Design considerations for thermal energy storage systems in subarctic climate.

Langevin, Hubert; Giordano, Nicolo; Raymond, Jasmin ORCID: https://orcid.org/0000-0002-7486-9185; Gosselin, Louis et Bourbonnais, Martin . Design considerations for thermal energy storage systems in subarctic climate. In: Canadian Geothermal Students' Day, 21-22 juin 2021, Winnipeg, Canada.

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Résumé

Borehole thermal energy storage system (BTES) is a mature technology to provide heating needs of buildings. It can thus contribute to the transition to sustainable green energies in northern Canada. Its efficiency strongly depends on the design and the subsurface conditions in which it is implemented. This study presents a sensitivity analysis of the main parameters influencing BTES operating in the subsurface near freezing conditions. Numerical simulations were performed in FEFLOW to estimate the average heat pump coefficient of performance (COP) of 68 different scenarios of a BTES with 25 borehole heat exchangers (BHE). An initial scenario was constructed and the COP was averaged during heat extraction periods. Then, 17 parameters were varied at constant steps (10% and 30% of their initial value) and their averaged COP was compared to the base case scenario. Results highlight parameters that need to be accurately estimated and optimized in order to maximize BTES efficiency. Thermal power injection/extraction, surface/volume ratio, BHE spacing, BTES layout compared to local groundwater direction and subsurface thermal properties are the parameters with the highest influence on the operating temperature. BTES initial scenario averages a COP of 2.92 over 4 years of operation. Worst-case scenario shows a mean COP of 2.74, whereas best-case scenario averages a COP of 3.05. This leads to a 13 GJ (+5.3%) energy gain difference between the worst and the best-case scenario over ~5.6 years of operation of heat extraction.

Type de document:	Document issu d'une conférence ou d'un atelier
Mots-clés libres:	thermal energy storage system; geothermal energy; sensitivity analysis; design; cold climate
Centre:	Centre Eau Terre Environnement
Date de dépôt:	13 juin 2022 18:12
Dernière modification:	13 juin 2022 18:12
URI:	https://espace.inrs.ca/id/eprint/12617

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