SWAC Plants Around The World
The concept of Seawater Air Conditioning (SWAC) is thought to have been first conceived in 1993 at the Natural Energy Laboratory of Hawaii Authority (NELHA) at the facility at Keahole Point on the Island of Kona (the ‘big’ island) in Hawaii. NELHA was the first location in the United States to successfully deploy a deep seawater pipeline to bring deep, cold seawater ashore for alternate energy research and development. The primary purpose at the time was to support the technological advancements of the Ocean Thermal Energy Conversion (OTEC). It was soon realized that utilizing this cold seawater as the primary chilled water resource would provide a great environmentally friendly advantage, for chemical free air conditioning and at the same time offering significant energy cost savings when compared to conventional processes. The deep ocean pipes placed in the Pacific Ocean off the Kona coast all those years ago are still functioning today, cooling the buildings at NELHA and providing nutrient rich seawater for a number of sustainable industries including, fish farming, agriculture and bottle water production.
Today, other SWAC systems are in place all over the world:
The InterContinental Resort and Thalasso-Spa on the island of Bora Bora uses an OTEC system for its air conditioning. The SWAC system accomplishes this by passing cold ocean water through a heat exchanger where it cools freshwater in a closed-cycle OTEC system. This cool freshwater is then pumped to buildings and is used for cooling directly.
Since August 2004, a deep lake water cooling system has been operated by the Enwave Energy Corporation in Toronto. It draws water from Lake Ontario through tubes extending 5km into the lake, reaching a depth of 83m. The SWAC system, part of an integrated district cooling system that covers Toronto's financial district, has a cooling power of 59,000t (207MW). The SWAC system currently has enough capacity to cool 3,200,000 m2 of office space, making it the largest system in North America.
In addition to the SWAC system in Toronto, Canada has two operational systems at Halifax, Nova Scotia. The original system at Purdy’s Wharf was the world’s first and has been operational since 1986, cooling a 700,000-ft2 office complex. The second system at Alderney 5 became operational in February 2010, cooling a 330,000-ft2 office building. The Directors report that the two systems offer an annual $400,000 cost saving when compared to traditional air conditioning systems.
Closed Cycle SWAC systems are in operation at both the Excelsior Hotel and the HSBC office tower in Hong Kong
In the spring of 2006, a district cooling system was completed to cool the Zuidas District in Amsterdam. The system draws cold lake water from the nearby lake Nieuwe Meer at a depth of 30m. It is capable of cooling a load of 17,000t (60MW). A second system became operational in 2009, cooling the Zuidoost district of Amsterdam. This system is capable of cooling a load of 18,000t (64MW). Both systems are operated by Nuon (www.nuon.com), a subsidiary of Vattenfall, one of Europe’s largest electricity companies and Europe’s largest supplier of heat.
Stockholm’s 80,000t SWAC system began operations in 1995 with, at that time, the world’s largest seawater cooling system. Stockholm Energy constructed the system. An important component of Stockholm's seawater project is the use of a cold-water storage facility. At night, when the demand for cooling is lower, the facility can store any excess cold water and later supply that water when demand increases during the warmer hours of the day.
In September 2011, Google opened a data center in Hamina, Finland that uses seawater from the Gulf of Finland to cool the facility. (http://www.google.com/about/datacenters/locations/hamina/) The data center serves users in Europe and around the world, and it is the first of its kind.
Cornell University’s lake source cooling system uses Cayuga Lake in New York as its heat sink to operate the central chilled water system for its campus and to also provide cooling to the Ithaca City School District. The system has operated since the summer of 2000 and was built at a cost of approximately $60m with a financial payback of approximately 15 yrs. It cools a 14,500t (51MW) load.
Ocean Thermal Energy Corporation (OTE) has signed a 20 year agreement with the luxury Baha Mar Resort in The Bahamas to supply SWAC to a number of hotels and a 100,000 ft2 casino.