Prediction models for condensation heat transfer inside minichannels

The present paper reviews published experimental work focusing on condensation flow regimes and heat transfer in minichannels. New experimental data are available with high pressure (R410A), medium (R134a) and low pressure (R236ea) refrigerants in minichannels of different cross section geometry and with hydraulic diameters ranging from 0.4 to 3 mm. Because of the influence of flow regimes on heat transfer, a literature review is presented to discuss flow regimes transitions. The available experimental heat transfer coefficients are compared with semi empirical and theoretical models developed for conventional channels and with models specifically created for minichannels. Starting from the results of the comparison between experimental data and models, the paper will discuss and evaluate the opportunity for a new heat transfer model for condensation in minichannels.