Charting a new energy-efficiency pathway for schools

Like many large buildings, schools suck lots of energy from the grid to keep lights on, halls warm and students comfortable, translating to high bills for school districts. However, a case study using a school in Quebec aims to challenge that status quo.

Researchers from Concordia University studied a school that runs off electricity sourced from geothermal heat pumps that rely on energy from Quebec’s grid, which is almost all hydropower.

They found that schools heated with electricity can use less energy and still keep students warm if they understand and adapt to the energy needs of each building. Researchers analyzed data from existing sensors in the school. Then, they combined it with weather predictions for the next day and other information to reduce power use at peak demand times when energy is most expensive. They tested the system in a few classrooms, where they reduced peak power consumption by up to 100 per cent. Their scenario found the school’s energy bill could be cut by up to 50 per cent if their approach was adopted school-wide because of cost savings from reduced power use during peak times.

“This way, instead of relying on a traditional reactive controller like [an ordinary] thermostat, we can program the school’s [heating, ventilation and air conditioning] system to turn on several hours before the school opens. This approach allows us to let the building gradually warm to the temperature required, as well as to exchange the air supply inside,” explained Concordia engineering PhD candidate, Navid Morovat.

The researchers also studied how implementing a photovoltaic/thermal solar air heating system, in addition to the existing heat pumps, could further cut back on energy demand, while introducing more fresh air into classrooms. The solar system works by drawing fresh air warmed by solar energy into the building's ventilation system. The photovoltaic portion turns sunlight into energy, while the thermal portion produces heat. The study suggests the solar and heat pump systems combined with reducing power use at peak times through data analysis can have multiple benefits for school districts and students.

“... This means that children arrive at a school that is already at the thermal comfort level they need and with air that is fresh. As an extra bonus, the school’s electricity bill is reduced,” added Morovat.

Gradually increasing the heat over several hours, as opposed to cranking it during peak hours, uses less expensive electricity, and reduces a school's bills, said Morovat. His PhD thesis is being supervised by engineering professor Andreas Athienitis, who is also director of the Concordia Centre for Zero Energy Building Studies and chair of the scientific committee of Concordia’s Volt-Age CFREF program.

The case study shows this approach could be replicated in other Quebec schools, most of which use natural gas for heat, a planet-warming fossil fuel. If schools installed heat pumps as their primary heat source and used a smart system like the one tested in their study, it would mean significant emissions reductions for the province, explained Athienitis.

In 2021, the most recent year of Statistics Canada data, Canada’s commercial sector — which includes buildings like offices and schools — accounted for 11 per cent of energy demand and seven per cent of the country’s greenhouse gas emissions.

The research was funded in part by Hydro-Québec and the Natural Sciences Engineering Research Council of Canada. Athienitis, who is the Hydro-Québec Industrial Research Chair at the university, said reducing peak demand is in the interest of the Crown utility. It allows the utility to free up more energy to export.

Energy exports are big business for Quebec. In 2022, the province exported the most electricity of any Canadian province, receiving $1.4 billion in revenue, with Ontario and British Columbia being the runners-up. If peak demand is reduced within the province, explained Athienitis, there is enough energy to export to the United States when its demand is also the highest.

“So that's what Hydro-Québec wants us to do. And that's why they are funding this project, right?... That means they save energy. And they can export more energy to the U.S.,” he explained.

Ultimately, the research project addresses energy efficiency, the comfort of students, and creating a healthy indoor environment, said Athienitis, and will hopefully inspire other schools in the province and across Canada.

“We are talking about a lot of things coming together with great benefits to society.”