Geothermal Fast Facts
- What’s in a Name? GeoExchange, Geothermal, Ground Source Heat Pump, Water Source, Earth Source, Earth Energy all refer to the same type of renewable heating.
- Geothermal literally means ‘heat from the earth’ and comes from the Greek geo meaning earth and thermos meaning heat. The soil is a living system that contains massive amounts of energy that is constantly being replenished from sunlight and rain that fall upon its surface. Geothermal heating captures this free energy by exchange with a refrigerant fluid that is always colder than the soil.
- Engineering and scientific communities prefer to use the term ‘geoexchange’ or ‘ground source heat pumps’ to explain Geothermal Heating as it can be confused with Geothermal Power, which traditionally refers to high temperature heat originating from deep in the Earth’s Mantle – think geysers!
- Ground source heat pumps are very attractive applications where large amounts of energy are required to heat water and/or buildings such as in swimming pools and recreation centres. Ground source heat pumps are installed at The Christchurch Town Hall, Jellie Park Recreation Centre, Pioneer Pool, Waltham Pool and Belfast Pool.
- Dunedin Airport’s passenger terminal has an environmentally-friendly heating, cooling and ventilation system using groundwater pumped from the Taieri aquifer below the airport as its main source of energy. The groundwater heat pump system delivers a substantial saving in energy consumption, operating costs, and capital costs. Dunedin Airport won the electrical and systems award for its groundwater heat pump system in the 2008 NZ Engineering Excellence Awards.
- Geothermal systems are made up of three essential components; a Captor Field to capture the heat from the ground, a heat exchanger or heat pump to force the transfer of heat and a heating system , (such as in floor heating) to distribute the heat.
- A Ground source or Geothermal heat pump works in much the same way as the heat pumps that power air conditioners and refrigerators. All of these devices work by transporting heat from one area to another using a fluid.
- Ground source or Geothermal heat pumps are especially well matched to in floor heating systems which only require warm temperatures to work well. Using large surfaces such as floors, as opposed to radiators, distributes heat more uniformly and allows for a lower water temperature.
- Lord Kelvin, from England, first described the heat pump in 1853. It was later developed by Peter Ritter von Rittinger in 1855.
- The first recorded geothermal system was a 1912 Swiss patent.
- The ground absorbs 47% of the sun’s energy that reaches planet Earth. This amount of energy represents 500 times more than mankind needs every year.
- Installing a geothermal system in a typical home is equal, in greenhouse gas reduction, to planting an acre of trees, or taking two cars off the road.
- In 2001 worldwide Geothermal Heat Pump installations was 572,949. The USA had the lion’s share with 400,000 installations, followed by Switzerland with 41,667, Canada with 30,000 and Germany with 28,667.
- In 2001 per capita Switzerland had the most installations on the planet but this is shifting as more countries recognise the benefits.
- System components have a long life than traditional forms of heating, estimated to be 25 years. Another ‘Green’ advantage of the systems.
- The US Environmental Protection Agency (EPA) has called ground source heat pumps the most energy-efficient, environmentally clean, and cost-effective space conditioning systems available.
- GNS Science is seeking to establish a Working Group with a view to developing an industry association for geothermal heat pumps in New Zealand. The Working Group has over 15 members from across industry and government sectors, including Next Energy Ltd. Read more here.
