Innovation Pipeline

The planet’s oceans hold tremendous reserves of natural resources. Among those is one not-so-obvious asset: cold water. It has the potential to help cool buildings onshore in a system called seawater conditioning.

Development is moving ahead in Honolulu and San Diego. In Hawaii, a large seawater conditioning program received a $10.75 million investment by Honolulu Seawater Air Conditioning to build a plant in Kakaako, expected to be completed by June 2010.

The plant is being designed to cool 40 downtown buildings, which is expected to save as much as 16 megawatts of electricity, 265 million gallons of potable water a year and 114 million gallons of sewage created by existing air-conditioning networks.

The total estimated cost of the seawater conditioning system is $152 million. The financing of the system comes from a variety of state tax-exempt bonds and private investors.

The system draws 45-degree water from a depth of 1,600 feet some four miles off the coast of Kakaako. That water is pumped up to a 25,000-square-foot pumping station, where it is then used to cool fresh water linked to buildings’ air-conditioning systems.

The University of California at San Diego is also investigating the use of offshore seawater to help cool campus buildings. Campus officials say the seawater conditioning system would tap into the cold water of the La Jolla Canyon, a deep trench about a mile offshore from the Scripps Institution of Oceanography. Researchers are still completing a technical and environmental feasibility study of the system.

The cold water from the deep trench would be pumped to the surface, where an onshore cooling station would employ a heat exchanger to cool water for campus air conditioning. UCSD officials claim the system has the potential to save $4 million annually. About 4 megawatts of energy is currently used to power the campus cooling system. It is also expected to reduce use of fresh water on campus for cooling by more than 100 million gallons each year. By Lee Bruno