While the ground loop exchanges the heat between the earth
and your home heat pump, the heat pump transfers heat between the ground loop
and the conditioned spaced of your home.
There are some basic thermodynamic principles which guide this process.
Heat is a form of
energy and will always flow from higher temperature to lower temperature. Temperature is actually a way of
measuring how fast molecules are moving.
A heat pump is
something that uses mechanical energy to pump heat in the opposite direction of
where is wants to go: from cooler
to warmer. The way it can do this
is by changing the pressure of a working fluid (sometimes called a
refrigerant).
A familiar example of a heat pump is our household
refrigerators.
The compressor increases
the pressure of the refrigerant vapor, pushing it through the system and
increasing the vapor’s temperature above that of the surrounding kitchen.
In the condenser coil
the refrigerant vapor will condense to a liquid.
The expansion valve
will cause a sudden drop in refrigerant pressure causing it to vaporize.
In the evaporator coil,
the latent heat of refrigerant vaporization is absorbed from the refrigerator.
A GeoThermal system is also called a Ground Source Heat
Pump.
When your home is in need of heating and cooling, ground
temperatures are closer to room temperature than the outdoor air
temperatures. So, during the
summer cooling season, the ground temperature is cooler than the air and the
ground loop is able to condense the refrigerant at lower temperatures which
means that less compressor power is needed to pressurize the refrigerant
vapor. The bottom line is less
electricity is needed which results in a lower electric bill (compared to a
regular air source heat pump, your typical air conditioner).
Below you will see the air conditioning process for a
GeoThermal system.
Using the same logic, during the winter heating season, the
ground is warmer than the air, and the ground loop is able to evaporate the
refrigerant at higher temperatures, which again means that less compressor
power is needed, since the pressure drop through the expansion valve can be
less and still vaporize the refrigerant.
Below you will see the air conditioning process for a
GeoThermal system.
Back to "How Does GeoThermal Work"