| Title |
An Experimental Study on the Performance Characteristics of Hot-gas and Liquid Bypass Heat Pump Systems for Capacity Modulation |
| Authors |
안재환(Jae Hwan Ahn) ; 주영주(Youngju Joo) ; 윤원재(Won Jae Yoon) ; 강훈(Hoon Kang) ; 김용찬(Yongchan Kim) |
| DOI |
http://dx.doi.org/10.6110/KJACR.2013.25.3.137 |
| Keywords |
고온가스 바이패스 ; 액체 바이패스 ; 히트펌프 ; 용량가변 Hot-gas bypass ; Liquid bypass ; Heat pump ; Capacity modulation |
| Abstract |
A small air-conditioner or chiller for a constant temperature bath normally uses a constant speed compressor. The constant speed compressor is relatively inexpensive, but it uses on/off control for capacity modulation. The on/off control has several disadvantages, specifically energy loss and large temperature fluctuation. Continuous operation with a bypass system can be an alternative to on/off control, for capacity modulation. In this study, a heat pump system having a hot-gas bypass and a liquid bypass was adopted. The performance of the bypass-type heat pump was measured, by varying the bypass valve opening. The differences of the COP between the hot-gas bypass and the liquid bypass, in the cooling and heating operations, were within 2% and 1%, respectively. The liquid bypass showed a wider range of capacity control in the cooling operation but the hot-gas bypass showed a wider range of capacity control in the heating operation. |