Passengers at Seattle-Tacoma International Airport will be breathing a little easier thanks to a new air network that reduces fuel use by planes waiting at the gate.

To cool or heat passenger cabins, planes have historically used their own auxiliary power, which burns jet fuel, or relied on diesel generators. But last month Sea-Tac launched a new “preconditioned air” network, which cools or heats air at a central plant and then pumps it through hoses onto the plane, The Seattle Times reported.

That means less exhaust hovering over the tarmac.

So far, 29 gates are using it, and all 73 gates will supply preconditioned air by the end of this year — making Sea-Tac the largest airport in the U.S. to supply every gate with preconditioned air, said airport spokesman Perry Cooper.

United Airlines’ station manager at Sea-Tac, Jonna McGrath, said the system reduces fuel consumption by 40 to 100 gallons each layover because the planes don’t have to supply their own energy. The airline also uses preconditioned air at several other airports, including in Houston, Chicago and Denver.

Considering a jet-fuel cost of around $3 per gallon, “I can save up to $300 an hour,” McGrath said.

The system includes a vast “chilling room” beneath the air terminal’s food court, where a pink glycol-water mixture circulates in four 750-ton chillers cooled by electric power. Alongside them are 16 steel tanks full of ice. Coolant flows mainly through the ice tanks, or directly from the chillers, before it travels to the gates.

Reaching the gate, the coolant next circulates through smaller pipes inside a huge box — where outdoor air is being sucked in and chilled. The cooled air is filtered and then pumped to the aircraft.

The heating pipes have been hooked to the same steam plant, fired by natural gas, which heats the terminal buildings.

Fifteen miles of pipes connect the chillers and heaters at Sea-Tac to the gates.

Connecting the entire airport should reduce global-warming emissions comparable to taking 8,000 cars off the road, according to the Port of Seattle.

The conversion cost $43 million, half of it paid by a federal air-quality grant and half by the gate fees airlines pay. Airlines expect to save $15 million a year and to recoup their cost within three years.

Other recent clean-air projects by the Port of Seattle include centralizing rental-car operations in a new building north of the airport, where compressed-natural-gas shuttles carry arriving passengers to the car center. This reduces some 165,000 vehicle trips per month to scattered rental locations.


Information from: The Seattle Times,

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Photo Credit: Cooled air from an energy-efficient and cleaner "preconditioned air" system at Seattle-Tacoma International Airport is pumped into aircraft, reducing toxic air that hovers above the tarmac. Port of Seattle