How Does A Geothermal
Home Heating System Work?
The basic elements of a
geothermal heat pump (GHP) system include a:
- Ground loop — system of
fluid-filled plastic pipes buried in the shallow ground, or placed in a
body of water, near the building
- Heat pump — removes heat
from the fluid in the pipes, concentrates it, and transfers it to the
building (for cooling, this process is reversed)
- Air delivery system —
conventional ductwork used to distribute heated or cooled air throughout
Simply put, a GHP works much like the
refrigerator in your kitchen, with the addition of a few extra valves that
allow heat-exchange fluid to follow two different paths: one for heating and
one for cooling. The GHP takes heat from a warm area and exchanges the heat
to a cooler area, and vice versa. The beauty of such a system is that it can
be used for both heating and cooling—doing away with the need for separate
furnace and air-conditioning systems—and for free hot water heating during
the summer months.
Geothermal heat pumps use electricity to heat
and cool, just like a conventional heat pump. However, unlike a conventional
heat pump, GHPs use the relatively constant temperature of the shallow Earth
as a source of heat in the winter and as a repository for heat in the
In the winter, the fluid passing through the
underground (or underwater) loops of piping is warmed by the Earth's heat.
The collected heat is extracted and concentrated by the heat pump, and
distributed through the building's ductwork.
To cool the building in the summer, this
process is reversed — the heat pump moves heat from the indoor air into
the underground loops, where it is transferred to the relatively cooler
ground. The heat removed from the indoor air during the summer can also be
used to produce some of your hot water, or to heat swimming pools, instead
of transferring it to the ground.
Types of GHP Systems
Geothermal heat pumps are generally classified as
"closed-loop" or "open-loop" systems based on the type
of ground loop that they use:
- Closed-loop systems.
Closed-loop systems circulate a solution of water and antifreeze through
a series of sealed loops of piping. The loops can be installed in the
ground horizontally or vertically, or they can be placed in a body of
water, such as a pond.
- Open-loop systems.
Open-loop systems circulate water drawn from a ground or surface water
source. Once the heat has been transferred into or out of the water, the
water is returned to a well or surface discharge (instead of being
recirculated through the system). Open-loop
systems are not recommended for residential use.
Heating Water for Buildings and Pools with GHPs
- Buildings. Most
geothermal heat pumps sold today are equipped with a "desuperheater"
to meet up to half of your home or business's hot water needs.
Desuperheaters provide the greatest benefit during the summer, when hot
water is produced using the excess heat removed from the building during
the cooling process. In the winter, desuperheaters can also reduce your
hot water bills by preheating water. Desuperheaters are standard on some
units, optional on others. Stand-alone systems that will heat water on
demand (instead of only when space heating/cooling takes place) can also
- Pools. Pool heating
using a GHP is effective in warm climates, where a great deal of excess
heat is produced during the space cooling season. You will need to
purchase a separate "water-to-water" heat exchanger to heat
|To learn more about GHP's and
how they can drastically lower your home energy consumption visit
Energy consultants Doug Rye and Phillip Rye show you how lower you
home energy usage GUARANTEED.
Heat Pump Systems
by Phillip Rye -