CO_2용 실외열교환기의 오일 영향에 따른 성능변화에 대한 실험적 연구

Abstract

In order to investigate the effects of PAG oil concentration on heat transfer performance and pressure drop during gas cooling process of CO_2, the experiments on fin-tube heat exchanger of CO_2 heat pump were performed. The experimental apparatus consists of a gas cooler, a heater, a chiller, a mass flow meter, a pump and measurement system. Experiments were conducted in various experimental conditions, which were inlet temperature(110℃), mass flow rates(50, 55, 60, 65, 70 g/s) and PAG oil concentration(0 to 2.6 wt%). Heat transfer rate decreased with the increase of the oil concentration and the decrease of inlet pressure. And pressure drop increased with the increase of the oil concentration and mass flow rate of refrigerant. The COP reduction by deterioration of gas cooler performance with oil concentration was analyzed. When inlet pressure of gas cooler is 100 bar, the COP reduction was estimated by 6% under 1 wt% of oil concentration.