Effects of saturation temperature variation due to pressure drop of working fluid in heat exchanger on heat transfer performance

The effect of the saturation temperature drop on the heat transfer performance of a heat exchanger was analyzed under air-conditioner condensing condition, air-conditioner evaporating condition, and refrigerator evaporating condition. The thermodynamic analysis results show that the heat transfer capacity due to the pressure drop of the saturated refrigerant was at least 2.3 % and at most 91.1 % compared to the evaluated heat transfer capacity assuming no pressure loss. The rate of change of heat transfer capacity was the largest in the order of R600a, R1234yf, R134a, R410A, and R32. Heat exchanger performance simulation under practical air-conditioner operating conditions showed that the heat transfer capacity was reduced by 0.72 % due to refrigerant pressure drop under the condensing condition. On the other hand, the heat transfer capacity was increased by 26.55 % under the evaporating condition.