For most buildings in Ontario, the production of heat, whether for space heating or process heating, is highly energy intensive and often one of the leading sources of GHG emissions[1]. The climate change mitigation strategy of heat recovery involves capturing and recycling excess heat to reduce initial energy needs for heat production. Familiar heat recovery technologies include heat pumps and geothermal technology which effectively capture ambient heat from the air or ground and channel it into building heating and cooling. Heat recovery typically involves custom applications that are based on the specific needs of an individual facility and where excess heat is produced in their processes.
Some innovative examples of more custom applications include recovering heat from wastewater in sewers to supply adjacent building space heating or recovering heat from oven exhaust pipes to pre-heat ovens or facility hot water tanks. In both examples, by using the heat that is already produced by a process, the need for energy to produce additional heat is reduced or eliminated resulting in less GHG emissions. As many applications of heat recovery require a more customized approach, assessments and engineering studies may be required to determine if heat recovery is a feasible strategy for a facility. Though off-the-shelf heat recovery technologies are not common for most application, trends are changing with growing market interest and readiness, meaning that more innovative, market-ready applications are becoming available and expected to become available in the near future. The benefits of heat recovery suggest that it is a strategy worth seriously assessing for organizations that already deal with high amounts of waste heat that might be lost through exhaust pipes (e.g., industry, restaurants).
In addition, heat recovery strategies have significant implications for district energy systems. Charging the earth with heating or cooling is a form of thermal energy storage and another key element of regional and site energy system planning. Businesses should consider if district energy sources exist or are accessible in their region for potential integration. District energy systems are a critical enabling factor for many heat recovery projects around the world.
For more information on waste heat recovery technologies and applications, check out the U.S. Office of Energy Efficiency and Renewable Energy’s Waste Heat Recovery Resource Page.
Bottom Line
Heat recovery involves capturing and recycling excess heat to reduce initial energy needs for heat production. This otherwise wasted heat can be incorporated back into facility operations and reduce the need for heat generated by GHG-producing sources. Heat recovery and district energy require a more customized approach; assessments and engineering studies may be required to determine if heat recovery is a feasible strategy for a business facility.
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[1] Government of Canada. 2021. Annex: Homes and Buildings. Accessed August 23, 2022. Click here for URL.