Condensation of refrigerants in a multiport tube with rectangular minichannels

•Condensation characteristics in a multiport tube are experimentally quantified.•Condensation HTC of R32 is higher than those of R134a and R1234ze(E).•The effect of hydraulic diameter on HTC in rectangular channels is clarified.•Heat transfer model for rectangular channel is developed considering flow pattern.•Pressured drop correlation for minichannels is proposed considering channel shape.

This study investigated the condensation heat transfer and pressure drop characteristics of refrigerants R134a, R32, R1234ze(E), and R410A in a horizontal multiport tube with rectangular minichannels, in the mass velocity range of 100–400 kg m−2 s−1 and saturation temperature set at 40 and 60 °C. The effect of mass velocity, vapor quality, saturation temperature, refrigerant properties, and hydraulic diameter of rectangular channels on condensation characteristics is clarified. A new correlation is proposed for predicting the frictional pressure drop for condensation flow in minichannels. A heat transfer model for condensation heat transfer in rectangular minichannels is developed considering the flow patterns and effects of vapor shear stress and surface tension. Then, based on this model, a new heat transfer correlation is proposed. The proposed correlations successfully predict the experimental frictional pressure drop and heat transfer coefficients of the test refrigerants in horizontal rectangular minichannels.