Canadian Consulting Engineer

Power + Heat at 341 Bloor Street

May 1, 2008
By H. H. Angus & Associates

Emergency power is traditionally provided by diesel generators that sit dormant in building basements and penthouses for more than 98% of their lifetime. The situation is inefficient, and sometimes da...

Emergency power is traditionally provided by diesel generators that sit dormant in building basements and penthouses for more than 98% of their lifetime. The situation is inefficient, and sometimes dangerous if the diesel fuel is not stored properly.

Recent changes in the Canadian Standards Association requirements for emergency power systems in buildings, however, are leading to new methods of leveraging what was once a stranded asset. This Toronto project took advantage of the change to CSA-282 that now allows off-site utility gas to be used for on-site emergency fuel.

The Senator David A. Croll Apartment building at 341 Bloor Street West in downtown Toronto was built in the 1960s on the edge of the University of Toronto campus. Once known as the infamous Rochdale College, it is now a fairly typical multi-residential building — 305 units and a 24-hour grocery store on the main floor — managed by the Toronto Commission Housing Corporation.

The building had a traditional emergency power system, but this changed one cold night in January this year. A 550-ton mobile crane blocking Bloor Street in both directions performed a 16-storey lift of a 40,000-lb package containing a complete Combined Heat and Emergency Power plant (CHeP). One of the biggest cranes in North America, it attracted quite an audience.

The combined heat and emergency power system is based around a 335-kW Jenbacher 208 reciprocating natural gas-fired engine-generator. The system is installed to replace the aged 125-kW diesel generator that is still located in the basement. The new engine is installed on the roof of the building and runs on natural gas from the utility. In contrast, conventional generators rely on diesel fuel, which is usually stored on site in above-and below-ground storage tanks.

The new generator produces enough electricity for the entire building load on most days. The heat generated by the engine is captured from the machine and the exhaust, and it is used to heat the domestic hot water system and the building spaces, thereby producing a very efficient use of the fuel — greater than 90%.

The system brings enormous value to the facility. Not only does it increase the emergency power load to near peak load, but also it reduces emissions and eliminates transmission losses, thus reducing the need for expanded power generation.

The most important change to the residents of the building will be the increased emergency power load capabilities. Instead of running only a minimum of elevators and emergency lighting during power outages, the CHeP system provides a power load that runs all the regular systems, including the heating and air-conditioning systems. Thus residents can carry on with their activities and suffer no apparent impact in case of a local utility power failure.

The new system not only improves the quality of life for the residents, but also improves security for them and the community, by allowing businesses to remain open.

The value doesn’t come without challenges: finding a location for the new CHeP plant was not a simple process. Buildings often have the heating system in one location and the emergency power systems in another, which was exactly the case for this project. The boilers were in the penthouse and the generators were in the basement. Running new cabling or heating pipes through an existing building can be prohibitively costly. The installation requires tie-ins to existing systems, approvals from the utility authorities, and certificates of approval for air and noise.

What does a building need to suit a CHeP system? It needs to have a large enough electrical load to justify the smallest gas turbine. The 335-kW unit used on 341 Bloor is the smallest built by GE. The building also has a consistent hot water heating load to make the efficiency of the CHeP competitive with current electrical rates. Such a system only becomes an option when looking at aging equipment that requires replacement and capital investment.

The CHeP system was pioneered by OZZ Corp and HH Angus for the Villa Colombo project in Kleinberg, Ontario two years ago. The 341 Bloor Street system was a first in Toronto and was carried out with financial help from the Toronto Atmospheric Fund and Natural Resources Canada. Now, the Toronto Community Housing Corporation is studying two other buildings with aging emergency power systems to evaluate the feasibility of CHeP.

The landscape for small power generation projects like this looks promising. For example, the Ontario Power Authority is expected to release its Clean Energy Standard Offer Program soon, which could provide financial incentives for similar projects.

Client: Toronto Hydro Energy Services Inc. (THESI), Toronto Community Housing Corporation (TCHC)

Prime consultant: H. H. Angus & Associates, Toronto (Paul Isaac, P. Eng., Charlie Wang, Shan Ye, Naomi Littell)

Environmental subconsultant: Golder Associates


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