-Hyun (Graduate School of Mechanical Engineering, Korea University)
Kang, Hoon (Division of Mechanical Engineering, Korea University)
Kim, Yong-Chan (Division of Mechanical Engineering, Korea University)
Cho, Hong-Hyun (Department of Mechanical Engineering, Chosun University)
Cho, Sung-Wook (Samsung Electronics Co. ltd.)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.21, no.6, 2009 , pp. 367-372 More about this Journal
Abstract
The performance of a $CO_2$ heat pump water heater was measured with a variation of operating conditions such as refrigerant charge amount, outdoor temperature, compressor frequency, EEV opening, and water mass flow rate. The optimum refrigerant charge amount of the $CO_2$ system was 1800 g. At water mass flow rates of 75, 85, and 95 kg/h, the water heating temperatures were 74, 67, and $62^{\circ}C$ and COPs were 2.6, 2.8, and 3.0, respectively. Besides, the compressor frequency and water mass flow rate were adjusted to maintain the water heating temperature at $60^{\circ}C$ with the decrease of outdoor temperature. As the outdoor temperature decreased by $5^{\circ}C$, the compressor frequency increased beyond 60 Hz and the water mass flow rate decreased by 16.7%.
Keywords
$CO_2$ heat pump water heater; Water heating temperature; Water mass flow rate; Coefficient of Performance(COP);
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