Aquarium lifts heat from ocean's stored energy

Published on NewsOK Modified: December 16, 2012 at 6:48 pm •  Published: December 16, 2012
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SEWARD, Alaska (AP) — Alaska's Resurrection Bay teems with salmon, herring and humpback whales, but when Alaska SeaLife Center chief executive officer Tara Riemer Jones looks at the fiord outside her window, she sees a way to cut her building's heating bill.

The center this month turned off boilers that burn expensive fuel oil in favor of America's farthest north seawater heat pump system, which taps a summer's worth of solar energy stored in the deep bay.

The system sucks in seawater, extracts a few degrees of its warmth and returns it to the ocean. The upfront costs of the system were significant — about $830,000. But the SeaLife Center expects the system to pay for itself in less than nine years, saving at least $15,000 and possibly double that each winter month, with the added benefit of keeping 1.3 million pounds of carbon emissions out of the atmosphere each year.

"It working just as it was designed and we're getting huge savings out of it," Jones said.

About 160,000 visitors pass through the SeaLife Center each year to see underwater views of sea lions and harbor seals plus rare seabirds and fish from all depths. The center employs 90 people year-round and hosts volunteers and interns who help with its other missions, research and ocean wildlife rescue.

The SeaLife Center is in Seward, a city of 2,700 about three hours south of Anchorage by car. The city buys electricity from a utility that produces power mostly by natural gas, but the gas lines don't stretch to Seward. Homes and businesses burn fuel oil that in 2008 was selling for $5 per gallon.

At that price, the 120,000-square-foot building's annual heating cost reached $463,000, said operations manager Darryl Schaefermeyer.

A maintenance worker suggested heat pumps and Schaefermeyer called in Anchorage clean energy consultant Andy Baker to see if an answer to the center's heating problems could be found in its front yard.

Baker, who's also an engineer, studied systems pioneered in Scandinavian countries, visited four seawater heat exchange systems in Canada and reviewed the latest technology offered by U.S. companies. He found Resurrection Bay to be ideal.

The bay is elongated on a north-south axis and includes a 5-mile long area that's more than 900 feet deep. It collects solar energy all summer. Glacier melt adds a bit of cold water but it's largely not flushed by ocean currents, allowing it to retain heat.

"The only place it loses heat is at the surface," Baker said.

The coldest water, 37, degrees, is found at the end of winter in April. A summer of sun raises that to 52 degrees by late October. Heating that volume of water 15 degrees would take 50 days of the entire daily throughput of the trans-Alaska pipeline — 600,000 barrels — burned at 85 percent efficiency, Baker said.

"It's staggering. The sun does all that for free. We're just tapping a tiny, tiny portion of that," he said.

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