판형열교환기에서의 Low GWP 냉매 증발 및 응축 특성 연구

In this study, the characteristics of evaporation and condensation heat transfer and pressure drop of R-1234ze(e) and R-1233zd(e) are studied. Condensation and evaporation experimental setups which measure heat transfer and pressure drop are nstructed and experiments are conducted. The variations of heat transfer rate and pressure drop with refrigerant mass flux, heat flux, and saturation temperature are analyzed and the results are compared with the conventional refrigerants. From the experimental results, it is concluded that the evaporation heat transfer coefficients and pressure drops for R-1234ze(e) are 2-6% lower and 13-16% higher than those of R-134a, respectively. In addition, the effect of saturation temperature on condensation heat transfer of R-1233zd(e) is evaluated. It is found that the condensation heat transfer coefficient for R-1233zd(e) decreases with increasing the saturation temperature.