Underground thermal energy storage in subarctic climates: A feasibility study conducted in Kuujjuaq (QC, Canada)

Underground thermal energy storage can provide space and water heating and has been used in temperate climates so far. A step forward is to evaluate the efficiency and viability in arctic to subarctic environments, where rather low ground and air temperatures can make the design of such systems difficult. The present contribution describes the design of an underground storage system in Kuujjuaq (Québec, Canada) to heat the drinking water distributed in the town. The system was designed and modeled with TRNSYS and a parametric study was carried out to improve its efficiency based on 5-year simulations. The 20% of the 425 MWh annual demand can be satisfied by a solar collector area of 500 m2 coupled to a 10,000 m3 underground storage through two short term tanks. Further improvements could be adopted to reach the target of 50% energy from the underground store