| Title |
Flow Condensation Heat Transfer Coefficients of R22 Alternative Refrigerants in Plain and Microfin Tubes of 6.0mm Inside Diameter |
| Keywords |
Flow condensation ; 흐름응축 ; Heat transfer coefficients ; 열전달계수 ; Microfin tube ; 마이크로 핀관 ; Heat transfer enhancement factor ; 열전달 촉진계수 |
| Abstract |
Flow condensation heat transfer coefficients(HTCs) of R22, R134a, R407C, and R410A were measured on horizontal plain and microfin tubes. The experimental apparatus was composed of three main parts; a refrigerant loop, a water loop and a water/glycol loop. The test section in the refrigerant loop was made of both a plain and a microfin copper tube of 6.0～6.16mm inside diameter and 1.0m length. Refrigerants were cooled by passing cold water through an annulus surrounding the test section. Tests were performed at a fixed refrigerant saturation temperature of 40℃ with mass fluxes of 100, 200, and 300kg/m2s. Test results showed that at similar mass flux the flow condensation HTCs of R134a were similar to those of R22 for both plain and microfin tubes. On the other hand, HTCs of R407C were lower than those of R22 by 4～16% and 16～42% for plain and microfin tubes respectively. And HTCs of R410A were similar to those of R22 for a plain tube but lower than those of R22 by 3～9% for a microfin tube. Heat transfer enhancement factors of a microfin tube were 1.3～1.9. |