光伏直驱直膨式热泵热水器变转速运行特性实验研究

Experimental Study on Variable Speed Operation Characteristics of Photovoltaic Direct-drive Direct-expansion Heat Pump Water Heater

本文提出了1种基于无保温微通道光伏/吸/集热器(PV/T组件)的直流直驱直膨式热泵热水器系统,PV/T组件的光电通过最大功率跟踪控制器(MPPT)直接驱动热泵系统的直流压缩机,光热由热泵系统的蒸发器吸收提质加热水箱中的热水,实现了太阳能与热泵品位对口的系统集成。为提高系统运行效率及可靠性,设计了压缩机转速随太阳辐射变化而阶梯变化的变转速运行工况,并进行了实验研究。结果显示:系统发电量大于热泵运行电量消耗,可实现离网运行。随太阳辐射强度增加而采用压缩机转速升高的运行方式,可控制PV/T组件温升,其平均电效率、热效率与总效率分别为19.65%,48.8%和68.4%;90 L水从18.8℃加热到52.8℃仅用时210 min,系统平均能量利用效率和性能系数分别为68.4%和6.84。随太阳辐射强度减小而采用压缩机转速降低的运行方式,可维持较高的能量利用效率与系统性能系数,系统平均能量利用效率与性能系数分别为93.8%和5.52。

A direct-current direct-drive direct-expansion heat pump water heater system based on uninsulated micro-channel photovoltaic/absorber/heat collector(PV/T modules)was proposed.The photovoltaic of PV/T modules directly drives the direct-current compressor of the heat pump system through the maximum power tracking controller(MPPT),and the heat absorption of photothermal conversion is absorbed and upgraded by the evaporator of the heat pump system to heat the hot water in the heating water tank,thus realizing the system integration of solar energy and heat pump.To improve the operating efficiency and reliability of the system,the variable speed operation condition of the compressor which changes step by step with the change of solar radiation was designed,with experimental research done.The results show that the power generation of the system is greater than that of the heat pump,and off-grid operation can be realized.The temperature rise of PV/T components can be controlled by the operation mode of compressor speed increasing with the increase of solar radiation intensity,with the average electrical efficiency,thermal efficiency,and total efficiency of 19.65%,48.8%,and 68.4%respectively.It only takes 210 min for 90 L water to heat from 18.8℃to 52.8℃.The average energy utilization efficiency and coefficient of performance of the system are 68.4%and 6.84,respectively.With the decrease of solar radiation intensity,the operation mode of decreasing compressor speed can maintain high energy utilization efficiency and coefficient of performance of the system.The average energy utilization efficiency and coefficient of performance of the system are 93.8%and 5.52 respectively.