Deposition, Distribution, and Effects of Frost on a Multi-Row Heat Exchanger Performance

Frost deposition across a typical eight-row deep refrigeration display case heat exchanger was studied under varying conditions of face velocity, refrigerant temperature glide, and absolute humidity. The heat exchanger, which used a single phase refrigerant, hydrofluoroether (HFE), was placed inside a wind tunnel in an environmental chamber. Experimental results include frost deposition photos, air side pressure drop measurements, continuous frost mass measurements, and capacity balances. Surface temperature measurements along the heat exchanger fins and tubes show the driving forces of the frost deposition patterns under different operating conditions and provide a means of more evenly distributing the frost. A new style of heat exchanger using plain fins on microchannel tubes is also shown, which has the ability to greatly reduce the refrigerant charge and air side pressure drop.Air Conditioning and Refrigeration Project 10