Just as a refrigerator unit moves heat to keep itself cool, geothermal heat pumps (GHP) move air from the earth to both heat and cool buildings.

Normally, heat moves from higher to lower temperatures. A heat pump is a machine that causes heat to flow in the opposite direction of its natural tendency or uphill in terms of temperature. Thus, it is called a heat pump.

Heat pumps are able to move air efficiently.  In GHP terminology, the difference between the temperature where the heat is absorbed—the source—and the temperature where the heat is being delivered—the sink—is called the lift.  The larger the lift, the harder the pump must work to distribute heat; thus determining the efficiency, and therefore the costs, of the GHP.

The alternative to a GHP is an air-source heat pump.  It must create heat from cold outside air and coldness from hot outside air to maintain a constant temperature. In contrast, the GHP obtains heat from relatively warm soil in the winter and delivers heat to the same relatively cool soil in the summer. 

Please visit http://www.geo4va.vt.edu for more information.

Project:  Geothermal Heat Pumps for Energy-Smart Schools in Virginia

PI: Saifur Rahman

Sponsor: U.S. Department of Energy, and the Virginia Department of Mines, Minerals, and Energy

This project reaches out to K-12 school administrators, facility planners, and teachers throughout Virginia, providing educational information on geothermal heat pump (GHP) systems and enabling them to evaluate the likelihood of a successful GHP project at their schools.  

Over 600 schools nationwide have installed GHP systems for space heating and cooling. GHPs are more energy-efficient than conventional heating and cooling systems, thus leading to lower utility bills. GHPs also have lower maintenance costs than conventional systems.  Although a GHP is more expensive to install than a conventional system, the annual savings for a GHP in energy and maintenance are usually returned within four to seven years.