GeoExchange is the industry's term used to describe an alternative to traditional oil- gas- or coal-fired heating, ventilation and air conditioning (HVAC) systems. Geoexchange systems have also been referred to as earth energy systems, or geothermal heat pump systems. The idea is to take advantage of the ground's heating and cooling properties (the same properties that make any basement cooler in the summer and warmer in the winter) to heat or cool entire buildings. This heat 'exchange' between the ground and the building is accomplished by using standard pump and compressor technology.
- Geoexchange technology can save the developer or consumer up to 70% on their current heating bills, because it transfers existing heat without combustion,
- Geoexchange often pays for itself in less time than a traditional HVAC system, depending on current building heat/cool use, soil types, size of installation, and other factors.
- Geoexchange qualifies as a renewable energy - a typical two bedroom house-sized installation is equivalent to taking two cars off the road or planting one acre of trees.
- Geoexchange systems involve no combustion, so they are cleaner and safer to handle than either oil or gas.
- Geoexchange takes up much less space than traditional HVAC systems, they are particularly suitable for situations where space is at a premium and/or aesthetics matter.
The sun has always provided heat for the earth. Its energy warms the earth directly, but also indirectly. Its heat evaporates water from the lakes and streams, which eventually falls back to earth and filters into the ground. A few metres of surface soil insulate the earth and ground water below. The warm earth and ground water below the surface provide a free, renewable source of energy for as long as the sun continues to shine. The earth under an average residential lot can easily provide enough free energy to heat and cool the home built on it.
The free energy has only to be moved from the ground into your home. This is done either by pumping water from a well (open loop) or by pumping a heat transfer fluid through a horizontal or vertical circuit of underground piping (closed loop). The fluid, called the heat transfer fluid, absorbs the heat in the ground water or soil and transfers it to the heat pump. The heat absorbed by the fluid from the solar-heated ground is extracted from it by the heat pump, and the now-chilled fluid is circulated through a heat exchanger over and over again to extract more heat from the earth.
If your home is located near a suitable pond or lake, you can use a Geo- Exchange System (GXS) to draw on this excellent source of free energy.
Natural Resources Canada ( NRCan) and the US Environmental Protection Agency state that geoexchange is the most energy-efficient, environmentally clean, and cost-effective space conditioning system available on the market today.
- high-efficiency geoexchange systems are on average 48 percent more efficient than the most efficient gas furnaces and more than 75 percent more efficient than oil furnaces.
- geoexchange systems outperform the most efficient gas technology, gas heat pumps, by an average of 36 percent in the heating mode and 43 percent in the cooling mode. Energy costs with geoexchange typically are 25 to 50 percent less than other HVAC systems.
- Geoexchange lowers electricity demand by nearly 1 kW per ton of capacity.
- Geoexchange systems generate virtually no carbon dioxide emissions because they burn no fossil fuels on site.
- Geoexchange systems have a lower life-cycle cost than conventional systems, even in sub-arctic and arctic regions where the demand for heating is high. Geoexchange systems also have long equipment life (systems are often warranteed for 25 years and the ground pipe often will last over 50 years).
- Geoexchange systems are optimal for commercial buildings as they provide the architect with optimal design flexibility because the roof and landscape are free of chillers, air handlers and other outdoor equipment. In addition, with geoexchange systems, boiler rooms can be eliminated and the size of mechanical rooms can be reduced.
- The systems are so flexible, they are ideal for renovating buildings with historical merit. One successful strategy is to use smaller heat pumps dispersed in closets, basements, and attics to provide space conditioning and ventilation with minimal ducting. Additionally, there are no unsightly condensers on the roof or grounds to distract from the building's historic charm.
- The elimination of outdoor or rooftop equipment means that the geoexchange system is not exposed to temperature extremes, dirt, pollution or vandalism.
- If every school district in North America that needed to replace a heating and cooling system in the next 10 years decided to install geoexchange systems, the total energy savings over that time frame would exceed $11 billion.
- The electricity required to power one million homes for one year would be saved if every North American school that could use geoexchange did so.
- In 2005, more than 650,000 geothermal heat pump units were installed in the U.S. , resulting in annual savings of 5.2 billion kWh, 26 trillion Btus of fossil fuels, reduced electricity demand by 1.7 million kW and the elimination of nearly 4 million tonnes of CO2.
- 650,000 installations are equivalent to taking 840,000 cars off the road, planting 250 million trees, or reducing reliance on imported fuels by 14 million barrels of crude oil per year.