Saturday, December 4, 2004


Cold-water air-
conditioning project
merits warm reception


A company hopes to install a facility in Kakaako to use cold sea water to chill the air in buildings.

USING cold ocean water to adapt conventional air-conditioning systems would reduce fossil fuel consumption and suitably employ a renewable natural resource in Hawaii. Such enterprises deserve the support of the state after potential ecological effects are analyzed.

The proposal from Honolulu Seawater Air Conditioning, a local subsidiary of a Minnesota-based company, would place a pumping station near the fast-developing Kakaako waterfront. The company has asked the Hawaii Community Development Authority for a lease option in the area, critical not only for drawing water, but also to be close to potential customers.

Cold water from a depth of 1,600 feet would be drawn through a pipeline about 3.5 miles offshore and used to chill fresh water that, in turn, would cool air circulated in buildings. In conventional air conditioning, electricity powers cooling systems.

Honolulu Seawater says its method would cut fossil-fuel consumption by a whopping 80 percent. The company's claim isn't unrealistic. A similar plant used at Cornell University has brought an 86 percent reduction in energy use, exceeding expectations by 6 percent. For businesses in Hawaii, where electricity rates are among the highest in the nation, the savings would be tremendous, especially since air conditioning accounts for about 40 percent of energy costs in an office building.

Cold-water cooling has been used successfully at the Natural Energy Laboratory Hawaii Authority on the Big Island, though on a much smaller scale of three buildings, where Honolulu Seawater hopes to sign up 65 buildings in the downtown-Kakaako areas.

Cornell's plant, which cools the entire campus and a nearby high school, has been in operation for four years. In August, the city of Toronto put a system on line that will eventually cool 30 million square feet of office space with a 75 percent energy saving.

The difference, however, is that both Cornell's and Toronto's plants pump from lakes. Toronto is recapturing the fresh water for drinking, but because Cornell is pumping warmed water back into the shallows of Cayuga Lake, there has been concern about algae and bacteria blooms in a recreational area.

Hawaii's system will draw from the ocean and the warmed salt water will be pumped back at a depth where water temperature will be about the same, which the company says shouldn't affect the ocean environment. Even so, state authorities should be mindful of siting, potential effects on sea life and human activity, and disruptions installing the necessary network of pipelines would cause.

That said, it appears Honolulu Seawater's plan adapts well to Hawaii's goals to lessen oil dependency and for sustainable alternatives. It is a project that fits the state's needs and its resources.

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