b'44 SDFOPERATIONSFor starters, the system will include 85 heat pumps andThe distance to the terminal was longer than what a typical roughly 709,000 feet of high-density polyethylene pipes in variousgeothermal system design would call for, Mayer notes. Distance diameters. The 500-foot-deep bore holes that hold the ground- is important because youre running the pipes underground, and loop supply and return pipes are 6 inches in diameter; the pipesthere are a lot of existing utility lines to run through as well as are 1 inches in diameter. The space between the pipes andtaxiways and ramps to tunnel under.ground is filled with grout. To protect pipes from the weight of aircraft using the taxiways, The grout is very important because its a good heatthe horizontal runs of piping between the vaults and terminal are conductor, so it helps transfer the heat from the ground to theburied 6 feet deep instead of the typical 4 feet. In addition, the water inside the pipes, Mayer explains. Without the grout, therepaved area atop the well field provides a much thicker layer of would only be air, which acts as an insulator, not a conductor. protection than a conventional design. It includes about 12 inches The well field is divided into three sections, each with a buriedof sand topped with roughly 2 feet of gravel, 6 inches of asphalt concrete vault that contains 14-inch-thick walls. The largest vaultand 17 inches of concrete. is 20 feet long, 11 feet deep and 13 feet wide; the other two vaults are slightly smaller.Resilience and RedundancyThe three vaults are interconnected as a precautionary measure. If Circuits of ground-loop pipes emerge from the wells andtheres a problem with a circuit, which Mayer says is unlikely, theres connect to the vaults. Each circuit is composed of pipes from 24redundancy built in to maintain heating and cooling operations. to 28 wells, and there are 24 circuits overall. Each vault receives eight circuits.The system also includes sensors to detect pipe leaks, and controls that monitor the return and supply ground-loop pipes. This Two 8-inch-diameter pipes emerging from the vaults carryhelps ensure that the heating or cooling load is equally distributed water into the terminal, about 1,200 feet away, and into the heatamong all the circuits, and that there is effective heat conductivity pumps.between water in the ground-loop pipes and the ground. Solutions that rethinktomorrow and deliver todayCombining practical experience with innovative approaches, Pond is a trusted advisor in preparing airports for a more resilient future.Thatsthe powerpondco.com/aviationofPond.November | December 2022AirportImprovement.com'