80% Savings on Air Conditioning With Sea Water

Deep cold seawater can be a practical and economically viable source of cooling in a centralized air conditioning system. A seawater air conditioning system (SWACS) uses cold sea water from approximately 2000 ft depth to cool (via a heat exchanger) a centralized fresh chilled water distribution loop serving multiple buildings. At ideal coastal sites, SWACS power savings can approach 80% compared to conventional chillers. _IEEE

Anywhere on Earth with easy access to seawater roughly 2000 ft. deep can save 80% to 90% on its energy expenditure for air conditioning. It is being done in Hawaii

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. _Ecogeek

A similar project is being carried out in Curacao.

The pipeline will reach 6 kilometres out into the sea, going south out from the Marriot Hotel, down to a depth of 850 meters, fetching up seawater at a temperature of 6°C at half cubic meter per second. The SWAC system operates with a temperature differential (ΔT) between the water it takes in and the water it lets out of about 7°C, and the return water will go into the sea again at 100 meters depth to avoid any substantial environmental impact. _OTECNews

On an island, fuel must be shipped in, and is very expensive. Saving 80% on energy costs of air conditioning in a tropical island environment means a very large reduction in fossil fuel consumption. The main costs for such a seawater chiller system are electricity for pumps and routine maintenance.