Geothermal heating and cooling systems use ground temperatures as an energy source for heating and cooling comfort. Though outdoor temperatures fluctuate throughout the year with seasonal changes, ground temperatures four to six feet below the Earth's surface remain relatively moderate and constant year-round. The geothermal heating and cooling system uses pumps to circulate water from a series of wells through an underground loop piping system.
During the heating cycle, the water circulating through the loop piping system extracts heat from the ground. The geothermal unit compresses the extracted heat to a high temperature and, delivers it to the facility through a heat system. The process is reversed for the cooling cycle. Because the earth is much cooler than the air temperatures on a hot day, the geothermal system removes heat from a business or residence and deposits it into the ground. This results in cooler indoor temperatures. Also, some of the heat that is removed by the geothermal system can be used to heat water.
This highly efficient way of heating and cooling has been installed at some City of Raleigh facilities.
Transit Operations Facility
The Transit Operations Facility located at 4104 Poole Road is under review to achieve LEED® Platinum certification.
The facility utilizes 150 geothermal wells, each 300' deep, used for heating and cooling. This facility is top-of-the-line in design and efficiency - saving significant energy costs while reducing greenhouse gas emissions.
The facility received a Sir Walter Raleigh Award for Community Appearance, a City of Raleigh Environmental Award for Institutional Innovation, and the 2012 American Public Works Association Project of the Year.
Wilders Grove Solid Waste Services Center
Wilders Grove located at 4120 New Bern Avenue is under review to achieve LEED® Platinum certification.
The Solid Waste Services Center has 60 geothermal wells installed. The geothermal heating and cooling system is expected to pay for itself and produce energy savings in just two years. The City estimates energy savings from the unit to be more than 30 percent compared to a conventional heating, ventilating and air conditioning system. Additional savings of 20 percent are expected from hot water heating provided by the system.
Furthermore, the geothermal unit helps the City achieve its goal of reducing its use of fossil fuels by 20 percent over five years.