Feb 2, 2008 12:53 pm US/Central
Heat Your Home Without A Furnace, Or Heating Bill
(WCCO)
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Geothermal heating and cooling has been around for centuries, but it's just recently become more popular because of rising energy costs.
CBS
Imagine heating your home without
burning fuel in your furnace.
Geothermal
heating and cooling has been around for centuries, but it's just recently
become more popular because of rising energy costs.
When the Minnesota winter stakes its claim, all is
warm and cozy inside the Deering home without natural gas or propane. Their heat comes from the earth.
"With the ground being at a
constant about 50 degrees temperature basically all year round," said Jim
Deering.
Denise and Jim Deering chose geothermal
over a regular furnace when they built this 5800-square-foot house nine years
ago.
"The basement has in-floor heat
and then also the garage has in-floor heat as well. So that's all tied in to
the geothermal unit as well," said Jim.
And with all that you won't even
believe how much it costs them to heat in the winter and cool in the summer.
"Typically in the winter a
monthly bill would maybe be average maybe $120 -- $150 and then summer probably
$25 to $30," said Jim.
They figure if they were using a
conventional system their winter cost would be three times as much. They feel
pretty smart about that.
In order to understand how
geothermal works, we have to understand the second law of thermodynamics.
For demonstration purposes of thermodynamics
use the refrigerator.
What you do is place boiled water inside
the refrigerator. Contrary to logic, the refrigerator doesn't actually inject
cold into the hot water -- it removes heat from it.
That's basically the second law of
thermodynamics. Anything that's hot will eventually get not so hot.
So where does all the heat energy go
from the eggs and the milk and the butter and that hot Jello you put in there
yesterday?
Ever feel the hot air coming out
from underneath your fridge? In part, that heat is being extracted from all of
the food inside your refrigerator and being exhausted into the ground.
"It's just a cycle where the
geothermal heat pump is extracting heat out of the ground," said Jim
Cusack, of Bergerson-Caswell, who installs geothermal systems in homes and
businesses.
Right now the company is drilling
geothermal holes for a prison being built in Wabasha.
The holes go down about 180 feet
where the sun has kept the ground temperature at a constant 47 degrees.
David Henrich, also from Bergerson-Caswell,
explains how looping pipes like these go down into the holes with a fluid
inside.
"You're going to have two pipes
coming into your house -- one supply and one return. You're going to hook that
up to your heat pump. Your heat pump is then going to pump a colder fluid down
the supply side of your piping. That colder fluid is going down through these
loops and they're going to be warmed up by the heat of the earth," said Henrich.
So no matter how cold the Minnesota ground is in
winter, the return pipe is going to come back from below the freeze line with a
warmer fluid. Which takes us back to the refrigerator and the fact you can
extract that heat.
"The fluid comes into the geothermal
heat pump at about 47-degrees. The compressor pulls about 5 degrees of heat off
of the fluid. It compresses that heat which then serves to heat the house
either with a forced air system or through a radiant floor," said Cusack.
That compressor can raise those 5
degrees to as high as 165 degrees.
"This isn't rocket science.
This is simple. It's just heat transfer. It's plastic pipe running a fluid down
a hole and you circulate it and it comes out. It's very simple," said Henrich.
The geothermal system does use
electricity, and the Deerings have a separate meter to measure how much the
heat pump actually uses.
Compared with furnaces that burn
fossil fuel, geothermal produces far less CO2, but you don't have to be a
believer in global warming, to be a believer in geothermal.
"We really went after it as
this is just simple and this is going to save us money. And now looking at it
... it's kind of a green effort or a green step for us," said Denise
Deering. "It's an extra plus that we get that too."
This is where I got a headache.
That heat can be extracted from
substances even as cold as 450-degrees below zero.
On the low end, a geothermal system
will add about $50 to a monthly mortgage payment, but you'll save as much as $100
on your energy bill per month. So you'll be $50 dollars, according to the
people who install geothermal systems.
As for the Deerings, their unit has
already paid for itself.
(© MMIX, CBS Broadcasting Inc. All Rights Reserved.)
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