针对中深层地源热泵系统中的深井换热器,基于有限差分法构建数值模型,对其在动态热负荷条件下的传热特性进行分析。通过建立数值模型,结合青岛地区的实际气象数据和现场实验验证,探讨不同流体速度、地温梯度及地质参数对深井换热器热性能的影响。结果表明,深井换热器的进出口温度随动态热负荷波动,但出口温度更为稳定;流体速度的增大虽能提高热输出,但会导致浅层岩土反向传热损失加剧;高地温梯度可显著提升热输出性能,且深层区域的换热效率优于浅层区域。
Abstract
A numerical model based on the finite difference method is developed for deep borehole heat exchangers used in medium-deep ground source heat pump systems, and the heat transfer characteristics under dynamic thermal load conditions are analyzed. Using this model along with actual meteorological data from Qingdao and validation via field experiments, the effect of fluid velocity, geothermal gradient, and geological parameters on the thermal performance of the deep borehole heat exchanger are investigated. The results indicate that while the inlet and outlet temperatures of the exchanger fluctuate in response to dynamic thermal loads, the outlet temperature exhibits greater stability. Although increasing fluid velocity enhances heat extraction, it also leads to higher heat loss caused by reverse heat transfer in shallow rock and soil layers. Higher geothermal gradients significantly improve heat extraction performance, and heat exchange efficiency is found to be greater in deeper regions compared to shallow zones.
关键词
地热能 /
地源热泵 /
换热器 /
数值模拟 /
动态热负荷 /
单位深度热流量
Key words
geothermal energy /
geothermal heat pumps /
heat exchangers /
numerical simulation /
dynamic thermal load /
heat flux per unit depth
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基金
自然资源部滨海城市地下空间地质安全重点实验室开放课题（BHKF2023Z05）; 德阳市揭榜挂帅重大攻关项目（2022JBZG002）; 国家自然科学基金（52078257）
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