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| A Geothermal
(heat pump) System simplified.
You will be aware
that your refrigerator is warm at the back where the heat is
rejected from inside the fridge itself and into the space of
the home. Essentially the same process occurs when a
Geothermal System heats a building, but on a larger scale. A
heat pump tries to refrigerate the soil surrounding the
building and in doing so extracts enough heat from it, to heat
your home. See simple..............
Residential Geothermal Systems typically use compressors in
the 1 to 4 KW
input range, obviously larger homes will require larger
systems, but multiple units get around this little problem.
Commercial applications can utilize three phase power,
increasing the compressor size significantly to outputs of up
to 100 Kw on a single machine and often multiple systems are
required for the total load.
The vapour compression cycle is used in the majority of heat
pumps, and the use of electric motor drives dominates such
units. The principal components in the basic cycle are shown
below. These comprise of an evaporator and condenser, the
compressor and an expansion valve.
Please see http://www.copeland-corp.com/cp_ac/cp_ac_1_1_1_.htm
Not to be omitted is the working fluid or refrigerant,
which circulates around the system.
Please see http://www.copeland-corp.com/cp_ac/cp_ac_1_1_3_1_.htm
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The fluid is evaporated at low temperature and pressure in the
evaporator, using heat from the heat source. ( in our case the
ground source, heat collector). The vapour is then compressed,
raising its temperature before proceeding to the condenser,
which gives out useful heat by condensing the working fluid at
this higher temperature. The flow of the fluid through the
expansion valve reduces the pressure to that of the level in
the evaporator.
The net heat output at the condenser is effectively the sum of
that taken in at the evaporator ( the ground), and the heat
equivalent of the work of compression put in by the drive.
This leads to an energy "bonus" which sets
the heat pump apart from other heating methods - the heat
delivered is greater than that which could result from fully
effective use of the primary energy alone. Hence efficiencies
of 450% or COP's of 4.5 .
Experimental?
Absolutely not, this technology has been in use since the
early 1950's in North America and here in Europe in countries
such as Sweden, Austria and Germany, where it is considered a
normal way to heat, and cool, a building.
What size?
Any size building can be conditioned for exceptional comfort,
provided the unit and earth loop capacities are
sufficiently sized. Computer software is used to assist in
sizing systems to building loads, determining ground loop
lengths and provide customers with an energy use analysis.
Whatever the load we at "Alternative Heating and Cooling
Ltd.", have a
solution for you.
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