Climate-Friendly Buildings

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Bioclimatic Design

By David Kattenburg

For the first time in human history, on November 9, researchers at Hawaii’s Mauna Loa Observatory pegged the atmospheric concentration of heat-trapping carbon dioxide at 400 parts per million.

The number may mean little to the general public, but to Earth scientists tracking the relentless rise in atmospheric temperature linked to the burning of fossil fuels, that 400 ppm value has long been considered a potential “tipping point” in Earth’s climate equilibrium.

 

If 400 ppm carbon dioxide is a wakeup call, it rings loudly in northern hemispheric nations like Canada, where land predominates over ocean and climate warming is predicted to be the most extreme – well above the two degree cap governments will be negotiating at Paris COP-21 climate talks due to start on November 30. Dramatic shifts are already unfolding in the Canadian Rocky Mountains and Arctic, where ice pack and glaciers are melting at an alarming rate.

Andrew Weaver

Andrew Weaver

“It really is a game changer,” says Andrew Weaver, a climate modeler at the University of Victoria, in British Columbia, and a contributing author of the last four scientific assessments carried out by the UN Intergovernmental Panel on Climate Change. Weaver is also Deputy Leader of the British Columbia Green Party, with a seat in the provincial legislature.

“Where we’re headed is to warming on the order of three, four degrees,” Weaver says. “When we start to talk about four degree warming, you’re talking about staggering levels of ecosystems committed to extinction. How does a city like New York survive? You start to have storm surges on higher sea level that have events like Sandy happening every year! It becomes a bit of an issue.”

David Schindler, retired Killam Memorial Professor of Ecology at the University of Alberta, in Edmonton, is worried about Canada’s freshwater resources. Schindler founded Canada’s renowned Experimental Lakes Area, in Ontario, where the impact of pollutants and atmospheric warming were studied in situ. He looks back on past studies as an early climate warning bell.

David Schindler

David Schindler

“If I would have predicted … what we were going to see this summer, I would have been right on – fire in the basins; more chemical inputs from the fire; drought; declining stream flows; changes in chemistry, which we haven’t seen here because nobody has studied it, but there were some important chemical changes as well.”

Studies Schindler has contributed to predict that over ninety percent of interior BC and Rocky Mountain glaciers will be gone by 2100, reducing summer river flows in Canada’s interior. This, and heat-induced acceleration of the water cycle and parallel rise in extreme weather events will make Canada’s freshwater resources much less dependable in years to come.

In the Canadian province of Manitoba, where lakes and rivers abound, the public energy utility, Manitoba Hydro, is preparing for the worst. Three quarters of a million Manitobans rely on electricity Manitoba Hydro generates within the Nelson and Churchill River basins. River flows stand to drop as Earth’s climate warms.

In response to the threat, Manitoba Hydro’s Power Smart program has managed demand – encouraging consumers to be as energy efficient as they can. In the early 2000s, with plans for new Winnipeg headquarters underway, Hydro decided to bring its energy efficiency campaign back home.

Tom Akerstream and Manitoba Hydro's prairie garden

Tom Akerstream and Manitoba Hydro’s prairie garden

The 22-story office tower, completed in 2009, is the most energy efficient in all of North America – the only building in Canada to receive Platinum certification under the Leadership in Energy and Environmental Design (LEED) program.

Manitoba Hydro architect Tom Akerstream describes Hydro’s new building as “bioclimatically responsive” – designed to cooperate with outside weather and climate, rather than altering it. The tower reduced the utility’s energy consumption by sixty percent – three times Canada’s current greenhouse gas reduction target.

Like Earth’s climate, Manitoba Hydro’s office tower is an integrated system. Heating and cooling are provided geothermally, through a network of pipes buried beneath the building. Heat is drawn from the ground in the winter, and injected back in the summer.

Inner window wall opens

Inner window wall opens

The building’s geothermal system is supplemented by passive solar exposure, maximized by an ingeniously designed, south-facing double wall – the outer one double glass-paned, the inner one single-paned. In the winter, both walls are closed, allowing air trapped between the two walls to heat under the sun. In the summer the outside windows are opened and the inner ones kept closed, so that the inside of the building doesn’t overheat. Winnipeg’s prevailing southerly winds get caught by a vertical baffle running up the double wall, directing wind through it, cooling the building.

Inside Manitoba Hydro’s new building, large water features humidify cold, dry air in the winter, and dehumidify air in the summer.

Lung of the building, with water feature

Lung of the building, with water feature

The most unusual feature of Manitoba Hydro’s groundbreaking building is its “solar chimney” – a multi-story shaft of glass projecting above the roof. As heated air within the chimney rises, it draws inside air like a straw, ventilating the building at no energy cost.

On top of it all, maximum solar exposure reduces the need for electric lighting, and passive air circulation provides excellent indoor air quality.

And on an outdoor balcony overlooking downtown Winnipeg, a prairie garden grows. In the summer, native grasses cool the office space below, slow storm water flow, and provide duck habitat. Bee hives are planned for next summer.

In a so-called “Three Degree World,” where carbon emissions must go down and energy efficiency up, buildings like Manitoba Hydro’s will be in demand. Buildings consume nearly half of the energy generated in North America, and account for forty percent of its CO2 emissions. Opportunities to make them more energy efficient are considered “low-hanging fruit.”

“I’m convinced if we put the same team together and built another tower, we’d be able to build it even that much better,” said Tom Akerstream. “You’re going to see some other building going up in North America that are going to hopefully surpass this building in the future. We have helped them with the design of their buildings.”

 

 

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