June 24, 2010 - Deep-Seawater Air Conditioning System to Cool Honolulu

Frigid seawater pumped in from the ocean's depths will soon help cool more than half of the buildings in Honolulu's downtown.

Honolulu Seawater Air Conditioning LLC, which is undertaking the $240 million project, expects its technology to cut the Hawaiian city's air conditioning electricity usage by up to 75 percent while slashing carbon emissions and the use of ozone-depleting refrigerants.

The project involves running a five-foot-wide pipeline hundreds of feet below the sea, which will then suck up thousands of gallons of frosty water and discharge it through air-conditioning units around the city, helping to cool off entire buildings. The warmed water is then dumped back into the ocean at a level and temperature that won't harm nearby aquatic life.

The company plans to break ground next summer with the first 40 buildings coming online in 2012. Hawaii's power grid is especially taxed during the day, so the seawater cooling system will help save premium power while relieving stress on the grid.

If all goes well, the technology could be extended to nearby tourism-heavy Waikiki, which uses a significant amount of air conditioning. The deep-sea system, which is already used in cities like Stockholm and Toronto, will hopefully inspire other tropical coastal areas around the world to harness the underwater technology.