| Title |
External Condensation Heat Transfer Coefficients of R22 Alternative Refrigerants and R134a According to the Saturated Vapor Temperature Change on a Smooth Tube |
| Keywords |
Condensation heat transfer ; 응축 열전달 ; Alternative refrigerant ; 대체냉매 ; HTCs ; 열전달계수 ; R22, R410A, R407C, R134a |
| Abstract |
In this study, external condensation heat transfer coefficients(HTCs) were measured on a horizontal smooth tube at the saturated vapor temperature of 30℃, 39℃, and 50℃ for R22, R410A, R407C, and 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 is due to its excellent thermodynamic properties of the liquid phase. The measured data of HTCs were compared with the calculated ones by Nusselt's equation for a smooth tube. Measured HTCs of R22, R134a, R410A are 4.2～7.5% higher than prediction respectively while those of R407C are 15.6 ～28.9% lower than the prediction. |