Honolulu Seawater Air Conditioning (HSWAC) is currently developing a 25,000-ton SWAC district cooling system for the buildings of downtown Honolulu. 

According to the company’s press release, SWAC is suitable for coastal developments with a large air conditioning demand and reasonable access to deep, cold seawater.

The big benefit of the system is reduced energy use. Pumping cold seawater uses dramatically less energy than using compressors in conventional air-conditioning units, a particular bonus in a high-energy-cost state like Hawai'i.

Honolulu Seawater Air Conditioning has released the preparation notice for its environmental impact statement, the first step in a required review process.

The project cost is estimated at $145 million and the company hopes to have the system operating by late 2009, after a 14-month construction period. Seawater air conditioning, although new to Hawai'i, is a mature technology. A system in Stockholm, Sweden, started cooling buildings in 1995.

There also are systems at Cornell University (New York), Toronto (Canada) and Bora Bora (French Polynesia).

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