Future

Energy Sources

Air conditioning is among the largest uses of electricity in many Hawaii homes and businesses. For example, it is estimated that half the energy consumed in Waikiki is for air conditioning*.

A sea water air conditioning (SWAC) system (also called district cooling) can be a cost-effective use of a renewable energy source to offset the conventional air conditioning that consumes four to 12 times more electricity.

With SWAC, cold sea water is pumped from hundreds of feet below the surface to a cooling station on shore. This station transfers the salt water’s coldness to fresh water circulating in a closed loop that carries it to customer buildings. The cooling station ensures that sea water and fresh water never mix. Warmed sea water is returned to the ocean through another pipe and diffuser located at a shallower depth.

This system is a proven technology already in use at the Natural Energy Laboratory of Hawaii Authority in Kailua-Kona on the Big Island. The University of Hawaii John A. Burns School of Medicine in Honolulu (Kakaako) uses cold well-water to reduce its air conditioning costs. Also on Oahu, Honolulu Seawater Air Conditioning has an ambitious plan to create a SWAC system to cool about 40 buildings in downtown Honolulu.  The system would draw water from the ocean floor four miles off the Kakaako coast at a depth of 1700 feet, where water temperature is 45 degrees year round.

Other examples of SWAC are: Toronto, Canada is developing a district cooling system using cold water from Lake Ontario. Cornell University in New York is cooled with water from Lake Cayuga. Sweden is a world leader in SWAC development.

Hawaii-based Makai Ocean Engineering is an acknowledged world leader in the underwater pipelines that are an essential part of sea water air conditioning.

More on Sea Water Air Conditioning:

honoluluswac.com

www.makai.com/p-swac.htm

www.seaconinternational.com

*From Honolulu Seawater Air Conditioning, LLC