Abstract Borehole heat exchanger (BHE) is a promising method for extracting heat from the deep geothermal energy which has been widely used for residential heating in high latitude areas. The solar assisted photovoltaic/thermal (PV/T) heat pump could convert solar energy into useful heat efficiently, and could be further used to heat water from the BHE to a higher temperature level. In this paper, a residential heating system using BHE coupled with solar assisted PV/T heat pump is therefore proposed with further performance analysis. The simulation results show that a larger mass flow rate could increase the BHE's heat extract capacity but also increase the flow resistance and pump power under nominal conditions. The circulating water would not extract heat from rock-soil if the inlet temperature exceeds 48.5 °C when mass flow rate is 12 kg/s. Furthermore, the maximum water temperature from this hybrid system could reach 40.8 °C while the solar fraction is 67.5% when the area of PV/T module is 1000 m2, solar irradiation is 600 W/m2 and depth of the BHE is 2500 m. In the meantime, the heating COP of this hybrid system could reach 7.4 and the system could operate independently without power input from electrical grid.

中文翻译：

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使用埋管换热器结合太阳能辅助 PV/T 热泵的住宅供暖系统性能分析

摘要 钻孔换热器（BHE）是一种从深部地热中提取热量的有前途的方法，已广泛用于高纬度地区的住宅供暖。太阳能辅助光伏/热能 (PV/T) 热泵可以有效地将太阳能转化为有用的热量，并可以进一步用于将 BHE 中的水加热到更高的温度水平。因此，本文提出了一种使用 BHE 与太阳能辅助 PV/T 热泵相结合的住宅供暖系统，并进行了进一步的性能分析。仿真结果表明，较大的质量流量可以增加 BHE 的热提取能力，但也会增加标称条件下的流动阻力和泵功率。当质量流量为 12 kg/s 时，如果入口温度超过 48.5 °C，循环水将不会从岩土中提取热量。此外，当 PV/T 组件面积为 1000 m2、太阳辐射为 600 W/m2 和 BHE 深度为 2500 m 时，该混合系统的最高水温可达到 40.8 °C，而太阳能比例为 67.5%。同时，该混合系统的加热COP可达7.4，系统可独立运行，无需电网输入电源。