About District Cooling >> Case Studies
Numerous Case Studies Support District Cooling
Makai Ocean Engineering, Hawaii
District cooling and seawater air conditioning (SWAC) takes advantage of available deep cold seawater instead of energy-intensive refrigeration systems to cool the chilled water in one or more buildings. Click here for more information.
Ithaca, New York
Cornell University is consuming much less energy and helping regional electric power plants release fewer pollutants into the air thanks to the university’s innovative Lake Source Cooling project, which uses naturally cold, deep water from Cayuga Lake to cool campus buildings.
Although the concept is not new, this is the first such installation by a university anywhere in the world and also the first to be installed in a small freshwater lake. The Lake Source Cooling project began providing 16,000 tons of cooling to Cornell University’s Ithaca campus in July 2000, resulting in an 86 percent reduction in energy use for campus cooling.
The system draws 39˚F water from a water depth of 250 ft. The cold water is piped to a shoreline heat exchange facility, where it transfers its coldness to water that circulates to the campus in a second loop of pipeline. Water drawn from deep in the lake is returned at a water depth of 10 ft. The only change in the Cayuga Lake water is the addition of heat, all of which is released each winter. Click here for more information. Click here for a video explaining lake source cooling.
Click here for more on this project (National Renewable Energy Laboratory)
The Toronto Deep Lake system was developed in conjunction with the City of Toronto’s freshwater acquisition development. It is one of the largest renewable lake source systems in the world in connection with a municipal dual drinking water and cool energy service.
The Toronto project utilizes a three-intake pipe system with an intake at a depth of 270 ft. The lake water distribution piping system brings the cold water to a pumping station. Heat exchangers are used to extract the coldness from the drinking water to a closed-loop distribution system that is connected to individual buildings for air conditioning purposes. The heat exchanger separates the district cooling closed-loop system water from the cold drinking water that is distributed throughout the City of Toronto.
"To anyone who's taken a dip in Lake Ontario, it seems like a no-brainer: Use the lake's icy waters to keep nearby cities cool." Toronto did just that by designing and operating a $170 million (U.S.) deep-lake water cooling system, the largest of its kind. Click here for more information.
Sweden is a world leader in SWAC development. There are currently more than 80,000 tons of deep lake SWAC in Stockholm. Several other cities, including Jönköping, Upplands Väsby, Solna, Sollentuna and Södertälje, have SWAC systems with up to 15,000 tons of capacity.
Anders Rydåker and Ingvar Larsson, two members of the Honolulu Seawater Air Conditioning management team, were actively involved in the development of these systems. In 2003, Rydåker received Sweden’s Prestigious Energy Prize for pioneering the development of numerous district cooling systems in the country.
The energy company Nuon is the first supplier of district cooling in the Netherlands. District cooling is delivered to customers in the business districts of Zuidas and Amsterdam-Zuidoost on the outskirts of Amsterdam.
The cooling is produced by making use of the low temperature of the deep waters in the lakes Nieuwe Meer and Ouderkerkerplas. Cold water from the depth is pumped from the lakes in a constant cycle to the production sites, where it cools the transport water in the pipes of the cooling network. Afterwards it is pumped back in to the lakes, where it quickly returns to the ambient temperature. The aggregated capacity of the two systems is more than 35,000 tons of cooling.