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Aerosol Sealing Laboratory Ductwork: Plugging Inaccessible
Leaks Provides Big Savings
Mark Modera, P.E., Ph.D.,
Carrier Corporation and Lawrence Berkeley National Laboratory
Geoffrey C. Bell, P.E., Lawrence Berkeley
National Laboratory
Sealing ductwork in any building saves energy, improves
air and thermal distribution (comfort and ventilation), and reduces
cross contamination between different zones in the building (e.g.,
smoking vs. non-smoking, bio-aerosols, localized indoor air pollutants).
The aerosol-based technology allows sealing ductwork leaks that
are normally inaccessible. This technology has been successfully
applied to both supply and general exhaust ductwork in laboratories
at Lawrence Berkeley National Laboratory (LBNL). Significant, immediate
energy reductions are realized as the ductwork is sealed throughout
a laboratory in three areas: fan power, heating, and cooling. Space
conditions are more accurately maintained including temperature,
humidity, and room-pressure control while energy use is reduced.
At one LBNL lab building, fan-power energy reductions alone reduced
electricity consumption by over 12 percent. Additional savings will
be achieved once this lab building's air distribution system is
fully rebalanced. Facility retro-commissioning will follow the duct
sealing effort to garner additional savings.
Labs21 Connection:
Aerosol sealing has been applied in residences and light commercial
buildings since 1999. An improved sealant injection method for the
technology makes sealing ductwork in large commercial buildings
cost-effective. The aerosol process seals duct leaks from the inside,
using small sealant particles that are deposited at the leaks without
coating the interior of the duct system. This is accomplished by
pressurizing the duct system with a fog of sealant particles sized
to stay suspended in the air until they try to exit the duct system.
By blocking all of the intentional openings in the duct system (i.e.,
diffusers or grilles), all of the sealant-laden air is forced out
through the leaks. As the duct pressure causes the particles to
accelerate through the leaks, they stick and build upon each other
until the leaks are sealed. A process-control computer constantly
monitors the duct pressure and flow, and calculates and displays
the remaining leakage in real-time. When the sealing is finished,
a complete minute-by-minute record of the process is provided.
Biographies:
Mark Modera has been a Staff Scientist at Lawrence Berkeley
National Laboratory (LBNL) for more than 25 years. For the past
dozen years he has devoted most of his efforts towards investigating
and improving the energy efficiency of duct systems. Mark was the
chairman of ASHRAE Standards Project Committee 152P, which published
a new standard for rating the efficiency of residential thermal
distribution systems in March 2004.
Since 1997, Mark has also been working outside of the laboratory
to commercialize an aerosol-based duct sealing technology that he
invented at LBNL, focusing most recently on the commercial building
sector. He is currently directing engineering for the Carrier-Aeroseal
business unit of Carrier Corporation.
Mark has Bachelor's, Master's and Ph.D. degrees in Mechanical Engineering,
and is a registered professional engineer in California.
Geoffrey C. Bell, a member of the
Labs21 Team, is an Energy Engineer in the Environmental Energy Technology
Division at Lawrence Berkeley National Laboratory (LBNL). He is
credited with a number of publications, including serving as a principal
author of the Design Guide for Energy-Efficient Laboratories. This
publication is intended to assist facility owners, architects, engineers,
designers, facility managers, and utility energy-management specialists
in identifying and applying advanced energy-efficiency features
in laboratory-type environments. Mr. Bell is a Certified State Energy
Auditor in New Mexico and a Registered Professional Engineer in
both New Mexico and California. He has served as an investigator
for the U.S. Department of Energy, a teacher at the University of
New Mexico, and an energy engineer contractor to Sandia Corporation
in addition to various other mechanical engineering consulting positions.
Mr. Bell received his B.S. in Mechanical Engineering from Newark
College of Engineering and a masters of architecture in Environmental
Design from the University of New Mexico.
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