New fuel system good for Edwards, environment Published April 20, 2016 By Christopher Ball 412th Test Wing Public Affairs Edwards Air Force Base, Calif. -- The new Bulk Fuel Storage Facility at Edwards is more than just an improvement in fuel delivery efficiency, it is the first facility on Edwards Air Force Base to use a geothermal climate control system. Traditional air conditioning systems use fans and compressors to move air through a heat exchanger. This requires an external heat or cooling source, usually natural gas for heat, and a liquid refrigerant for cooling. While these systems are the most common form of climate control in homes, they are not the most energy efficient. According to the U.S. Department of Energy's website, www.energy.gov, ground temperatures just a few feet under the surface can range from 45°F to 75°F depending on latitude. Like a cave, this ground temperature is warmer than the air above it during the winter and cooler than the air in the summer. The Geothermal Heat Pump takes advantage of this by exchanging heat with the earth through a ground heat exchanger. Geothermal heat pumps, sometimes referred to as GeoExchange, earth-coupled, ground-source, or water-source heat pumps, have been in use since the late 1940s. They use the constant temperature of the earth as the exchange medium instead of the outside air temperature. This allows the system to reach fairly high efficiencies (300 percent to 600 percent) on the coldest winter nights, compared to 175 percent to 250 percent for air-source heat pumps on cool days. According to Joseph Hunt, 412th Engineering Civil Group project manager for the new bulk fuel storage area, the air conditioning is needed for the new bulk fuel storage operations office where administrative duties are carried out by the staff. "The geothermal unit will provide 30 percent energy savings for building 1840 and will count towards our renewable energy credits for Edwards AFB," Hunt said.