How do we use it?
Geoheat can be used for numerous heating or cooling requirements. Ultimately it comes down to desired use, available resource, technology and economics. The figure below shows temperature ranges for a series of industrial heat uses, including green housing.
Heat applications need to occur in the same location as the heat source. Transporting heat long distances is currently uneconomical and can result in heat loses, although can be done in some situations.
Geoheat can be used directly, if the subsurface energy matches the required heat for application, or alternatively, a heatpump or heat exchanger may be used. There are numerous different heat exchangers and heat pumps currently available, which can enhance temperatures of a resource at a site to match desired application. The equipment used to convert heat into usable heat is often the same or very similar to technologies used in other heating and cooling systems. The table below provides some information on available technologies for enhancing temperatures.
* The Resource Management Act (RMA 1991) defines geothermal water as water at temperatures of 30ºC. and above. We have chosen to end the temperature range at 150ºC as anything below this is generally classified as low temperature by the geothermal sector in New Zealand. Higher temperatures are used directly in applications, such as wood processing, food processing and milk drying facilities in Kawerau and Taupō.