|How Geothermal Energy Systems Works
Your own backyard has the potential
to be your source of heating and cooling comfort. Now you can get
safe, reliable, energy efficient heating and cooling from one piece
of equipment. Geothermal energy moves heat energy to and from the
earth to heat and cool your indoor environment. And compared to
ordinary systems, geothermal technology can save you 30% to 60%
on your monthly energy bills. Geothermal is the safest, cleanest,
most reliable space conditioning system you can buy.
Geothermal energy is an unlimited resource. The lot surrounding
a suburban home or other building contains a vast reservoir of low
temperature thermal energy, typically 10 times that required over
an entire heating season. This resource is constantly resupplied
by the sun, the surrounding earth, and heat rejected while cooling
during the summer. The universal definition of geothermal is "...pertaining
to the heat of the earth." By using the earth to provide up
to 50% of a building's total heating and cooling needs, GHP systems
are truly geothermal energy made practical.
Energy in the ground is actually stored energy from the sun. At
six feet below the surface, the earth's temperature is a constant
10-15°C (40-60°F) all year round. This latent energy is
a steady heat source, even in the coldest winter.
|How it is Used
"We are moving energy not creating energy,
so in any terms, geothermal heating and cooling is the most environmentally
friendly and most efficient system, no matter how you look at it.
Eer of 26 and cop of 5/6..."
The Heating Cycle
1. Antifreeze solution is brought back to the heat pump inside
the building via pumps, from the ground.
2. Heat is transferred to the refrigerant in the primary
coil, which boils to become a low temp vapour.
3. The antifreeze is then pumped back into the earth, and
4. Reversing valve now directs the refrigerant vapor to the
compressor. The vapor is then compressed, which reduces its
volume and causes it to heat up.
5. Reversing valve directs the now hot gas to the condensing
coil, where it gives up its heat to the air that is blowing
across the coil.
6. Having given up the heat, the refrigerant now passes through
the expansion device, where it’s temperature and pressures
are dropped before it returns to heat exchanger.
1. A de sup heater or a heat exchanger exists in the heat
2. This takes heat from the hot refrigerant, which has boiled
from the ground temperature coming up, after it leaves the
3. Water from the building is pumped through the coil ahead
of the condenser coil, to allow for some of the heat that
would have been dissipated at the condenser, to be used to
heat the water.
4. This works particularly well in the summer months, as
we are extracting large amounts of heat through the coil,
and in the winter months when the heat pumps balance point
is not working at full capacity. I.e.. The temperatures are
mild, not lower than 5 degrees centigrade.
5. This is ideal for South African conditions.
The cooling cycle
1. This is the reverse of the heating cycle.
2. The direction of the flow is reversed by the reversing
valve in the heat pump.
3. The refrigerant picks up the heat from the building, and
transfers the heat to the antifreeze.
4. The heat is then pumped underground as a heat sink.
5. The earth will naturally accept any quantity of heat at
any given time.
6. Because the refrigerant is rapidly cooled by the extraction
of heat, the coldness is then transferred with the constant
temperature coming back, to the coil and released via blowing
over the coil, which then gives you your air conditioning