周期性冷热负荷下白垩纪红砂岩热扩散时效规律研究

The exploration of shallow geothermal energy under periodic heating and cooling load causes energy enrichment in subsurface. Such phenomenon can affect thermal diffusion of the ground, further reduce the performance of geothermal systems, even worse, disable the function of the systems. Therefore, it is necessary to study of thermal diffusion of the ground materials under periodic heating and cooling load. Aim of this project is to examine thermal diffusion of Cretaceous red sandstone over time from following aspects: mechanism of thermal diffusivity, temperature distribution in subsurface under heating or cooling load and behavior of thermal diffusion of red sandstone over time...This study will be technically implemented through different aspects according to the three proposed issues mentioned above: (1) mechanism of thermal diffusivity of red sandstone will be studied by heat transfer theory, basic physical parameters, structure and material analysis; (2) temperature distribution in subsurface will be examined by the installed temperature sensors and Thermal Response Tests on site; (3) behavior of thermal diffusivity of red sandstone over time will be analyzed both via experimental measurements and numerical modelling. An evaluation model concerning thermal diffusive behavior over time of red sandstone will then be proposed.The findings of this study will be validated by in situ measurements and operation of the practical Ground Source Heat Pump system. Furthermore, the outcomes of this study will provide essential information to sustainably exploration of shallow geothermal energy.

浅层地热能开发中周期性冷热负荷造成地质体能量富集，影响岩土体热扩散效率，导致系统性能的持续下降，甚至功能性失效。因此，展开冷热负荷下岩土介质热扩散的研究，对浅层地热能的可持续性开发尤为重要。本项目拟对白垩纪半成岩状多空隙红砂岩热扩散特性的时效规律进行深入研究，探讨孔隙岩土介质热扩散特性、温度场分布规律、热扩散的时效规律。通过孔隙介质物理特性和传热理论，结合基本物理参数、矿物组成和结构特征分析红砂岩的热扩散特性；并通过现场试验和温度场监测，揭示红砂岩在冷热负荷下温度场的时空分布特征；在此基础上，利用有限元模拟和现场地热响应测试建立红砂岩热扩散时效规律的评价模型，将研究结果与已运行的浅层地热能开发系统和其他已发表的研究成果进行对比验证。研究成果可望为浅层地热能可持续性开发和利用提供关键理论支持。

地源热泵系统运行过程中周期性冷热负荷造成地质体能量富集，影响岩土体热扩散效率，导致系统性能的持续下降，甚至功能性失效。因此，展开冷热负荷下岩土介质热扩散的研究，对浅层 地热能的可持续性开发尤为重要。本项目在次背景了下，依托河南省信阳市高铁站某一地源热泵系统展开了对该系统在热冷建筑荷载周期性的作用下地下温度响应的研究。首先，探讨了孔隙岩土介质热扩散特性，结合基本物理参数、矿物组成和结构特征分析红砂岩的热扩散特性；其次，通过现场试验和温度场监测，揭示红砂岩在冷热负荷下温度场的时空分布特征,并优化了钻孔换热器的运行，能为系统节省也25000人民币的运行费用；最后，利用有限元模拟和现场地热响应测试建立了红砂岩热扩散时效规律的评价模型；将研究结果与已运行的浅层地热能开发系统和其他已发表的研究成果进行对比验证，研究成果丰富了岩体地下传热特性的理论基础，可望为地源热泵系统可持续性及高效应用提供关键理论支持。