R22 대체 냉매 및 R134a의 포화증기 온도 변화에 다른 외부 응축 열전달계수에 관한 연구

초록

In this study, external condensation heat transfer coefficients (HTCs) were measured on a horizontal plain tube, low fin tube, and Turbo-C tube at the saturated vapor temperature of 30℃, 39℃, 50℃ for R22, R410A, R407C, R134a with the wall subcooling of 3～8℃. The HTCs of all refrigerants are the highest at 30℃, 39℃ and 50℃ in order. This trend due to its excellent thermodynamic and transport properties of the liquid phase. Beatty and Katz' correlation predicted the HTCs of the R22, R410A, R407C, R134a obtained on a low fin tube within a mean deviation of 20%. Heat transfer enhancement factors for the low fin and Turbo-C tubes were 4.0-5.48 and 3.02-8.10 respectively. Turbo-C tube of 3 dimensional surface geometry had the best performance due to a fast removal of condensate.