A performance comparison of serial and parallel solar-assisted heat pump heating systems in Xi'an, China

Abstract

In this study, a TRNSYS model for a solar-assisted heat pump (SAHP) water heating system for a university bathroom in Xi'an was developed and validated through experimental measurements. Under the typical meteorological conditions in Xi'an, a comparative analysis of the performance of the serial indirect expansion SAHP (IDX-SAHP) system and the parallel IDX-SAHP system during different seasons was conducted using the validated model. The results demonstrated that for annual operation, the parallel IDX-SAHP system showed better performance in the Xi'an district compared to the serial system. Under the same heating load, the average coefficient of performance (COP) of the serial IDX-SAHP system was 3.23 and that of the parallel IDX-SAHP system was 4.34. In particular, during summer and the transition season, the parallel IDX-SAHP system showed large advantages, mainly owing to a larger part of the heating load being provided by the solar collector. However, the serial IDX-SAHP system showed a higher efficiency than that of the parallel IDX-SAHP system during winter conditions.