Summary

Seawater/Lake Water Air Conditioning (SWAC/LWAC) technology produces air conditioning without the use of chemical agents. Acting alone, SWAC/LWAC can reduce electricity usage by up to 90% when compared to traditional air conditioning systems. When developed in conjunction with Ocean Thermal Energy Conversion (OTEC) plants, it operates entirely without the use of fossil fuels.

An environmentally responsible technology, SWAC/LWAC plants use less fresh water and reduce environmental impact when compared to traditional air conditioning methods. SWAC/LWAC systems are ideally suited for large commercial operations such as resorts, hospitals, airports, shopping centers, and even entire cities.

How It Works

SWAC/LWAC plants range in size from 400 to 80,000+ tons of cooling capacity, and draw millions of gallons of cold water from an ocean or lake to act as a cooling agent for large-scale air conditioning. As the cycle completes, it can be combined with a nearby desalination plant to provide fresh water.

HISTORY OF SWAC/LWAC

The Natural Energy Laboratory of Hawaii Authority (NELHA) developed Seawater/Lake Water Air Conditioning in the 1980s while conducting research and development for Ocean Thermal Energy Conversion (OTEC). Using the same underwater pipes to draw cool water from the depths of the ocean, NELHA concluded that it could develop chemical free air conditioning while offering significant savings when compared to conventional practices.

The pipes placed in the Pacific Ocean off the coast of Kona still function and continue to provide cooling for the NELHA buildings today. A proven technology with years of global success, SWAC/LWAC systems are currently running all over the world.

Locations Around the World

• Nassau, Bahamas: Ocean Thermal Energy Corporation (OTE) designed a large SWAC/LWAC system for the Baha Mar resort in The Bahamas.
• Bora Bora, French Polynesia: The InterContinental Resorts and Thalassa-Spa on the island of Bora Bora uses a SWAC/LWAC system in conjunction with a deepwater spa. Learn more here.
• Toronto, Canada: The Enwave Energy Corporation developed a Lake Water Air Conditioning (LWAC) system in Lake Ontario in 2004. An integrated district cooling system, it covers Toronto's financial district and has a cooling power of 59,000t as well as the capacity to cool 3,200,000 m2 of office space. It is currently the largest system in North America. Learn more here.
• Halifax, Canada: The world’s first SWAC/LWAC system has been operational since 1986 at Purdy’s Wharf, and cools a 700,000 square foot office complex. An additional system at Alderney 5 became operational in February 2010, cooling a 330,000 square foot office building. Reports show that the two systems save $400,000 annually when compared to traditional air conditioning systems.
• Hong Kong, China: Closed Loop SWAC/LWAC systems are operational at both the Excelsior Hotel and the HSBC office tower in Hong Kong.
• Amsterdam, The Netherlands: In the spring of 2006, a district cooling system was completed to cool the Zuidas District in Amsterdam. The system draws from the nearby lake, Nieuwe Meer, and has the capacity to cool a load of 17,000t. In 2009, a second system was built in the Zuidoost district, which is capable of cooling a load of 18,000t. Both systems are operated by Nuon (a subsidiary of Vattenfall), one of Europe’s largest suppliers of heat and electricity.
• Stockholm, Sweden: Stockholm Energy constructed an 80,000t SWAC/LWAC system in 1995, and it was the world’s largest seawater cooling system at that time. At night, when the demand for cooling is lower, the facility stores excess cold water for later use when demand increases.
• Hamina, Finland: In September 2011, Google opened a data center in Finland that uses seawater from the ocean to cool the facility. The data center serves users in Europe and around the world. Using seawater cooling in this manner is a world first.
• New York, United States: Since 2001, Cornell University’s lake source cooling system has used Lake Cayuga as its heat sink to operate the central chilled water system for its campus and the Ithaca City School District. The cost of development was approximately $60 million with a financial payback of approximately 15 years. It cools a 14,500t load. Lanny Joyce, who managed the design and development of this system serves on the Ocean Thermal Energy Corporation Advisory Board.