VFDs critical to deep-water project

Increasing energy efficiency and lowering costs while satisfying demanding consumers and protecting the environment is no small task. It requires a fundamental commitment and needs to rely on solid, proven technology. A recently completed project in Toronto is a great example of what can happen when all the right components are in place.

The key to the project is drawing chilly water from the Lake Ontario and using it to cool the water used to air-condition downtown buildings.

Water at 4C is taken from the bottom of the lake and sent to the Toronto Island Water Filtration Plant to be purified. The treated water is then forwarded to a heat transfer station and used to lower the temperature of the process water.

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 more than 20 buildings in downtown Toronto.

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 high-density polyethylene pipes, a total of 5 km long, that reach 83 m down to the bottom of Lake Ontario to draw the water.

At the plant, the water is screened, pre-chlorinated, filtered, disinfected, fluoridated and post-chlorinated. The process continues with the pumps at the heat exchange station, the butterfly valves that control the flow and volume of the water, and the variable frequency drives that operate the valves. Every single link in this chain has to work at top performance.

Pat Cimek, area manager for E.S. Fox Ltd. of Niagara Falls, Ont., the construction and fabrication specialist hired by Enwave, says: “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.”

Cimek says that the company expects 99.999% reliability on all the components employed on its systems.

Valves driven by VFDs

When it was time to spec the VFDs (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 of Hamilton, Ont.

“As a company, they offered us the advantages of trust and comfort, and we know they can program and startup the drives on site,” explains Cimek. “And we agreed with Sterling Power’s recommendation of AC Technology drives based on their proven quality, performance and competitive pricing.”

A couple of things stand out right away about the deep-water lake project. One is the savings factor. It is estimated that the project will save 59 megawatts of capacity for 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 the air pollution reduction from the system will be the equivalent of taking between 4,000 to 8,000 cars a year off the road.

Right from the beginning, it was a plan that made sense. It involved the development of a system that’s designed around available natural resources, and taking advantage of proven, cost-effective and reliable technology.

For more information, contact E. S. Fox at www.esfox.com, Sterling Power Systems at www.sterlingpowersystems.com, and AC Technology at www.actech.com.