Hydrothermal Cooling: Improving on Air-Conditioning


Unlike the rest of us who are still eagerly awaiting the release of a solar powered air conditioner to quench our hot summers, Canadians living in Toronto have found a cheap and sustainable way to stay cool. Drawing on the large supply of cold water from Lake Ontario, the city's residents have pioneered a method of directly extracting the "cold" to power their air conditioning systems.

Three pipes running 3 miles (about 5 km) into the lake to a depth of approximately 83 m pump 4°C water to a filtration plant and then to a heat-transfer station located on its shores. The system, built by Enwave Energy Corporation, transfers the "cold" to a closed loop of smaller pipes that in turn supply the towers of Toronto's financial district. Businesses have been particularly keen to use this technology as it has allowed them free up space on their roofs previously used by cooling units to invest in more office space or other facilities. Officials at the Toronto Dominion Center, a set of five office towers, estimate that the technology, which has already been incorporated into three buildings, has saved them 7.5 megawatts of electricity. Once the remaining towers are modified to implement this system, they estimate another 2.5 megawatts of electricity will be saved. With plans in place to connect up to 52 more buildings to the cooling technology, the project is expected to reduce Toronto's energy needs by a whopping 61 megawatts.

But that's not all.

In addition to being the largest such project in the world, Toronto's system is also the only one that combines cooling with drinking water (water from the lake provides about 15% of the city's supply).

Now other cities and institutions are ratcheting up their efforts to establish similar projects: Stockholm's system, which relies on seawater, is about two-thirds the size of Toronto's while the system used by Cornell University extracts its cold from Lake Cayuga's waters. Geneva and Tokyo are both looking at possibly investing in such a scheme. Other cities that had originally been interested in such a project, including Chicago and New York, were unable to move forward due to spatial and depth constraints on their sources of water.

Image courtesy of The Economist

Via ::A cool concept

See also: ::Cooling London's Tube Trains With Ice, ::Eureka! The Solar Driven, "Water-Fired" Chiller-Heater, ::Local Cooling: Tuning Your Computer to Save Energy, ::Air Conditioner in a Can from Japan, ::Solar-Powered Air Conditioner About To Be Released

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