相变蓄热型空气源热泵系统的模拟

为提高空气源热泵系统的低温适应性，将相变蓄热技术与空气源热泵结合，实现白天蓄热、夜晚放热的运行模式。本文通过模拟研究了相变蓄热型空气源热泵系统的蓄放热特性和应用多级相变材料对系统的影响。结果表明：系统蓄热量随时间线性增大，380 min时达到18.94 kW·h,平均COP为2.51;系统放热量先随时间线性增大，随后增大速率有所减缓，180 min时达到13.58 kW·h。放热过程进口水温为35℃时，系统经过6次蓄放热循环后达到稳定运行状态，蓄放热效率为99.06%。相比单级PCM,应用三级PCM的系统蓄热时间缩短9.60%,COP提高3.97%,总■效率提高4.84%,其中降低过冷区PCM熔点对提高系统性能起到关键作用。

Numerical Research on Air-source Heat Pump System Combined with Latent Heat Thermal Energy Storage

Latent heat thermal energy storage technology is applied to air-source heat pump systems in cold regions to improve their adaptability. Heat is stored during the day and released at night. A simulation is conducted in this study to further investigate the heat storage and discharge characteristics of the system and the effect of applying multistage PCMs (phase-change materials). The results show that the heat storage capacity varies linearly with the charging time, where 18.94 kW?h is achieved at 380 min, and the average COP is 2.51. The heat discharge capacity first increases linearly and then reaches 13.58 kW?h at 180 min. When the inlet water temperature is 35 °C, the system stabilized after six continuous cycles, and its energy storage efficiency is 99.06%. The charging time of the three-stage PCM is reduced by 9.60%; its COP is increased by 3.97%; its total exergy efficiency is increased by 4.84% compared with those of a single-stage PCM. Reducing the melting point of the PCM in the subcooled zone is key to improving the system performance.