An Experimental Study on the Performance of a Simultaneous Heating and Cooling Heat Pump in the Cooling-only and Cooling-main Operation Mode with the Variation of the Indoor Air Temperature

동시냉난방 열펌프 시스템의 냉방전용 및 냉방주체 운전모드에서의 실내기온 변화에 따른 성능특성에 관한 실험적 연구

The cooling load in winter season is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Therefore, the development of a multi-heat pump which can cover heating and cooling simultaneously for each indoor unit is required. In this study, the characteristics and performance of a simultaneous heating and cooling heat pump in the cooling-only and cooling-main operating mode was investigated experimentally with a variation of indoor air dry bulb temperature which is from $21^{\circ}C$ to $35^{\circ}C$. EEV opening was adjusted from 20% to 24% during the tests. When the indoor air temperature varied, the performance in the cooling-only mode was more sensitive to the temperature than in the cooling-main mode. The total capacity and COP were increased by 53.8% and 48.1%, respectively, in the cooling-main, while those were increased by 19.6% and 19.3% in the cooling-only mode. The performance differences between the two operating modes became larger at lower temperatures, especially for the COP.