Improving Heating Performance of a MPS Heat Pump System with Consideration of Compressor Heating Effects in Heat Exchanger Design

An innovative way of improving heating performance was developed for a 3.5 RT MPS (Multi Power System) heat pump system.In the heat pump system, there were three heat exchangers, one in each front, rear and bottom.The front and rear heat exchangers were supplied with the air from open space when the bottom heat exchanger was supplied with the air heated by the compressor.The result came out as the great temperature difference between the incoming air and the refrigerant in the bottom heat exchanger.The difference was greater than those in the other two heat exchangers.The inlet air temperatures were numerically estimated with a commercial code, and the compressor was modeled as a constant temperature heat source.The temperature distributions were obtained over the three heat exchangers.According to the temperature profile, the refrigerant distribution to the three heat exchangers was redesigned, which means more refrigerant was distributed to the portion of the heat exchanger with greater temperature difference between the air and refrigerant.It directs to improvement of heating capacities by 10% and in addition of 5 % for low temperature heating steady state, and standard rating conditions, ARI 210/240, respectively.The Heating Season Performance Factor, HSPF was improved by 5.2%, without any increase in cost or consuming more energy