A signature application is Enwave Energy Corporation’s system in Toronto. Here, water is pumped from the bottom of Lake Ontario, where the water temperature is steady at about 4 degrees Celsius. The chill from this water is transferred to heat exchangers; the water is then added to the city’s water supply. The amount of cold energy collected from the lake by Enwave’s system can cool up to 100 office buildings—equivalent to about 6,800 homes—and is now tapped by numerous downtown towers. It is the largest such system in the world.