外绕微通道冷凝器空气源热泵热水器仿真与优化

空气源热泵热水器比燃气或电热水器更为节能。本文提出了一种外绕微通道冷凝器,可以减少制冷剂充灌量、提高换热效率、降低成本、提高安全性。建立了热泵热水器的准稳态系统模型,制冷剂侧采用稳态模型,水箱和水侧采用动态模型。通过实验证明了该系统模型可以准确地预测时变的系统功耗、水温,以及系统时均COP。通过仿真分析,发现水箱隔热层可以缩短水的加热时间、并提高系统COP约9.2%。增大冷凝器也可提升系统COP,但几乎不改变水的加热时间。最后提出了微通道冷凝器的三流程优化设计方法。

Modeling and Optimization of Air Source Heat Pump Water Heaters Using Wrap-around Micro-channel Condenser

Heat pump water heaters are more energy efficient than the conventional ones using electricity or gas. A wrap-around micro-channel condenser was proposed to reduce the system charge of refrigerant, improve the heat transfer efficiency, reduce cost of heat pump water heaters, and improve safety. A quasi-steady-state system modeling approach to performance simulation of the air source heat pump water heater using wrap-around micro-channel condenser was developed. The refrigerant components were described by steady-state models, while the water tank was described by a dynamic lumped-parameter model. The model was well validated with the laboratory test data of the dynamically cumulative power consumption, time-variant water temperature rise, and the overall time-average COP of heat pump water heaters. Parametric analysis revealed that the insulation layer of water tank can reduce the heating time and improve the system COP around 9.2%, while a bigger condenser can improve the system COP but has negligible impact on the heating time. At last, pass number of the micro-channel condenser was optimized and three-pass design were recommended for higher performance and less chance of refrigerant maldistribution.