HVAC Innovations: Duct Sealing From the Inside

duct-sealing-from-inside

Editor’s note: This article first appeared in the January/February 2016 edition of Business Energy.

According to EPA, the US Department of Energy (DOE), ASHRAE, and various industry reports, having leaky air ducts is one of the leading causes of energy waste in US buildings, says Neal Walsh, Aeroseal’s senior vice president of strategy and commercial sales.

In an example of HVAC innovations, a 23-story high rise apartment building in New Jersey derived $34,000 in annual energy savings after property managers utilized the duct-sealing Aeroseal technology in exhaust shafts and replaced dampers. The facility also is saving several thousands of dollars more each year through increased heating efficiencies.

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On average, US building duct systems lose 30% of heated or cooled air through these leaks. Leaks not only prevent treated air from reaching its intended destination but, when related to ventilation systems, they substantially increase energy usage when fans are turned up to compensate for inefficient building exhaust.

Dr. Mark Modera, a former US DOE researcher and developer of Aeroseal technology, says 80% of US buildings have ducts that leak 20–40% or more, resulting in building code violations, indoor air quality health risks, and wasted energy.

Aeroseal, developed at Lawrence Berkeley National Laboratory in concert with the US DOE, EPA, and local utility companies’ sponsorship, is “a computerized process of applying an aerosol mist of sealant to the inside of the ducts where it locates and seals all the leaks,” says Walsh.

The product is designed to meet tight standards for duct leakage in new building construction and repair leaks in ducts and ventilation shafts of existing buildings, he adds.

Aeroseal is designed to be 95% effective, with studies finding it to be as much as 60% more effective than manual sealing, and labor and repair costs reduced by 30%, says Walsh.

Aeroseal equipment is typically attached to ductwork via a long flexible tube that extends from the equipment to the ducts. “In buildings, the duct connection is usually made at points found on the rooftop—as with ventilation shafts—or via a temporary hole made in the side of the duct itself,” says Walsh.

During the setup process, all of the vents serviced by the ductwork are temporarily closed so that any air being pushed into the ducts can only escape through leaks. The Aeroseal service technician uses computerized equipment to measure the exact amount of leakage before the sealing process begins.

When ready, the equipment is then used to send an aerosol mist of microscopic sealing particles into the interior of the ductwork. The computer monitor provides details of the leakage rate as holes are being filled. At the end of each sealing event, users can generate a computerized report providing accurate account of the pre- and post-seal leakage rate, says Walsh. BE_bug_web

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