Seawater Air Conditioning (SWAC) 101

How Does It Work?

Seawater Air Conditioning (SWAC) systems use the unlimited natural resource of cold, deep ocean water as the chemical-free cooling for large scale air conditioning needs, including resorts, hotels, hospitals, shopping malls, airports, large buildings, and data centers.

While an OTEC plant has two pipes (one warm water pipe and one cold water pipe), an SWAC plant has only one pipe…the cold water pipe, which brings up the chilly deep ocean water. This cold deep water is used to cool buildings (see Figure 1), reducing electricity usage by 80%-90% when compared to conventional AC…saving the typical customer millions of dollars in electricity bills over the life of an energy service agreement with Ocean Thermal Energy Corporation (OTE).

When the process is complete, SWAC plants can desalinate the seawater into fresh water for drinking, aquaculture, and agriculture.

Environmental Benefits

  • Environmentally benign
  • Uses up to 90% LESS electricity than conventional systems and without the use of chemicals
  • Available 24 hours a day, 7 days a week, 365 days a year
  • Produces fresh water for drinking, sustainable fish-farming and agriculture
  • Reduces carbon emissions by 80-90%
  • Reduces electrical usage with a renewable resource
  • Reduces use of ozone-depleting chlorofluorocarbon (CFC) refrigerants
  • Reduces reliance on fossil fuels and emission of greenhouse gases
  • Uses less potable water and discards less toxic water to sewers

Economic Benefits

  • Scientifically and commercially proven with numerous examples around the world
  • Dramatically reduces energy costs
  • OTE has over 25 years of experience with SWAC systems
  • Price competitive service with stable energy cost throughout the life of the contract
  • Model of sustainability with fuel dollars staying in the local economy
  • Eliminates the need for chillers or cooling towers
  • Equipment built to last 75 to 100 years is easy to operate and maintain

Clean Water

  • OVER 1 BILLION people in emerging markets are paying high energy prices from fossil-fuel generated power. They are short of clean drinking water and are often malnourished

  • At least 700 million lack access to safe drinking water

  • The world will face a 40% shortfall between forecasted demand and available supply of water by 2030

  • By 2025, about 1.8 billion people will be living in regions or countries with absolute water scarcity

  • The world needs to produce at least 50% more food to feed 9 billion people by 2050


Figure 1 - How It Works

SWAC systems can save up to 90% in electricity costs when compared to traditional air conditioning systems. SWAC systems range in size from 400 to 80,000 tons of cooling capacity and use millions of gallons of seawater. Once the seawater has been used for air conditioning it can be desalinated for potable water

SWAC Model – deep seawater is used to chill a freshwater loop that in turn cools the buildings. Seawater is returned to the ocean at exactly the same ambient temperature.

Figure 2 - SWAC Rendition

Rendition of our planned SWAC system for the Baha Mar Resort in The Bahamas