Nashville International Airport (BNA) recently converted an abandoned rock quarry adjacent to its runway into the largest geothermal cooling system of its kind in North America, which will save the airport $430,000 per year in energy costs.
The project required submerging 12 stainless steel heat exchanger plates into the quarry reservoir, which maintains a year-round 50-degree temperature. The system pumps water through a closed loop between the airport terminal's cooling plant and the submerged exchangers, turning 79-degree water into 63-degree water. It takes the water approximately 45 minutes to make the entire loop, which consists of two miles of high-density polyethylene pipe.
Garver designed the pipeline corridor, which crossed a runway and taxiway en route to the reservoir, but worked with the airport to schedule construction phasing while the runway was already closed for routine maintenance.
"Harnessing the cooling effect of the quarry water created a renewable, sustainable energy source," said Ryan Sisemore, director of Garver Aviation's East Region. "A project like this encourages innovation in the way we create solutions."
"What was maybe a liability has become a wonderful asset for us," said Christine Vitt, the airport authority's vice president of strategic planning and sustainability.