Experimental Evaluation of Condensation Heat Transfer Coefficient of R-417a in Horizontal Tubes

Abstract

In this paper, condensation heat transfer coefficients (HTCs) of R-417A in horizontal smooth and micro-fin tubes under different parameters such as refrigerant saturated vapor temperatures (dew point) (40-60°C), cooling water inlet temperature (15 -30°C), cooling water velocity (0.65 -0.85ms -1 ) have been investigated. Predicted HTCs in smooth tube are within ± 20% as compared with literature correlations for R-22 and R-417A respectively. Condensation HTCs decreased by 58% as the condensation temperature increased from 40 to 60°C at constant water temperature of 25°C. Cooling water inlet temperature has the most significant impact on condensation HTCs where condensation HTCs increased from 1.6 to 5.6 (kWm -2 K -1 ) as the cooling water inlet temperature changed from 15 to 30°C at refrigerant saturated vapor temperature of 40°C. It should be pointed out, condensation HTCs decreased by 32.3% and 15.3% using R-417A as compared with R-22 at saturation temperatures of 40°C and 60°C at cooling water inlet temperature of 15°C.