Some facts about our geothermal home heating you need to know.
What is a geothermal system?
Geothermal energy systems use an inexhautible renewable power source, the Earth. Creating heat from the burning of fossil fuels is expensive whereas to simply move heat to and from the ground is far more cost effective. The Earth's crust acts as a gigantic battery storing the solar energy from the Sun and the planet's core. This constant supply of green energy allows your home to stay warm in the coldest winter and cold in the hottest summer.
There are two components that are required for a geothermal home heating system. The first is the ground source loop which can be vertical, horizontal, well, lake, or pond depending on the location. The second is the ground source heat pump which can be either forced air heating (water to air) or hydronic, in-floor heating (water to water).
The loops are placed within boreholes drilled deep within the Earth or placed horizontally in trenchs. The anti-freeze Within the loops is circulated absorbing the heat within your home then transfering it to the ground during the summer months and absorbing the heat from the ground and transfering it to your home in the winter. This is possible because of the constant temperature of 5 degrees Celcius deep underground or under water. This heat is then moved through your homes ducts or radiant floor pipes by a heat pump.
One geothermal heat pump less than half the size of your furnace uses forced air or water heating to provide you with air conditioning or heat for your radiant floor systen and hot water tank.
Why is the ground loop so important?
Every geothermal energy system is specific to each site. The type of loop required depends upon the amount of space available on your property has along with the ground conditions.
The geothermal ground source loop needs to be installed correctly. This is not the the type of job that is to be left by a new startup company with little experience. If the pipes are installed to close together they will end up competing with each other. The result is that in the winter months the moisture surrounding them crystalizes and air pockets form which results in a loss of thermal conductivity. During the summer months the loop can't dump heat into the surrounding soil as efficiently which causes your heat pump to overwork itself and possibly fail.
With this in mind the general rule is that it's always better to drill rather than trench. Geothermal drilling takes up almost not extra space and because the hole gets down into the bedrock resulting in a higher COP (coefficient of performance). Better conductivity means an easier transfer of heat which equals more energy savings for you.
A vertical loop is required when the size of your land in inappropriate for a horizontal loop. Boreholes are drilled into the ground to a depth of normally 150 to 175 feet deep and a geothermal pipe is inserted. The advantage of a vertical loops system is that it can be used in a smaller area than a horizontal loop sytem.
Horizontal closed loops are loops that are buried at a depth of 6' in 4' wide trenchs. Four of these trenchs will provide all the renewable engergy to heat and cool a typical home.
Lake / Pond Loop
Open loops installed into a lake or pond are a cost effective type of closed loop system. The temperature of the water at the bottom of a lake or pond does not vary more than 5 degrees Celsius from the hottest days of summer to the coldest days of winter. The only requirement is that the depth of the water is enough so the loop is not effected by waves or ice.
Well Loop (Open)
Properties that have a nearby lake, pond, or well that are the appropriate size and depth can have geothermal pipes submerged to the bottom. The is a single trench that is dug from the house to the water source where two pipes are connected to the geothermal piping submerged at the bottom.