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Maine’s Largest Businesses and Entities Benefit from Custom Heat Recovery Technology

This is the second blog in a series that will highlight the benefits of Efficiency Maine’s Commercial and Industrial Custom Program incentives. To read the first blog, click here.
Maine commercial and industrial facilities are receiving incentives for heat recovery systems and saving energy in high-value areas like air ventilation and water heating. Efficiency Maine has supported projects ranging from common energy recovery ventilators for fresh air supply in schools and offices to complex waste heat recovery in industrial processes. Anytime conditioned (heated or cooled) air or water leaves a building it represents wasted energy and money. Heat recovery systems help minimize those losses.
Heat recovery is a broad topic with equally broad applications that can help reduce energy use in buildings ranging from residences to commercial spaces and large industrial facilities. Its most common application is air-to-air heat exchangers, or energy recovery ventilators (ERVs), that recover energy from exhaust air to precondition incoming outdoor supply air. Air-to-air heat exchangers are usually about 70% to 80% efficient and ERV systems typically provide a high rate of return with short-term, simple paybacks. Instead of direct air-to-air ERVs, larger facilities might use a glycol loop that circulates a water glycol mixture with a piping loop from exhaust air streams to supply air ventilation as a means of energy recovery (air-to-water and water-to-air).
Another common application for heat recovery is to recover heat rejection off of a refrigeration system. Grocery stores and other facilities with large cooling loads use this application because they inherently reject large amounts of heat in order to maintain their operating conditions. Efficiency Maine was able to help Hannaford install glycol loop-based heat exchanger systems in two of their stores in order to recover heat from the refrigeration system and offset building heating needs. These systems typically involve using a water-to-water heat exchanger to recover heat from the refrigeration system, which can be used either directly in water-to-air heat exchangers to preheat outdoor supply air or to preheat water using another water-to-water heat exchanger.
Industrial facilities often have more complicated energy recovery opportunities usually involving large piping systems and two or more heat exchangers. These projects have proven to be some of the Custom Program’s most successful industrial decarbonization projects and several are currently underway.
Facility managers should consider areas of wasted heat, particularly those that are continuous or high volume to see if those conditioned fluid streams can be reduced or minimized through heat recovery. A key aspect of a successful heat recovery project is having an appropriate heat sink to deliver recovered heat to. An appropriate heat sink will need to operate concurrently to the waste heat stream or source, or a thermal storage method will be needed. Many of Efficiency Maine’s Qualified Partners can design and install heat recovery systems and the Custom Program can provide technical assistance to offset engineering costs for large and more complicated projects. Please also check the Custom Program webpage for available incentives. For simpler ERV projects, the Prescriptive Program has incentives readily available.
Please return to our Blog page to read more about how beneficial electrification and heat recovery technology is helping Maine’s manufacturing facilities curtail their reliance on fossil fuels.
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