A Dip in the Lake: Using LakeWater to Cool HVAC

By Consulting Specifying Engineer Staff May 2, 2006

Increasing energy efficiency and lowering costs while satisfying comfort-demanding consumers and protecting the environment is no small task. A recently completed project in Toronto, Canada, is an example of what can happen when all the right components are in place.

The key was drawing icy water from the lake, and using it to chill the water used to air condition downtown buildings. Water at 4

The project was initiated by Enwave District Energy Ltd., an organization owned 43% by the city of Toronto, and 57% by the OMERS pension fund (the Ontario Municipal Employees Retirement System). It’s already at work, cooling over 20 buildings in downtown Toronto, including the Toronto Dominion Centre, the Air Canada Centre, and the Royal Bank Plaza, and there are plans to increase this list in the very near future.

Why does it work? The short answer is, because every single element works the way it’s supposed to. The longer answer addresses the different components of the innovative system. It begins with three 5-km (3.10-mile) high-density polyethylene pipes that reach 83 m (272 ft.) down to the bottom of Lake Ontario to draw the icy water and send it to purification systems at the Toronto Island Water Filtration Plant. Here the water is screened, pre-chlorinated, filtered, disinfected, fluoridated and post-chlorinated.

Giving an example of the importance of every detail, Pat Cimek, area manager for E.S. Fox, the construction and fabrication specialists hired by Enwave, comments: “In our type of work, there’s no such thing as a small detail; everything we use, we do because we know it will perform for us.” An integrated company that provides a single source for industrial construction and fabrication, E.S. Fox undertakes total-responsibility projects, providing a combination of engineering, procurement and construction skills. Cimek mentions they expect 99.999% reliability on all the components they employ on their systems

When it was time to spec the variable frequency drives for operating the Dezurik AWWA butterfly valves that control the volume and flow of water, Cimek, his team of consulting engineers and the purchasing department, turned to E.S. Fox’s long-time supplier, Sterling Power Systems. “As a company, they offered us the advantages of trust and comfort; and we know they can program and start-up the drives on site,” explains Cimek, and he continues

What’s so cool about the so-called deep-water lake project? A couple of things stand out right away. One is the savings factor. It is estimated that the project will save 59 megawatts of capacity to the province of Ontario, which can be translated into the electricity needed to power the air conditioning systems in 12,000 homes. If that’s not enough, there’s another benefit—this alternative source of energy is an environmentalist’s dream. It has been estimated that air pollution reduction from the system will be the equivalent of taking between 4,000 to 8,000 cars a year off the road!

It makes sense. Right from the beginning, it was a plan that made sense. It started by combining the needs and wants of consumers with overall business and conservancy objectives. It continued with the development of a system that’s designed around available nature’s resources, in this case, chilly water from the lake; and taking advantage of proven, cost-effective and reliable technology.

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