新型蓄热增强型能源桩热力响应试验研究

EXPERIMENTAL STUDY ON THERMAL RESPONSE OF ENERGY PILE WITH ENHANCED HEAT STORAGE

  • 摘要: 能源桩是一种将地源热泵系统与地下结构相结合的应用形式,该研究提出了一种蓄热增强型混凝土管桩。针对砂土中的能源桩热-力响应问题,通过大尺寸室内模型试验系统开展了冬季工况下混凝土管桩的热力响应试验,探究了砂土中管桩的换热性能,同时对比了蓄热增强型混凝土管桩与普通管桩的热-力响应差异。结果表明:螺旋布管的方式能够优化换热路径,减少径向传热不均匀,管桩中心填充相变材料提升了15.4%的换热性能,桩侧1倍桩径范围的土体热影响温度变化仅有0.5 ℃。相变材料与导热翅片的复合增强方式没有进一步提高能源桩的换热性能,但相对无翅片桩身温度变化幅度降低了4.8%,桩侧土温降温幅度降低了24.2%,同时改变了传热路径,对桩身应力产生更大的影响。

     

    Abstract: Energy pile is a form of geothermal energy application that combines a ground source heat pump system with an underground structure. A heat storage reinforced concrete pipe pile was proposed. For the thermal-force response of energy piles in sand, a large-size model test system was built to carry out the thermal-force response test of concrete pipe piles in winter conditions. The heat transfer performance of concrete pipe piles in sand was investigated, and a comparison of thermo-mechanical response was made between the heat storage-enhanced concrete pipe pile and the ordinary pipe pile. The experimental results show that the spiral heat exchange tube can optimize the heat transfer path and reduce the inhomogeneity of radial heat transfer, that the filling of phase change material in the hollow of the pipe pile improves the heat transfer performance by 15.4%, and that the temperature change of thermal influence of the soil in the range of 1 times the diameter of pile side is only 0.5 ℃. The integrated reinforcement of phase change material and heat-conducting fins did not further improve the heat transfer performance of the energy pile, but the temperature change of the pile was reduced by 4.8% compared to the pile without fins, and the soil temperature surrounding the pile was reduced by 24.2%. However, the integrated reinforcement changed the heat transfer path of the pile, which had a great impact on the thermal stress in the pile.

     

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