Case Study: Condensate Recovery System
Reduces Water Usage and Discharge
The U.S. General Services Administration's Ralph H. Metcalfe
Federal Building in Chicago saved more than 150,000 gallons of
water in one year through the installation of a condensate recovery
system that collected condensed water from the building's cooling
system. By doing so, the scheme provides the cooling towers with
about 15 percent of their water needs and reduces the amount of
water entering Chicago's combined sanitary and storm water
sewers.
A GSA-commissioned study on water recovery options helped the
agency determine that the most cost-effective option was to install
a condensate recovery system on the Metcalfe building's two large
air handlers. From a cost perspective, having two air handlers on
the same floor was ideal so that only one condensate system was
needed. But, their location on opposite ends of the large building
added additional complexity because the plumbing needed to pass
through other rooms. A separate energy project to upgrade all of the
air handling equipment was completed during this same period. The
air handler improvements reduced the cooling requirement and as
a consequence,
resulted in a
reduction in the
anticipated
amount of water
recovered from
the condensate
system.
Relatively
inexpensive
water in Chicago
makes the
return on
investment for
this type of
project longer.
Condensate holding tank with piping, GSA Metcalfe Federal
Building in Chicago.
Sustainable Materials Management
Federal Green Challenge
Key Topics
Water conservation.
HVAC condensate recovery.
Results
150,000 gallons of water
conserved.
15 percent of cooling tower
water provided by recovered
condensate.
Reduced water going into
Chicago's sewer system.
Facility at a Glance
A 28-story federal building in
Chicago's central business
district.
Houses federal offices, a
conference center and a
food court.
Has an ideal layout for the
implementation of a
condensate recovery system.
Participant since 2011 in the
FGC energy, waste and water
categories.
Nominated for EPA Region 5
FGC Award: Innovation.
CHANGING HOW WE THINK ABOUT OUR RESOURCES FOR A BETTER TOMORROW
United States
EnvlrormiBntsI Protection
Agency
www.epa.gov/smm
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Water Usage and Discharge Reduction
However, city water prices are projected to rise over
the next several years which should favor projects
like this one. Cost savings aside, reducing water
demand and preventing thousands of gallons of
water from flowing into Chicago's combined sewer
system are major environmental enhancements.
GSA has found this project to be a worthwhile
exercise in testing new technology and promoting
sustainabilityto building visitors and other GSA
facilities. Guests touring the system often remark
how interesting it is to see such a simple technology
in action. "For the lay person who doesn't know or
understand HVAC Heating, Ventilation and Air
Conditioning technology well, a condensate
recovery system is an easily understood concept,"
said GSA's Sustainability Program Specialist
Bridget Richardson.
Why is reducing discharge important?
In a typical commercial air conditioning system, warm,
humid air from the building is run over a cold air
handler that cools the air. When this is done,
condensate water like water on a cold glass on a
hot day is created and recovered for reuse. A drip
pan collects this relatively clean water and it is dis-
charged to a sewer. In Chicago, the discharge goes
into a combined storm and sanitary sewer system
where it must go through resource-intensive treatment
prior to discharge into the Chicago Sanitary and Ship
Canal and then the Des Plaines River. However, in
large storm events, the combined sewer system
becomes overloaded and the treatment system is
bypassed, diverting untreated rain water and sewage
into Lake Michigan instead. In a condensate recovery
system, this excess water is instead collected in a
tank and is used in the building's cooling towers,
reducing the load on the sewers and water supply
system.
About the Federal Green Challenge
The Federal Green Challenge, part of EPA's Sustainable Materials
Management Program, is designed to challenge federal agencies
throughout the country to lead by example in reducing the federal
government's environmental impact. It helps agencies meet obligations
under Executive Orders 13514 and 13423.
In 2012, nearly 300 federal agencies, representing more than 500,000
employees participated in the Federal Green Challenge. Their combined
efforts resulted in an estimated cost savings of more than $31 million to
U.S. taxpayers.
Region 5, Land and Chemicals Division, Materials Management Branch
EPA-905-F-14-010
February 2014
For More
Information
GSA's Chicago Metcalfe
Federal Biulding contact:
Bridget Richardson
312-385-3038
bridget.richardson@gsa.gov
Federal Green Challenge:
http://epa.gov/fgc
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