Thermoactive geostructures represent an original and efficient technique for fulfilling the energy demand of buildings and infrastructure, in terms of both cooling and heating. Thermal and mechanical aspects have to be considered to achieve a proper design of such structures. This paper focuses only on thermal aspects and deals with the development of an original approach based on the analysis of thermal flux and volumetric thermal power to assess the thermal sustainability of a thermoactive geostructure. This approach is firstly applied to a simple three-dimensional geometry to validate some numerical implementation issues. A case study based on a Grand Paris Express metro station is then presented and analysed in terms of temperature variations and heat exchanges. The consideration of the groundwater flow and the thermal exchanges by conduction and advection provides a new and better insight on the thermoactive geostructure energy assessment. Furthermore, the obtained numerical results show the zones of the geostructures where the heat exchanges are the most significant and where the risk of temperature drift is the highest. This analysis can be used to improve the design of the thermoactive metro station.

中文翻译：

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长期评估热活性地质结构的热可持续性

在冷却和加热方面，热活性地质结构代表了一种满足建筑物和基础设施能源需求的新颖而有效的技术。为了实现这种结构的适当设计，必须考虑热和机械方面。本文仅关注热方面，并基于热通量和体积热功率的分析来评估热活性地质结构的热可持续性的原始方法的发展。该方法首先应用于简单的三维几何，以验证一些数值实现问题。然后介绍了一个基于Grand Paris Express地铁站的案例研究，并根据温度变化和热交换进行了分析。通过传导和对流对地下水流量和热交换的考虑，为热活性地质结构能量评估提供了新的更好的见解。此外，获得的数值结果显示了热交换最重要且温度漂移风险最高的地理结构区域。该分析可用于改进热活性地铁站的设计。