Issue link: http://digital.canadawide.com/i/218643
Design With A Conscience Are misinformation and budgetary constraints slowing the progress of green building design? by Godfrey Budd W ith buildings consuming roughly 40 per cent of overall energy worldwide, ongoing energy use is the single greatest environmental impact of a building. Despite concerns around energy efficiency, electricity consumption in commercial buildings doubled between 1980 and 2000, according to Vladimir Mikler, a principal at the Integral Group who presented his findings at SustainaBUILD Vancouver. One of the obstacles to better energy performance of buildings may stem from the uncertainty around the targets themselves. In North America, using ASHRAE 90.1 in the U.S. and MNECB in Canada, energy performance is a moving target with relative comparisons to an unclear baseline and is measured in non-energy units, according to Mikler. On the other hand, he says, the European Union provides a clear and measurable target for energy intensity expressed in kWh per square metre per year. Mikler advocates a climate-adapted approach to building design that has an array of passive features. Some are geared to protect the interior from the external environment and include a small glazing ratio, a strategy for thermal mass and good use of masonry on the south, east and west exposures. Daylighting, buffer space, solar shading and cooling by natural ventilation are passive measures he recommends. Regarding the HVAC system, Mikler says that this should have separate heating and cooling systems. "You should have a radiant heating and cooling system," he says. "Radiant heating operates at a much lower temperature than conventional heating. Also, use outdoor ventilation. In the peaks of winter and summer, this is the time to use mechanical ventilation as you need to temper the air." Vancouverites in parts of the city's central districts could soon be saving on HVAC costs. This is if a project involving the creative exploitation of a Green building design p14-23Green Building.indd 15 Photographed from the Level 54 atrium space: The Bow's cavity between the inner and outer facade – considered to be the most dramatic of the four atrium spaces because of the skylight. Photos: Nigel Young / Foster + Partners. potential heating and cooling source in the form of a water pipe that circles the city core actually goes ahead. The pipe in question was originally designed as a firefighting resource but has never been used. The temperature of the water inside it ranges from about five to 15 degrees Celsius and the pipe has been proposed as an ambient temperature loop. "It would work as a low-grade energy source and heat sink. There are commercial buildings in the north end that need cooling even in winter. More in the south, there are residential buildings that need heat mostly and are heating dominated. The loop system would be complementary. The buildings that need cooling would reject the heat and the residential buildings would harvest the surplus. You would need heat pump technology at both ends to make this work," explains Mikler. The pipe is 600 mm in diameter and runs a five-kilometre circuit. Mikler says it could be linked to several prominent downtown buildings including Canada Place and the city's new convention centre. Effective design strategies for reducing energy consumption don't have to involve a step-change upward in capital costs. Some measures and products come with a hefty price tag but with negligible improvement in performance. "A lot of triple glazing is a waste of money. Sometimes the frames are the weak link," says George Steeves, president of Sterling Cooper Consultants Inc. He refers to a double-glazed product with a U value of 0.25 at the centre of the glass that goes to a less impressive overall U value of 0.38 when the frame is added to the mix. With some plant re-tooling and a resulting upgrade to the frames, Steeves says, the overall U value improves to 0.32. Another inexpensive measure involves the recovery of heat from the transformer rooms of a residential december 2013 /15 13-11-15 3:38 PM