Thermo-mechanical performance of a geothermal pile system for re-harvesting the energy loss through the basement of a building in cold regions

Maryam Saaly, Pooneh Maghoul, Hartmut M. Holländer

In the proceedings of: GeoSt. John's 2019: 72nd Canadian Geotechnical Conference

Session: Sustainable Geotechnics

ABSTRACT: Geothermal energy piles are bi-functional structural elements that are used to support the building, as well as to operate as geo-heat exchangers for shallow geothermal energy systems. However, broad application of thermo-active piles is hindered due to the underground thermal imbalance. We used a numerical thermal analysis for the example of an institutional building located in Winnipeg (MB) to assess the thermal balance of the ground. The heat exchanger probes inlet temperature of the geothermal energy foundation was chosen to meet the underground thermal balance. In addition, using Thermo-Mechanical (TM) modeling, the impacts of thermal loads on mechanical performance of the geothermal pile foundation was studied. The results showed that the axial stress effective on the pile increased by 8% due to thermal loads. Therefore, to consider thermo-active piles as an alternative for buildings energy supply, further considerations should be made to keep the axial stress induced by thermal loads within the admissible range.

RÉSUMÉ: Les pieux géothermiques sont des éléments structurels utilisés aussi bien pour soutenir un bâtiment que pour fonctionner comme échangeur géothermique. application de tels pieux est limitée à cause du déséquilibre thermique dans le sol. Une analyse numérique thermique a été effectuée sur un bâtiment situé à Winnipeg thermique du sol. La température d'entrée du fluide de l'échangeur de chaleur dans le pieu géothermique a été retenue comme critère. De plus, en utilisant un modèle Thermo-Mécanique, les effets des chargements thermiques sur la performance mécanique ieu géothermique ont été étudiés. Les résultats ont montré que la contrainte axiale impliquée sur le pieu avait augmenté de 8% en raison des chargements thermiques. Dès lors, afin de considérer les pieux thermoactifs comme une alternative pour fournir énergie des bâtiments, il faut envisager de maintenir la contrainte axiale induite par les chargements thermiques dans un intervalle acceptable.

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Cite this article:
Maryam Saaly; Pooneh Maghoul; Hartmut M. Holländer (2019) Thermo-mechanical performance of a geothermal pile system for re-harvesting the energy loss through the basement of a building in cold regions in GEO2019. Ottawa, Ontario: Canadian Geotechnical Society.

@article{Geo2019Paper328,author = Maryam Saaly; Pooneh Maghoul; Hartmut M. Holländer,title = Thermo-mechanical performance of a geothermal pile system for re-harvesting the energy loss through the basement of a building in cold regions,year = 2019}