Government officials and researchers from the Ministry of Environment and the Korean Water Resources Corporation (K-Water) came to visit Toronto to meet with engineers at Enwave as well as researchers at the City of Toronto. They were here to learn about Ontario’s Deep Lake Water Cooling (DLWC), which provides energy savings of up to 90%.
They said air conditioning is one of the largest energy drains in commercial buildings. Enwave, with financial backing from the City of Toronto, developed the DLWC, which basically draws water from the bottom of Lake Ontario through tubes and provides air conditioning to high-rise buildings in downtown Toronto. Cold water makes its way to the John Street Pumping Station (which we visited), where heat transfer occurs (heat from indoor air is removed) and then it continues to pump into the city for normal water supply (slightly warm by then). 
Cool fact: I learned that water is most dense at 3.98°C. As water temperature climbs above 3.98°C, water density decreases, causing water to rise. That is why deep bottom bodies of water remain a constant 3.98°C.
Learn more: https://www.youtube.com/watch?v=U2nOQnGfgf8&t=61s
THE END
English 
한국어