During May we will be sharing a few blogs on the role that heat pumps and geothermal can play in helping to reduce greenhouse emissions from the building sector. Buildings account for about 30% of Ontario’s greenhouse gas (GHG) emissions and can be 50% of a community’s emissions (such as in Toronto). Reducing the use of fossil fuels to heat our homes and our water is critical to enabling a carbon diet for Ontario’s buildings and ensuring that Ontario and Canada make progress towards our GHG reduction targets.
You may have heard of geothermal energy and thought it was limited to places like Iceland and Hawaii that have volcanoes. But did you know that geothermal is one of the many climate solutions available here in Ontario? While there may not be enough thermal energy in Ontario to cost-effectively generate electricity, there is more than enough energy in the ground to provide Ontarians with low carbon heating and cooling solutions thanks to the marriage between geothermal and heat pumps. Heat pumps are heat exchange systems that are significantly more efficient than traditional furnaces. The ground’s temperature remains constant about six feet below the surface, even when different seasons cause outside temperatures to fluctuate. This means that during summer, the below-ground temperature is cooler than the air above it and in winter, it is warmer. Ground Source Heat Pumps (GSHP) use that differential in heat to cool and heat our homes and buildings.
There are a couple of different ways this marriage between the heat source and the GSHP can work:
This type of loop is located closer to the ground surface and is cost-effective where land is sufficient such as in rural areas or in schools and university campuses such as Fanshawe College and John Paul II Secondary School in London, Ontario.
Vertical loop systems are more common in urban/suburban areas where there is limited land. Vertical drilling is often more expensive than a horizontal loop so this makes the most financial sense for larger buildings such as multi-unit residential or commercial buildings where the drill holes can serve several different buildings (common loop) thereby reducing costs through the efficiency of scale.
Pond or Lake Loop
Water is excellent for heat transfer and if the site is in cottage country or near a water body, a pond loop may be the best option. This is often a lower-cost option than a vertical loop as it does not require drilling.
Wastewater Heat Recovery
GSHPs can capture the waste heat from sewage waste heat or other waste heat sources to provide heating.
Our next blog will focus on the heat pump part of this low carbon marriage. In the meantime, for more information on the role geothermal can play in helping to reduce our greenhouse gas emissions visit the Geothermal 101 webinar.
By, Gabriella Kalapos, Executive Director, Clean Air Partnership and Juliet Rennick