Abstract:

The domestic air source heat pump water heater (HPWH) can efficiently produce hot water, and the optimization of the design of the wrap-around condenser coil structure can further improve the system performance. In this paper, the structure of the wrap-around variable-pitch condenser coil was proposed. The coupling model was formed by combining a MATLAB heat pump model with a CFD model of the water tank. The accuracy of the model was verified by experiments after it was simultaneously formed. The influence of wrap-around variable/constant-pitch condenser coil structure on the performance of heat pump water heater during charging and discharging was simulated and studied. The results showed that the average heat transfer coefficient and the COP of the wrap-around variable-pitch condenser coil structure on charging increased by 21.91% and 10.75%, respectively, compared with the wrap-around constant-pitch condenser coil structure. The hot water temperature distribution was more uniform. The average heat transfer coefficient and the COP of the wrap-around variable-pitch condenser coil structure on discharging were slightly higher than that of the wrap-around constant-pitch condenser coil structure The hot water extraction efficiency and heat discharging efficiency were increased by 7.69% and 8.53%, respectively. The temperature quality of the hot water discharged from the water tank was improved. This paper provides the direction and guidance for the optimization design of the wrap-around condenser coil structure.

Key words: heat pump water heater, coupling model, extraction efficiency, variable/constant-pitch coil, charging/discharging

摘要：

家用空气源热泵热水器能够高效制取生活热水，优化其冷凝盘管外绕结构设计，可以进一步提高系统运行性能。本文提出了外绕变间距盘管结构形式，通过建立MATLAB热泵模型与水箱CFD模型，联立形成耦合模拟模型，经实验验证耦合模型的准确性后，模拟研究了外绕等/变间距盘管结构对热泵热水器蓄能与用能性能的影响。结果显示，与外绕等间距盘管结构相比，变间距盘管结构蓄能过程中的平均传热系数、性能系数（COP）分别提高了21.91%、10.75%，热水温度分布更加均匀，用能过程中的平均传热系数和COP比等间距盘管稍高，热水输出率、释能效率分别提高了7.69%、8.53%，水箱输出的热水温度品质得到改善。本文为对冷凝盘管外绕形式的优化设计提供了方向和指导。

关键词: 热泵热水器, 耦合模拟, 热水输出率, 等/变间距盘管, 蓄能/用能