Research on heating and defrosting performance of air source heat pump system based on composite phase change materials

The performance of air source heat pump systems is limited in extreme climate conditions, especially in heating mode, which may face defrosting problems, resulting in energy waste and reduced system efficiency. In order to improve this problem, this article uses 5% expanded graphite/paraffin composite phase change material to preheat the heat accumulator while heating the room, and evaluates the heating and defrosting performance of the air source heat pump based on composite phase change materials. Experimental results show that after using the regenerator, the defrost evaporation period in the defrost cycle is reduced by 42.2%, the resume heating period is reduced by 38.7%, the compressor power consumption is reduced by 42.1% compared with the original system, and the average outlet temperature of indoor unit increased by 8.1?C, and the indoor temperature fluctuation is reduced. This research is of great significance to the performance optimization of air source heat pumps under frost-prone conditions.