Geothermal Energy
Despite Sticker Shock, Schools Save Cold Cash
by Craig Barner
Some schools are
hoping to get an A in economics with their decision to use a geothermal heating
and cooling system.
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A still-unnamed middle school under construction in south
suburban Matteson, Ill., is expected to save $70,000 annually on heating and cooling
costs when operational because a geothermal system is being installed as part
of the $21 million project.
The estimate is based on a study done in 2004
for the school to house sixth- through eighth-grade students in District 159,
said Vuk Vujovic, director of sustainable design for Waukegan-based Legat Architects
Inc., the designer.
Because energy costs have soared since the study was
done, he said the savings might reach $90,000 annually for the project expected
to be finished in August.
Sticker shock is the downside: The upfront cost
for the Matteson project is $440,000 greater with geothermal than a conventional
HVAC system would be. Payback is expected to be realized in 6.3 years because
of the lower energy costs with geothermal.
"For [a school district],
it's a no-brainer because savings continue to be generated with time," Vujovic
said. "Money used for operations budget could be invested in books, programs
and teachers."
With exceptions, geothermal is still in its infancy
in Midwestern schools, but the technology is expected to become popular because
of the cost savings and other reasons.
Energy costs are a timely concern
in the wake of hurricanes Katrina and Rita, which caused shutdowns of oil refineries
and other generating facilities along the Gulf Coast.
"Illinois consumers
have been told to expect a 50 percent increase in the cost of natural gas this
winter," said Keith Bringe, executive director of the Unity Temple Restoration
Foundation in Oak Park.
The Frank Lloyd Wright-design Unity Temple is getting
geothermal as part of an overall project estimated to cost between $12 million
and $15 million. Wright designed among the first electric forced-air heating systems
ever used, but it failed and was replaced with hot-water radiators, Bringe said.
After the geothermal system is installed, the building will be air conditioned
for the first time since it opened in 1909.
(Though the Unity Temple is
not a traditional school, the facility has a strong educational component because
of its association with the iconoclastic architect who pushed architecture in
new directions. Each year, Unity Temple provides educational programming to more
than 5,000 school-age children.)
Cost savings are a godsend for schools,
especially in a political environment where property taxes or referenda to raise
funds for school construction are not always regarded with favor.
In addition,
sustainable design and construction are riding a wave of popularity in engineering
and design colleges nationwide as witnessed by the popularity of the U.S. Green
Building Council's Leadership in Energy and Environmental Design Green Building
Rating System program. More than 2,100 structures nationwide are under consideration
for LEED certification.
Finally, a school can use a geothermal system to
teach students about conservation, a popular topic in education.
"[A
geothermal system] can be used effectively for what is called project-based learning
in education," Vojovic said. "You can have a science project by having
fun and engaging in an activity vs. just memorizing facts."
Learning
about Geothermal Geothermal uses the earth's constant ambient temperature to
heat buildings in the winter and cool them in the summer.
This is done
with compressor-based heat pumps, a loop with refrigerant and water and air delivery
system, said Lane Brown, president of Fort Wayne-based Loop Group Inc., a geothermal
design consultant that worked on the Matteson project. The heat pumps in the building
circulate the refrigerant-and-water mix via a loop - usually composed of polyethylene
pipe - that is placed in a nearby pond or buried in the earth outside.
In
the winter, when warming is needed inside, the system takes heat from the earth,
transfers it to a refrigerant and distributes it into the structure with a forced-air
system.
Cooling in the summer is achieved by taking heat from the structure,
transferring it to the loop fluid and dissipating it into the ground or pond.
The
system benefits the environment over a conventional HVAC system because natural
gas, a fossil fuel, is not being burned to generate heat.
"We don't
have a boiler, chiller and cooling tower [in a geothermal system]," said
Jack DiEnna, key accounts director in Philadelphia for the Washington, D.C.-based
Geothermal Heat Pump Consortium. "We have the ground, and it is using
the earth's thermal capacity, along with electricity."
Besides the
cost savings, another positive is that geothermal systems typically require less
maintenance than a conventional system. Air filters have to be changed "every
couple months," and compressors in the heat pumps have to be changed every
couple years depending on the unit.
Shawn Briquelet, project manager with
Fond du Lac-based J.F. Ahern Co., a mechanical contractor, worked on the $42 million
Fond du Lac High School project completed in fall 2001 that included a geothermal
system.
"If I were to do another, I would encourage the owner to select
a heat pump that's the best quality," he said. "That can be a source
of a lot of or little maintenance." The issue is important because each classroom
would have its own heat pump.
Another positive is that a geothermal system
consumes less space than conventional HVAC, allowing the extra room to be used
for other purposes.
