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The Black Point
project involves 130,000 square feet of heating and cooling space,
and will kick out 110 times as much heat as a typical home-heating
system. To do that, the project will use 120 heat pumps and at least
eight wells, each drilled 1,500 feet through the granite ledge of
Prout's Neck to fresh-water aquifers below.
Already, with
32,000 square feet of geothermal heating and cooling in place, the
resort has installed more than a mile of pipe, said Paul Bock, a foreman
on the project for Maine Air Conditioning in Portland, which is doing
the work at Black Point. The company has completed several residential
and commercial geothermal projects in southern Maine during the last
six years.
All of those
geothermal systems rely on two simple facts for their effectivenss
at turning water into heat. Groundwater remains at a relatively stable
temperature throughout the year, thanks to the insulating blanket
of soil and rock around it. And technology makes it possible to pull
heat out of that water, or add warmth into it, to heat and cool buildings.
"It's really a natural solar heating system," said Douglas Martin,
president of Maine Air Conditioning.
The hot core
of the earth also adds heat to any groundwater that resides more than
500 feet beneath the surface.
"The deeper
you go, the warmer the water," said Douglas Martin, president of Maine
Air Conditioning. At 1,500 feet in Maine, water remains in the mid-50
degrees Fahrenheit year-round.
At the Prout's
Neck resort, groundwater is pumped from the wells to the buildings
that will be heated and cooled. The water is filtered and then sent
to each room at the inn.
There, individual
heat pumps perform the magic of turning tepid water into comfortably
warm air. Here's how it works:
During cold
months, heat pumps use a refrigerant to pick up warmth from water,
similar to the way home refrigerators pull heat from the air. The
heat is then blown out into the room by electric fans, just as a refrigerator
blows out warm air.
