Performance evaluation of a novel frost-free air-source heat pump integrated with phase change materials (PCMs) and dehumidification

Air-source heat pump (ASHP) has been widely used in domestic and commercial buildings because of its energy savings, high efficiency and environmental friendliness. However, the heating capacity of an ASHP system is greatly influenced by the frost accumulation on the surface of the outdoor exchanger. To solve this problem, a novel frost-free ASHP system, integrating with Phase Change Materials (PCMs) and dehumidification, has been developed. In this paper, the schematic design of this system is first presented. The effect of the match relationship between the desiccant materials and PCM thermal energy storage on the performance of the novel system is then studied using a dynamic mathematical model. The simulation results showed that the dehumidification efficiency was increased from 31.8 % to 34.7 % with the increase of the solid desiccant mass from 1.9 kg to 3.5 kg when the volume of the PCM was 1000 ml. The system COP was 2.87 when the desiccant was 2.2 kg and the volume of PCM was 1100 ml at a relative humidity of 80 % and ambient temperature of 0 °C. In addition, the water temperature was heated to 55°C in one cycle which decreased the irreversible loss. Lastly, a correlation of the system COP with the amount of the solid desiccant and the PCM was obtained through a multivariate linear regression. The results obtained can facilitate optimal design and dynamic behavior investigation of this system.