OPTIMAL MODE SWITCHING ANALYSIS OF SOLAR ENERGY AND AIR SOURCE HYBRID HEAT PUMP

doi:10.19912/j.0254-0096.tynxb.2021-1077

Abstract

Abstract: Solar energy and air source hybrid heat pump has different performance in different modes. How to operate in the best working mode in practical application is very important for improving the comprehensive performance of the system. Therefore, two judgment methods for realizing the optimal mode switching of the system are proposed：1）The composite environmental parameter range table of solar radiation intensity and ambient temperature based on the optimal mode switching;2）Refrigerant mass flow distribution ratio through two evaporators （solar collector/evaporator and air-cooled evaporator）. Based on this, the simulation model of solar/air dual source auxiliary heat pump water heater is established in Engineering Equation Solrer（EES）. Firstly, the system performance under different modes is simulated and compared based on the climate conditions in Songjiang District, Shanghai, and then the feasibility of taking the composite environmental parameter range table and mass flow distribution ratio as the judgment method of system optimal mode switching is analyzed and discussed. The results show that at the same ambient temperature, with the increase of solar radiation intensity, the optimal operation mode of the system will change from solar-air mode to solar mode. In addition, it is feasible to take the refrigerant mass flow distribution ratio flowing through the two evaporators as the criterion for mode switching. For the system, the critical value of the mass flow distribution ratio when the optimal operation mode changes from solar-air mode to solar mode is about 2.02.

Key words: solar energy, heat pump systems, coefficient of performance, mode switching, numerical simulation

摘要： 太阳能和空气源复合热泵在不同模式下具有不同性能,如何在实际应用中以最佳的工作模式运行,对提高系统综合性能至关重要,为此提出2种用于实现系统最优模式切换的判断方法：1）基于最优模式切换的太阳能辐射强度和环境温度的复合环境参数范围表;2）流经2个蒸发器（太阳能集热/蒸发器和风冷蒸发器）的制冷剂质量流量分配比。基于此,在工程方程求解器（EES）中建立太阳能/空气双源辅助热泵热水器的仿真模型。首先,基于上海松江地区的气候条件模拟比较不同模式下的系统性能,再分析和讨论将复合环境参数范围表和质量流量分配比作为系统最优模式切换的判断方法的可行性。结果表明,在相同环境温度下,随着太阳辐射强度的增加,系统最优运行模式将由太阳能-空气模式转变为太阳能模式。此外,将流经2个蒸发器的制冷剂质量流量分配比作为模式切换的准则是可行的,对于本系统其最优运行模式由太阳能-空气模式转变为太阳能模式时的质量流量分配比临界值约为2.02。

关键词: 太阳能, 热泵系统, 性能系数, 模式切换, 数值模拟

CLC Number:

TK519

Li Zuqiang, Huang Xinghua, Liu Maoling. OPTIMAL MODE SWITCHING ANALYSIS OF SOLAR ENERGY AND AIR SOURCE HYBRID HEAT PUMP[J]. Acta Energiae Solaris Sinica, 2023, 44(2): 30-36.

李祖强, 黄兴华, 刘茂玲. 太阳能和空气源复合热泵的最优模式切换分析[J]. 太阳能学报, 2023, 44(2): 30-36.

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