Ground-Source Heat Pump Systems (2)

Tuesday August 27, 2019 from 13:30 to 15:10

Room: 524b

TS-225.4 Efficiency evaluation of borehole heat exchangers in Nunavik, Québec, Canada

Nicolò Giordano, Canada

Post-doc Research Fellow
Centre Eau Terre Environnement
Institut national de la recherche scientifique


Efficiency evaluation of borehole heat exchangers in Nunavik, Québec, Canada

Nicolò Giordano1, Luca Riggi2, Simone Della Valentina2, Alessandro Casasso2, Giuseppe Mandrone3, Jasmin Raymond1.

1Institut national de la recherche scientifique, Québec, Canada; 2Politecnico di Torino, Torino, Italy; 3Dipartimento di Scienze della Terra - Università degli Studi di Torino, Torino, Italy

Remote northern communities of Nunavik rely on fossil fuels for space heating and domestic hot water production. The capital Kuujjuaq is characterized by 8500 heating degree days and discontinuous permafrost. Numerical simulations taking into account latent heat effects due to water-ice phase changes demonstrated that the 10-year performance of small-diameter borehole heat exchangers is as valuable as conventional diameters. Moreover, owing to the cold underground, deeper boreholes perform significantly better than shallow ones. A heat extraction rate of 35 W m‑1 can be sustainably maintained by a 300-m borehole. The financial analysis showed that ground-source heat pumps are a viable alternative to fossil fuels. Absorption heat pump is the most interesting technology, but only district-scale applications could justify high drilling and installation costs of vertical ground heat exchangers. Payback time of 15 years was found at the current costs, but less than 10 years can be achieved at 150 CAD m‑1 drilling cost.

Presentations by Nicolò Giordano

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