How does geothermal energy work? The fundamentals of a ground source geoexchange system are simple. An underground system of HDPE (high density polyethylene) plastic pipes form a ground loop that exchanges thermal energy with the earth to heat your home during the colder months and cool your home during the summer months.
During the heating season the earth is used as the energy source to provide the thermal energy needed to maintain your home at a comfortable indoor temperature. During the summer the same underground system uses the earth as a heat sink (depository) to remove excess heat from the indoor environment and keep the house cool and conditioned.
If you were to measure the temperature of the earth at a depth of 3 metres (about 10 feet) below the surface you would find that temperature to be close to 12* C (55* F) at any time of year. There is no significant change in temperature as we go deeper and therefore no seasonal variation in the amount of available ground energy. The earth that we install the geothermal pipes into remains relatively constant throughout the year. Even in the middle of winter with a thick covering of snow on the ground the earth below can provide enough renewable energy to heat your home.
The HDPE pipes are buried in the ground and filled with a water solution that has a 20% solution of ethanol antifreeze mixed in. As specified by CSA 448 B code requirements, this creates an efficient heat exchange fluid that is circulated through the pipes and delivers energy back to the heat pump(s). This collected energy is concentrated into a useable form by the heat pump through a thermodynamic process similar to a conventional refrigeration cycle.
Each heat pump installed replaces both a furnace and an outdoor AC unit. In larger homes we routinely install several heat pumps and by doing so eliminate the need for a matching number of furnaces and air conditioning units. With a geothermal heating and cooling system there is no equipment outside the house which also means no noise, nothing unsightly to look at and no seasonal equipment to maintain.