Collecting energy from the Earth
By B. H. Bose
With the strong desire by homeowners to lower their heating and
cooling costs, interest in geothermal energy continues to rise,
literally, from the ground up.
That interest, which is prevalent in other parts of the country,
has finally found its way to the South Lake Tahoe area, as two
homeowners have decided to use the earth’s natural energy to heat
and cool their future Fallen Leaf Lake home.
“After reading up on (geothermal energy), it made a lot of sense,”
said Jane Mitchell, co-owner of the home with her husband, Jim.
“If you are out here in the Sierra and really care about the environment,
it is the way to go. It is clean and there’s no propane involved,
which was a big reason.”
Geothermal systems work by collecting the Earth’s natural heat
with a series of closed pipes. While furnaces create heat by burning
fuel, such as propane or natural gas, geothermal (GeoExchange)
systems rely on the heat that is already in the earth, so there
is no need for combustion.
Fluid circulating through the closed pipes, called loops, placed
well beneath the surface, brings the heat back to home, which
is then released throughout the home after going through electrically-driven
compressors and heat exchangers in a vapor compression cycle.
It is reported to be the same principle behind refrigerators –
which keeps contents cool by drawing heat from the interior of
the device and disperses it to the outside air.
The temperature of the ground approximately 5 feet beneath the
surface remains at a constant temperature. That temperature varies
throughout the United States. In the Tahoe Basin, it is about
56 degrees, said Ron Greer of Brower Mechanical of Nevada, Inc.,
installers of the GeoExchange system.
“Almost all power companies are going for this because they are
running out of power and this is one counter measure,” Greer said.
“I don’t know of any drawbacks with it.”
At the Fallen Leaf Lake site, Greer said there will be eight holes,
about 6 inches in diameter, drilled about 180 feet into the ground.
Two pipes, connected at the end in a “U-shaped” formation, are
then lowered into the hole. The pipes, running about 5 feet underground,
lead to two small heating units in the house.
Once there, the heat is concentrated and released at a higher
temperature through the compressors and exchangers. In the summer,
the process is reversed to provide air conditioning. Namely, the
excess heat is extracted from the house, expelled into the loop
and absorbed by the earth.
The GeoExchange system will provide in-floor heating, hot water,
and air conditioning for the 3,000-square foot home and two adjacent
cabins, said Greer. And while it costs more to install, he added,
that the monthly energy bills will be low enough for the project
to be more economical than using other sources of heat such as
the use of propane.
“On average, it is about one-third higher in cost to install than
more common heating systems, perhaps 30 to 40 percent higher than
gas heat,” said Greer, who designs and engineers the systems for
his company. “But the monthly bills are about 50 percent lower.
A heating bill can be as high as $400 a month. With the GeoExchange
system, it can be approximately 50 percent less.”
Other advantages of using this system, according to Mitchell and
Greer, are safety and aesthetics.
“The whole idea is to produce something you can’t hear or see.
It is clean and quiet,” Mitchell said. “Plus, it is getting rid
of the propane. That propane boiler we have now gets really loud.”
“It is the most environmentally-friendly system available,” Greer
added. “It is instead of using fossil fuels and it is safer than
using propane, which can be really dangerous.”
Mitchell also pointed out that she will be pleased with the GeoExchange
system in the winter because it is capable of running off a generator
if the power goes out. Also, since the roads are not plowed in
the winter she won’t have to worry about getting somebody up to
the lake to fill their propane tank if it runs out.
All in all, Greer said there are about 100,000 GeoExchange systems
in use throughout the United States. Most are situated out East,
he said, because of the early energy concerns.
“It has been going on for about 40 years on the East Coast. We
have only been doing this on the West Coast for about five years,”
Greer said referring to his company and the drilling company they
use, Bertram, out of Montana. “California never really got into
this until late, because it was never worried about power. But,
now with that worry around, and environmental issues, and cost
issues, it is becoming more popular.”
Greer said the Mitchell home is the first that he knows of in
the South Lake Tahoe area. Currently, however, he is working on
a number of homes in the Sacramento area, along with 30 homes
in the Truckee region.
While California and Nevada may be far behind the East Coast in
terms of numbers of homes equipped with GeoExchange systems, homeowners
are definitely making up for lost time, Greer said.
“I can’t keep up with it, people are calling all the time,” he
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