RP-1589 -- Effects of Fin Design on Frost and Defrost Thermal Performance of Microchannel Heat Exchangers ✓ Most Recent

This research project experimentally investigated the frost growth on louvered folded fins in outdoor microchannel heat exchangers when used in air-source heat pump systems. This research focused on the effects of surface temperature, fin geometry, fin surface coatings and air psychrometric conditions, such as air humidity and air entering velocity, on the thermal and hydraulic performance of the microchannel heat exchangers under frosting conditions. The overall aim was to provide guidelines about frost behavior of microchannel heat exchangers and to develop correlations that predict frost thickness, air-side face-velocity reduction, and heat transfer coefficients for louvered folded fins. The approach taken was to perform laboratory experiments on small scale coils, in which the fins were cut out from commercially available heat exchangers and assembled in a custom-made test apparatus. The fins in the test apparatus were run in controlled laboratory conditions that replicated the ones of actual heat pump system in winter season. A good estimation of the fin surface temperature was achieved with the methodology developed in this project. See more