Effect of part load operating conditions of an air conditioner on the number of refrigerant paths and heat transfer performance of a condenser

Abstract

Heat exchangers for heat pump condensers and evaporators are usually designed considering rated load conditions. Residential heat pumps and residential air conditioners operate considerably longer at part load conditions than at rated load conditions. This study investigated the difference between a design considering the part load condition and a design considering the rated load condition in heat exchanger path design. The optimal number of paths for each load condition was selected considering the thermal resistance ratio. Results show that the heat transfer rates of a condenser with the optimal number of paths based on thermal resistance under 84%, 51%, and 33% load conditions were 18.29%, 27.58%, and 42.58% greater than the heat transfer rate of a condenser with the number of paths optimized under rated load conditions, respectively. Considering all load conditions, the optimal number of paths with the maximum average heat transfer rate was derived using the weighting factor of the system performance evaluation criteria. The results demonstrated that the optimal number of paths changed when a part load condition was considered in the heat exchanger design.