Potential Performance Enhancement of Dual Heat Pump Systems through Series Operation

In this study, the potential performance enhancement in a dual heat pump system through series operation was investigated by a comparison between the performance for parallel and series operation for a heating supply temperature of . To compare the performance of each configuration fairly, the heat transfer surface area of the heat exchangers was fixed. The inlet temperatures and the flow rates of the heat source and the load were also fixed. In addition, the heat transfer and pressure drop characteristics of the working fluids were considered to achieve a more realistic comparison. The results show that the heating coefficient of performance (COP) of the series configuration is approximately 5% higher than that of the parallel configuration under the simulation conditions considered in the present study.