Experimental Investigation of Heat Transfer Coefficient of a Refrigerant Mixture in a Fin-And-Tube Evaporator

R407C is an accepted alternative to replace R22 hence its vapor pressure and thermodynamic properties are closer to R22 but it has oil miscibility problem with conventional mineral oil. Previous research reported that it is possible to mix HC blend (54.8% R600a and 45.2% R290a) with R407C and the miscibility issue with mineral oil could be solved. In this present study, the overall heat transfer co-efficient for R22 and M20 refrigerant mixture (HFC407C/HC blend 80%/20% by wt) were experimentally investigated in a fin-and-tube evaporator. The tests were conducted by varying indoor and outdoor air temperatures in a psychrometric test facility as per BIS 1391(1992) standard. It was measured that the overall heat transfer coefficient of R22 varied from 144 to 194 W/m²K and the overall heat transfer coefficient of M20 refrigerant mixture varied from 132 to 174 W/m²K.