Natural Resources, Mining, Industry and Energy Breton Environmental Award and Award of Excellence
Standing Column Wells for Clé-des-Champs School gbi
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A new concept This technology has been the subject of research at Polytechnique Montreal, which worked with gbi to test its theoretical model and then demonstrate its viability. The main advantage of perma18
CANADIAN CONSULTING ENGINEER
nent column wells is a significant reduction in the total number of wells that need to be constructed in the field, compared to a closed-loop well system. With the use of closed-loop geothermal energy, 22 wells of 150 m in depth would have needed to be drilled at the school. With the permanent column wells, on the other hand, only five pumping wells of 135 m in depth and one injection well were required, reducing the project cost by 40%. Standing column wells are feasible in small spaces where geothermal energy was not previously con-
“A really innovative project that will set a standard for other schools.” – Jury
sidered an option, including the sites for many existing buildings that will need to be decarbonized in the years to come. Also, water resides longer in them and allows users to reduce their electrical power demand during severely cold winters.
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Exploration with a deadline The project began as soon as classes ended. The schoolyard had to be available to students, with its new wells, two months later. Most of the work was condensed into short two-phase periods. Existing mechanical spaces were tight, so the team had to work creatively to September/October 2023
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he Centre de Services Scolaire des Mille-Îles (CSSMI) mandated gbi to replace the heating, ventilation and air-conditioning (HVAC) system at its Clé-desChamps primary school, which involved refitting its mechanical room. Through collaboration with the client, it was decided to install a geothermal heat exchanger with permanent column wells—a first for an institutional building in Québec— to make a major shift in energy consumption, reduce pressure on the local electricity generation and distribution network and combat greenhouse gas (GHG) emissions. The concept is to heat and cool an indoor environment efficiently by directly using groundwater, which exchanges heat through conduction and advection with the hydrogeological environment. The technology can rely on a process called the ‘bleed,’ whereby undisturbed groundwater infiltrates a pumping well through a network of fractures in the rock.
