Energy solutions Cooling with outdoor air?
By Paul Lambert and Dan Mellinger | February 26,2013
Paul Lambert and Dan Mellinger
I keep hearing about walk-in refrigerators that use outside air to keep food cool. Is this a real thing? If so, how does it work, and can it save me money? ó OP, Bennington County
Paul: What youíve been hearing about is called an outside-air economizer, which can actually be paired with many existing walk-in coolers. These economizers bring outside air into a walk-in when outdoor temperatures fall below the preset temperature. Using the colder outside air instead of the walk-inís compressor condensing unit can definitely save energy and money. And, while I canít guarantee it will work for your business, itís worth investigating for anyone who relies on a walk-in coolerólike a restaurant, grocery store, or beverage center.
Dan: Vermont temperatures are typically cool enough for these economizers to be used roughly 120 days a year, and the energy savings can be up to $770 per year, depending on things like your cooler size and operating hours. You can actually save even more if you have an evaporator fan motor control installed along with the economizer, because it shuts down fans when the compressor isnít running.
Paul: To install an economizer, a trained contractor will mount air-intake and exhaust equipment, connecting the cooler to the exterior wall along with a control unit and efficient circulation fan(s), which will operate when evaporator fans are off. Manufacturer-approved installers can maintain and repair these systems as well.
Dan: As for whether this will work for you or not, that depends. The volume of a walk-in cooler needs to be at least 1,000 cubic feet (thatís volume, not square footage), and there are other factors to consider as well. As with any upgrade, itís best to talk to a professional first. Start by calling Efficiency Vermont at 888.921.5990, and we can help you find the resources you need. Thanks for a great question.
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About Efficiency Vermont: Efficiency Vermont was created by the Vermont Legislature and the Vermont Public Service Board to help all Vermonters reduce energy costs, strengthen the economy, and protect Vermontís environment. For more information, call 888.921.5990 or visit www.efficiencyvermont.com.
The columnists are business energy experts Paul Lambert and Dan Mellinger. v