Evaporation heat transfer and pressure drop of R161 in a 7 mm micro-fin tube

The evaporation characteristics of refrigerant fluoroethane (R161) in a horizontal micro-fin tube with an outside diameter of 7 mm were investigated by experiment. The heat transfer coefficient and the pressure drop were measured when the heat flux ranged from 28.15 to 49.29 kW/m2, the mass flux ranged from 100 to 250 kg/m2 s, and the saturation temperatures ranged from −5 to 8 °C. According to the results, the heat transfer coefficient went up with the mass flux and the heat flux, and dropped with the saturation temperatures within the experimental conditions. The pressure drop grew with the mass flux and decreased with the saturation temperatures. By comparison, the heat transfer coefficient of R161 was about 23% higher than that of R22. In addition, the ratio of pressure drop (R22/R161) ranged from 0.88 to 1.65. The presented research is helpful in designing more compact and effective heat transfer exchangers for the air-conditioning systems using R161.