土体热物性对能量桩换热效率特性的影响研究

Heat Transfer Efficiency of Energy Pile Influenced by Thermal Properties of Soil

能量桩是一种新型桩埋管形式的地源热泵技术,并在国内外典型工程中获得一定的尝试应用。结合能量桩热响应现场测试数据,基于数值模拟方法,建立考虑不同运行模式下能量桩换热效率分析的有限元数值模型。通过与现场实测数据的对比分析验证了数值模型的准确性和可靠性;探讨土体的热容、土的热传导系数、桩的热容、桩的热传导系数等参数对能量桩换热效率的影响规律。研究结果表明,土体的热容变化对换热效率的影响要大于桩的热容变化的影响,土的热传导系数变化对换热效率的影响要小于桩的热传导系数的变化的影响;土体的热容越小、热传导系数越大,能量桩对桩周土的影响范围则越大。

Energy pile is one of new types of ground-source heat pump technologies,and has been applied in typical engineering in the world.Based on the numerical simulation method,a finite element numerical model is established to consider the analysis of energy pile heat exchange efficiency in different operating modes.The accuracy and reliability of the numerical model established are verified by comparison and analysis of the field data,and the influence law of the thermal capacity of soil body,thermal conduction coefficient of soil,thermal conductivity of pile,thermal conduction coefficient of pile on the thermal exchange efficiency of energy pile is further discussed and analyzed.The results show that the influence of the thermal capacity change of soil body on the heat exchange efficiency is greater than that of the heat transfer change of the pile,the influence of the thermal conduction coefficient change of soil on the heat transfer efficiency of the pile is less than that of the change of the heat transfer coefficient of the pile,the smaller the thermal capacity of the soil body,the greater the thermal conduction coefficient,and the greater the influence of the energy pile on the surrounding soil of the pile.