Geothermal energy plants use hydrothermal sources that have both water (hydro) and heat (thermal). Geothermal energy plants require high-temperature (300°F to 700°F) hydrothermal resources that come from either dry steam wells or from hot water wells. Individuals use these resources by drilling wells into the earth and then piping steam or hot water to the surface. The hot water or steam is employed to operate a turbine that generates electricity. Some geothermal wells may well be as deep as two miles.
In general, closed loop systems normally circulate an antifreeze option through a closed loop buried in the ground or immersed in water. Heat is transferred in between the refrigerant in the heat pump and the antifreeze answer in the closed loop by means of a heat exchanger. The possible configurations for the loop are horizontal, vertical, and pond/lake. 1 variant, direct exchange, does not use a heat exchanger but instead pumps the refrigerant straight by means of tubing buried in the ground (USDOE 2012).
While geothermal heat is everywhere beneath the Earth’s surface, only about ten % of the land surface location has situations where the water circulates near the surface to be simply captured (UCS 2009). Enhanced geothermal systems allow the capturing of heat even in these dry locations. It also is powerful in capturing heat from areas where the all-natural supply of water generating steam from the hot underground magma deposits has been exhausted.
Geothermal energy from hot dry rocks is recovered by drilling deep into the hot crystalline rocks (normally granites) and forcing water down an injection nicely and by means of fractures forced open by the water pressure in the rocks and back to the surface by means of fractures connecting to other wells drilled nearby. The water gathers heat and becomes superheated as it flows by means of the hot rocks.
There is also the potential to generate geothermal hot dry rocks. Holes at least 3 km deep are drilled into the ground. Some of these holes pump water into the ground, when other holes pump hot water. The heat resource consists of underground hot radiogenic granite rocks, which heat when there is adequate sediment amongst the rock and land surface.