Only a single 40-ft.-long, 20-ft.-wide mechanical room
was incorporated on Fond du Lac High School, Briquelet said. A school with conventional
HVAC would have used at least twice the space for components.
However,
there are negatives to geothermal, too, in addition to the sticker shock.
The
technology might rub against the inherent conservatism of engineers. Schools often
install a boiler as a backup to play it safe.
"Engineers want to put
a belt and suspenders and bungee cord around it (a geothermal system)," DiEnna
said. "They want to put a geothermal system in and a conventional system
on top of it, so this doubles the cost."
Indeed, a boiler was installed
on Fond du Lac High School as a precaution to ensure sufficient heating, along
with geothermal.
Another negative is the noise that heat pumps can generate,
but the problem is solved when heat pumps systems are properly installed and insulated.
Trades
professionals trained in the installation of butt-fusion, high-density polyethylene
line and the laying of line underground are needed, Briquelet said.
Midwestern
schools are largely virgin ground for geothermal. More than 1,000 schools nationwide
have geothermal systems, but only four in Illinois, eight in Indiana and four
in Wisconsin have a system.
Missouri is the exception and has 60 schools
with geothermal. Indeed, the state is one of the top users - along with Kentucky,
Ohio, Oklahoma and Texas - of geothermal overall, DiEnna said.
Rural-oriented
states are leading geothermal users in part because of practicality. It can be
expensive to run a natural gas line of substantial length to each user, whether
commercial or residential, in a rural area.
The geothermal industry hopes
to increase its share of the market.
"We have 1 percent of the market,
and I am going for 30 percent of the market," DiEnna said.
Earth
and Water Either pond- or ground-based systems can be used in geothermal
heating and cooling.
School projects in Fond du Lac and Matteson, Ill.,
have used the pond approach, and some design issues were important, including
the pond size.
"The temperature parameters are quite narrow when you
are trying to extract heat from the pond," said Lane Brown, president of
Fort Wayne-based Loop Group Inc., the geothermal design consultant on the Matteson
project. The pond is 1.8 acres, and the maximum depth is 15 ft. - "not really
a large pond," Brown said.
About 138,600 ft. of pipe of multiple sizes
was installed. The mechanical room inside the school is connected to a vault pit
outside that divides into two 8-in. manifolds. From these, 3-in. polyethylene
pipe emerges and connects to 2-in. pipe that reaches to 33 grids in the pond.
As
a result, there are 66 supply lines because a line takes the liquid to the grid
and another brings the liquid back, Brown said. During the early construction
phase, the grids are floated into the pond but sink and rest on the pond bottom
after the liquid medium is filled.
The medium is made up of about 23 percent
propylene glycol at Matteson, and the remainder is water. The Matterson system
can extract heat as low as 20 degrees F, but the water temperature is typically
about 39 degrees F in winter at the pond bottom where the grids are.
"We
want the pond to freeze in the winter," Brown added. "The ice adds an
insulation layer, and this allows the pond to go into a stabilizing temperature
gradient."
At Unity Temple in Oak Park, a ground system will be used,
and 26 wells will hold the lines. Each well will be drilled to a depth of about
300 to 400 ft., and the majority will be in the front lawn on Lake Street.
In
early November, a drill rig was brought in to drill a test well, and typically
a day will be needed to drill each well to come.
"I think Mr. Wright
would have approved of this system," said Keith Bringe, executive director
of the Unity Temple Restoration Foundation. "We are serving as an international
model for green retrofitting." Survey: Executives
Say Green
Enhances Student Performance A recent survey
of 665 building owners, developers, architects, engineers, corporate owner-occupants,
consultants and educational institutions on green building issues showed that
a majority of survey respondents say green buildings enhance student performance.
In
addition, the survey found that respondents believe environmentally sustainable
buildings attract and retain teachers and reduce student absenteeism.
New
York-based Turner Construction Co. recently announced the findings as part of
an annual survey it conducts. This year's survey focused on green educational
facilities, both K-12 and higher education.
Educational institutions are
recognizing that green facilities provide an effective learning environment. Large
percentages of executives at organizations involved with green K-12 facilities
rated them more highly than traditional facilities on a range of benefits:
Ability to attract and retain teachers (74 percent).
Reduced student
absenteeism (72 percent).
Improved student performance (71 percent).
Executives
reported that green higher-educational facilities performed much better than traditional
facilities on a range of potential benefits. Most of the executives at organizations
involved with green college and university facilities also reported that the facilities
generated more benefits relevant to higher education:
Ability to
attract and retain faculty (71 percent).
Ability to attract students
(70 percent).
Improved student performance (59 percent).
Ability to secure research funding (59 percent).
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