We often hear about photovoltaic solar collectors. They’re the best-known and most widespread solar technology for producing electricity from sunlight. But there’s another, lesser-known type of solar collector: thermal collectors.
They are used to heat or preheat air or water, which reduces the energy consumption of heating systems and, in turn, their greenhouse gas (GHG) emissions. This solution harnesses solar radiation, an unlimited, renewable and completely free energy source.
How do solar thermal collectors work?
To preheat air, a “solar wall” is used. Its surface absorbs heat from the sun and transfers it through the solar wall into the building’s load-bearing wall. Fans then draw in the warm air and circulate it throughout the building.
For water, slanted solar collectors are used to warm a heat transfer fluid, which is then pumped to a tank to preheat the water inside.
How a solar wall works to preheat air
Good to know
Montréal gets 1,580 hours of sunlight a year, compared to 1,251 hours for Paris and 1,131 hours for Berlin1, the capital of a solar energy leader. That means there’s real potential for developing this resource in Quebec!
The effectiveness of solar thermal collectors depends more on the level of sunlight and the panels’ orientation than on the temperature. In other words, the more sunshine there is, the more efficient they are, whether it’s hot or cold.
Heating vs. preheating: What’s the difference?
Heating a building entirely with solar energy involves installing a complex system to capture, store and distribute heat continuously. However, preheating air or water requires a relatively simple and more affordable infrastructure. Preheating is an efficient solution that can significantly reduce backup energy needs by only covering the last few degrees.
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Find out how harnessing solar energy makes a difference
See how many of our customers have used solar energy to save significantly on energy while reducing their carbon footprint.
“Thanks to the solar wall and the other energy efficiency measures we’ve implemented, we don’t need to heat until the temperature hits -2°C. It’s a big improvement that has a real impact on our employees’ well-being and our energy bills.”
Alcoa’s Deschambault aluminum smelter
Using a solar wall covering more than 700 m2 to preheat its facilities, the plant reduced natural gas consumption by 650,000 m3.
“Having the solar heating panels working reduces not only our energy costs but also our environmental footprint. This kind of grant really allows us to look ahead and plan ways to improve our services”
Accueil Bonneau
The rehabilitation of the Accueil Bonneau solar thermal system saves more than 2,500 m3 of natural gas per year.
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- Source : Certain conditions apply. Grants subject to change without notice. Check grant’s webpage for eligibility criteria.
