Exergy analysis of a frost-free air source heat pump system

The main focus of this paper is to analyze the exergetic characteristics of a frost-free air source heat pump (ASHP) integrated with solid dehumidification and phase change heat storage. The exergy loss, exergy loss ratio and exergy efficiency of the system have been calculated to investigate the influence of the operation modes on the system characteristics. In addition, a comprehensive exergy loss ratio is defined to evaluate the system performance. It is concluded that the comprehensive highest exergy loss ratio is obtained as 51.4 % for compressor, followed by the energy storage device (ESD) with 15.8 %, the extra heat exchanger coated with a solid desiccant (EHECSD) with 10.7 %. Also the variation of the exergy loss, exergy loss ratio and exergy efficiency of the system and the key components with the ambient temperature changes from −20 to 5 °C are discussed. This study can provide guidance for optimizing the structure and improving the frost-free ASHP system in the engineering applications.