What Is It?
The heat within the earth's surface can be used to supply heating, hot water, and air conditioning at low operating costs due to the reduced need for external fuel. Geothermal heat pumps use the consistent heat of the earth at relatively shallow depths as a heat source in winter and heat sink in summer to provide space heating and/or air conditioning to buildings. In areas where geology brings more intense heat closer to the surface, including near natural hot springs, the much higher temperature heat source can be used directly to provide hot water for heating systems. A typical building can meet between 40 and 70 percent of its energy needs with a geothermal heat pump. A direct geothermal heating system can provide heat and hot water to single buildings or large clusters of buildings.
City of Boise, Iowa
The Boise City Geothermal Heating District taps hot water wells ranging between 1,000 and 3,000 feet deep to deliver heat and hot water to 50 customers including City Hall, the County Courthouse, and several privately owned buildings and churches. (more information
Town of Pagosa Springs, Colorado
Pagosa Springs, Colorado owns and operates a geothermal heating system that uses hot water from the local springs to provide heat and hot water to 15 customers throughout the downtown area, including the local junior and senior high schools and local churches. At a depth of under 300 feet, the geothermal wells bring up water between 139 and 149 degrees. Water is delivered to customers to circulate through baseboard heating systems and returned through a closed loop system. (more information
Ball State University Geothermal Energy System
In the spring of 2012, Ball State University began to operate the largest ground-source, closed-loop district geothermal energy system in the nation. By the time the system is fully operational, the university will be able to completely shut down their four coal-fired boilers. The system uses geothermal heat pumps using 3,600 boreholes to conduct the heat exchange. The system will be used to heat and cool 47 buildings, resulting in $2 million in annual savings. (more information
Sonoma County Water Agency
The Sonoma County Water Agency has two kinds of geoexchange systems, ground source and pond loop. The ground source heat pump cools/heats an office building, while the pond loop system cools/heats a wastewater treatment plant services building. (more information