Energy modeling becoming a requirement

Energy modeling is becoming a standard part of building design according to Brian Tysoe, P.Eng., national manager of energy modeling and building simulation services with MCW Consultants. Tysoe spoke at Construct Canada in Toronto on November 29 in a session entitled “Beyond Compliance: Energy Modeling and Building Simulation.”

LEED and building code changes are driving the need to have energy modeling, Tysoe said. However, he has reservations about whether much of the modeling is actually reducing energy use, since most of it is done just for compliance purposes and there is little or no official follow-up to see whether a building lives up to the models.

Energy modeling goes back to the 1990s, said Tysoe, with the advent of the federal Commercial Buildings Initiative (CBIP) Program. It provided funds for buildings that promised to be 25% more energy efficient than the Model National Energy Code for Buildings. In order to qualify, of course, the building’s proponents needed to provide an energy model.

In the last eight years, he continued, LEED (Leadership in Energy and Environmental Design) has been driving an increasing use of energy modeling since projects need it to acquire points for certification.

Another driver has been the adoption of P3-type projects where the contractor will be operating a building for 30 years and so has to project what the utility bills are likely to be. Tysoe’s own company, MCW, is involved in energy contracting services, which means they also needed to be able to predict energy savings.

All the above roads to energy modeling have been voluntary, but the “big turning point” came in Toronto in 2010 when energy models became mandatory for approval of buildings in Toronto under its Green Building Standard, said Tysoe. And since January this year, the Ontario Building Code has introduced energy requirements. The OBC rules can either be met by following a prescriptive method, or by showing compliance with an energy model.

Today, then, he suggested, “We are at a point in Ontario where energy modeling is mainstream.” Where modeling used to be for high performance buildings only, he said, it is now included in building codes.

The question, though, said Tysoe, is to ask what the energy modeling is really being useful for.  “In my opinion it is used largely  for compliance,” he said. There are no official checks and balances to ensure that the energy model coincides with the actual building’s performance.

The “big push now is for greater verification,” he said. Monitoring requires installing meters in a building. Today we can meter even down to the level of individual control valves on the HVAC equipment.

On one hand energy models today can be too simplistic, Tysoe suggested. On the other hand, energy modeling at the site development stage can be very useful. He showed a scheme developed on the Toronto waterfront where a massing study was done of a point tower vs. a bar tower to see how the prevailing winds (speed and direction) would affect the building’s energy use. He said you could show big energy savings by playing with the building form, possibly more than you would see by “tweaking the mechanical-electrical systems later.” He also showed studies done for a university in Saudi Arabia looking at the effects of having different amounts of clerestorey glass on the building’s energy consumption.