SEA-TAC AIRPORT -- There's almost nothing that feels hotter than being stuck inside a plane on a hot day with no air conditioning. The solution for airlines is to run the jet fuel-powered auxiliary power unit to keep the planes internal air conditioning system running while cleaners ready the plane for its next flight and you get on board.
With jet fuel pushing $3.00 a gallon, a plane like a Boeing 777 can consume 40 to 100 gallons in an hour keeping the interior cool as the airline turns a big international flight, according to Jonna McGrath, United Airline's general manager for operations at Sea-Tac Airport. That comes to around $300 an hour for fuel burned.
But why run the internal air conditioning packs when the plane is standing still? Enter the idea of central air conditioning for the airport. As of today, Sea-Tac has on line a central cooling unit to provide "pre-conditioned" air directly to the gates. Sixteen gates are hooked up now, and the rest of the airport's 73 gates are expected to be done by the end of the year. So instead of spending $300 on fuel to cool the 777, spend $5 in electricity to get the same benefit.
Does it save money and emissions? Sea-Tac and United say most definitely. The airport claims together all airlines are expected to save about $15 million a year.
"We actually get the entire project paid off, a return on investment in under three years. Said Elizabeth Leavitt Sea-Tac's Director of Aviation Planning and Environment.
It cost $45 million to build the plant and hook everything up.
A large centralized cooling plant actually delivers sub freezing water to an exchanger at each gate through a network of 15 miles of pipes. The exchanger cools the air, which is pumped through the belly of planes through large yellow tubes. As it comes out through the vents it's up to about 55 degrees Farenheit. That saves five million gallons of fuel, according to port estimates, and cuts carbon dioxide and other emissions.