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Advanced Heat Recovery System
Team Members: Andrew Kitchen, Benjamin Thompson, David Mousette, Shane Dow
Advisors: James Labrecque, Justin Poland
Engineering & Science Research Building (ESRB)
• ESRB constructed in 2004
The Barrows Hall Engineering and Science Research Building addition was
completed in 2004 and contains 51,000 square feet of laboratory and office space. The
addition uses 54,000 CFM of outside ventilation air for the laboratories. This amount of
ventilation air is necessary to satisfy OSHA regulations. OSHA mandates high ventilation
air rates for laboratory spaces to quickly remove any volatile substances from the lab
environment. Plans for the building called for the installation of a water-glycol heat
recovery system. The air handler units and exhaust ducts were outfitted with spaces for
heat recovery coils, but a system was never installed.
This project proposes the installation of a direct expansion heat pump heat
recovery system. This system will recover heat from the exhaust air and reject it into the
incoming ventilation air. Direct expansion heat pumps take advantage of the latent heat
of vaporization allowing it to outperform a water-glycol system.
Refrigeration Cycle
• Takes advantage of latent heat of vaporization to transport heat
• Evaporator coil reclaims heat from warm exhaust air
• Condenser coil rejects heat to cold make-up air
• $16 million to build
• Laboratory space for engineering research
• Laboratories require 54,000 CFM of ventilation air
• No recirculation, 100% outdoor make-up air
Turbocor TT400 Compressor
• Plans for water-glycol heat recovery system put on hold
• Currently no heat recovery system installed
Economic Analysis
Economic Comparison of Heat Recovery Systems
$6.00
$5.00
Savings (dollars/hr)
$4.00
D-X system
W-G system
$3.00
$2.00
• Variable speed two stage centrifugal compressor
$1.00
• Levitating magnetic bearings do not need lubrication
$0.00
-10
-5
0
5
10
15
20
25
30
35
40
45
• Extremely quiet operation
Outside Air Temperature (F)
• Will outperform a water-glycol system
• Economizer port to increase efficiency
• Average savings of $5.50 per hour
• Capable of very high coefficient of performance (COP)
• Annual savings of $24,000
• Five year investment return
ESRB Mechanical Room
No. 6 Fuel Oil
• Thick tar-like oil
• Cost $0.83 per gallon
• 151,000 BTUs/gallon
• 2% Sulfur
• Use regulated by the EPA
The university’s steam plant is responsible for heating over 80 buildings on campus.
The steam plant burns 64,000 barrels of No. 6 fuel oil per year resulting in 320 million
lbs of steam. At a cost of approximately $35 per barrel this equates to $2.24 million
per year spent on heating. The installation of heat recovery systems on campus could
greatly decrease the university’s heating bill. As a result the money saved could be
used to fund other projects.
As of right now it costs roughly $96,000 a year to heat the ESRB. Without a heat
recovery system a large amount of energy is wasted on a daily basis. With a direct
expansion heat recovery system installed the heating cost could be cut to about
$72,000 per year saving the university $24,000 annually.
Its is important for a heat recovery system to be installed not only to save the
university money, but to also decrease the amount of No. 6 fuel oil burned. On a cold
winter day the University of Maine burns 600 gallons of No.6 fuel oil every hour. When
burning No.6 fuel oil, like all fossil fuels, it produces large amounts of carbon dioxide
(CO2). Carbon dioxide is a green house gas and is one of the largest contributors to
global warming. Another disadvantage of No.6 fuel oil is that it contains 2% sulfur (S)
which, when burned, produces sulfur dioxide (SO2). In the atmosphere sulfur dioxide
can form sulfuric acid which contributes to acid rain.
• Located in attic of ESRB
• Supplies ventilation air for labs
• Steam heating coils heat ventilation air in the winter
• Chiller absorber used for cooling ventilation air in the summer
• Three 30 hp fans ventilate the laboratory space