Experimental Study of HFE 7000 Refrigerant Condensation in Horizontal Pipe Minichannels

This article presents the results obtained from our own experimental investigations on heat exchange and pressure drop during the condensation flow of the HFE 7000 refrigerant in pipe minichannels with an internal diameter of d_i = 1.2-2.5 mm. The influence of vapor quality x and the mass flux density G on the two-phase flow pressure drops and heat transfer is presented. The tests were performed for the mass flux density range of G = 110-4700 kg/m²s, saturation inlet temperature of T_s = 36-43 °C and heat flux density of q = 1 ÷ 20 kW/m². The pressure drop characteristics and heat transfer coefficient as a function of the internal diameter of minichannels are illustrated. The results of experimental research on the heat transfer coefficient and two-phase pressure drop are compared with correlations developed by other authors. The best accuracy has a comparison of experimental study with correlation of Rahman-Kariya-Miyara et al. and Mikielewicz et al.