Lake Ontario water cools Toronto’s financial district

Toronto’s Deep Lake Water Cooling system was officially opened on August 17. The system is one of the largest of its kind and is providing air conditioning to several buildings in downtown Toronto. <br>
The water is drawn by three new intakes from 83 metres below the surface of Lake Ontario, where the temperature is a more or less constant 4 degrees C. At the John Street Pumping Station a bank of heat exchangers transfer the cold energy to Enwave’s closed loop system. A supplementary cooling plant with an additional centrifugal chiller is located in the Metro Toronto Convention Centre sends the water to office buildings in the downtown financial core. <br>
The Mitchell Partnership were consulting engineers on the heat exchange part of the project (see Canadian Consulting Engineer, December 2001 issue, pages 22-24 for a full article on the system design — searchable through our website archives). <br>
The cooler lake water also gives Toronto residents better drinking water. Before the new intakes were installed, much deeper and farther offshore (five kilometres) than the original ones, the city’s water was warm and had an odour during the late summer. The cold water supply now will be around 12.5 degrees C after it has transferred heat to the Enwave district cooling system and moves on to be distributed as potable water. Return water from the district system enters at 13.1 degrees C and is cooled down to 5 degrees C from the borrowed chill from the deep lake water.<br>
The system has a capacity of 59,000 TR, enough to air condition 100 office towers, or 32 million square feet of building space. It has many environmental benefits including reducing the noise and air pollution that would be generated by conventional chillers and cooling towers on office towers. Compared to conventional chillers, the system is expected to reduce energy use by 75% and will avoid 40,000 tonnes of carbon dioxide emissions — equivalent to taking 8,000 cars off the road.<br>
Some of Toronto’s best known buildings are being cooled by the system. They include the Metro Toronto Convention Centre, Air Canada Centre, Royal Bank Plaza and Toronto Dominion Centre. Enwave is owned by the City of Toronto and the Ontario Municipal Employees Retirement System.<br>
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