Waste energy recovery is the recovery of energy which would otherwise go to wast
e, but instead is being recovered and reused for other energy purposes.
There are three forms of waste energy:
- Thermal energy – recovery from high and low temperatures.
- Chemical energy – taken from gases, municipal waste or combustibles.
- Mechanical energy – derived from high pressure & motion.
British Columbia is currently researching what methods of waste energy recovery would be most beneficial for the province.
Environmental impacts, associated costs and resource availability are all factors when determining if waste energy recovery offers clean energy potential.
Heat Recovery
Currently thermal energy, or heat recovery, is being researched and utilized throughout the province. Heat recovery is the practice of recovering and reusing the thermal energy we throw away, down our drains, through our exhaust systems and up our chimneys.
As an energy source, heat recovery is currently underutilized and often ignored because of a lack of awareness of its benefits.
Benefits of Heat Recovery
- Potentially a clean, renewable energy saver;
- Often cost effective with an excellent return on investment; once heat recovery apparatus is installed, cost savings are guaranteed for both residential and commercial users;
- offers an environmentally sound option to reuse energy that would have otherwise gone to waste;
- Generally, the technologies required to capture and utilize these waste energies are proven, established and off-the-shelf.
Potential Opportunities for Thermal Energy Recovery
Potential opportunities exist throughout the province in industrial, commercial and residential areas.
Exhaust Air Heat Recovery
Exhaust systems within buildings and homes maintain comfortable air quality and humidity by expelling air to the atmosphere. However, if a heat exchanger were in use in a building, it would be possible to heat or cool incoming fresh air using the outgoing exhaust air normally deposited outside. For homes or smaller offices, a heat recovery ventilator would provide good indoor air quality without sacrificing energy efficiency.
Combustion Heat Recovery
Practical for large, existing boiler plants, combustion heat recovery increases energy efficiency. Older, natural gas boilers lose combustion efficiency up the chimney flue where the temperature is consistently high. Combustion heat recovery extracts heat from the flue gases via an installed heat exchanger, sometimes referred to as a flue gas economizer.
Refrigeration Systems
Energy opportunities are available where large scale refrigeration sites exist, sites such as ice arenas or frozen goods warehouses. As these large scale buildings must be kept cool at all times, the heat they generate is constantly filtered into the atmosphere. Opportunity exists to use this heat for space or water heating.
Wastewater Heat Recovery
The water from our shower, sink and toilet has useable, extractable heat, especially when used with a heat pump to increase water temperature. As well, sewer heat recovery converts heat from greywater within our sanitary drains, using a heat exchanger installed within the sewage drains or a series of pipes around the sewage pipes. Sewage treatment plants offer large scale, low grade heat, extracted by heat pumps to heat nearby buildings or be funnelled into a district heating system.
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