Hawaii uses Cold Ocean Water for Air Conditioning
As consumers approach the time of year when opening energy bills can trigger serious pain in the pocketbook, the State of Hawaii is working with Ever-Green Energy to reduce grid power consumption by using cold seawater to help chill office buildings. The technology is called seawater air conditioning, and the Downtown Honolulu Seawater Air Conditioning Project is anticipated to save 77 million kilowatt hours per year when it becomes operational in 2012.
Honolulu Seawater Air Conditioning, Ever-Green's local developer, is currently developing the downtown Honolulu 25,000-ton seawater air conditioning cooling system. The firm will build pipes to extract seawater four miles offshore at a 1600-foot depth and bring it to an onshore cooling station. Since seawater is about 45 degrees Fahrenheit, the onshore cooling station will use the chilled water to cool fresh water to the 44 degree temperature used in chillers in office buildings. The warmed seawater will be returned at an appropriate depth within the ocean to prevent harm to the environment.
Ever-Green will own and manage the seawater air conditioning facility through a subsidiary once it is completed. Additional benefits include a 20% reduction in cooling costs, elimination of 84,000 tons of CO2 emissions, and a reduction of 84 million gallons of sewage from conventional cooling towers.
The technology described here is not brand new, and has been used successfully in other locations, such as Toronto, Ontario, and St. Paul, Minnesota. It continues a long tradition in Hawaii of studying and utilizing Ocean Thermal Energy Conversion.