Honolulu to Air Condition Buildings with Seawater

A new green project called Honolulu Seawater Air Conditioning (HSWAC) proposes to cool down buildings with seawater, rather than fossil fuel-based air conditioning units, and it is getting some serious green to back it. Private investors have put up nearly $11 M, completing the funding effort for the $152 M project, with about half of the final funding coming from investors from Honolulu. Construction on the project is set to start the first week of January, 2009.

The system will pump cool water, about 45° F, from 1,600 feet below the ocean waves. The water will travel through the pump system to an onshore station where it will cool fresh water that circulates in a closed loop through customers’ buildings in downtown Honolulu. Once the cold seawater has done its job, it is pumped back into the ocean at a shallower level, going through a diffuser to ensure proper mixing and dilution to the surrounding sea. I’m curious as to the maintenance requirements of this system during and after storms, though apparently the creators know what they’re doing since the VP of Engineering at HSWAC and the President of the project’s management company, Renewable Energy Innovations, LLC, pioneered the system in Sweden and have shown that it works quite well.

I’m also curious as to what fuel is going to be used to power the system. Hopefully they’ll take a hint from the newly required solar-powered water heaters and go renewable with the system. Regardless, the savings potential is astounding. Honolulu depends on imported oil and fossil fuels for 90% of its electricity, so to use seawater instead would drop costs by over 20%. Building owners are pretty peppy about this savings, and the project has already committed over half of its 25,000 ton capacity to future customers who have signed on, which even includes the Hawaiian Electric Company’s headquarters. It's a very good sign that there is so much enthusiasm behind the project from businesses and government.

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