April 30, 2008

COBALT ENGINEERING

The three-storey Regent College building is located largely below ground and takes advantage of natural lighting, while a local aquifer provides radiant cooling. A specially-designed tower helps to draw air through the building, creating natural ventilation.

Building Envelope

Net zero approach vital to energy conservation

PETER KENTER

correspondent

When choosing a building envelope or façade, designers can work with or against the surrounding environment.

The initial choices in designing the building envelope determine the degree to which mechanical systems and excess energy are required to facilitate human comfort, said Albert Bicol, a partner with Cobalt Engineering, a design company with offices in British Columbia and Toronto.

Bicol said that half the world’s energy is expended on building lighting, heating, ventilating and air conditioning and 65 per cent of that energy is lost in transmission.

A net zero approach to building design eliminates dependence on outside energy sources while optimizing comfort.

“The main goal in net zero design is to look at reducing or eliminating electrical and mechanical systems as much as possible,” Bicol said.

“The idea is to reduce the load of the building itself. We shouldn’t be relying on high-tech solutions, but low-tech and passive solutions that will future-proof the buildings we put up today.”

Traditionally, building designers look at the climate where a building project is to be located.

“By studying micro-climate data in the immediate vicinity of the building, we get much more accurate data than if we relied on data collected at an airport 100 miles away,” he said.

“We can look at the way local plants and animals adapt to the environment and mimic what they’ve done. We can look at the way sunlight strikes the building. In Vancouver, wind blows in from the inlet and accelerates above buildings to a degree that we can take advantage of wind turbines, but the airport data doesn’t show that wind acceleration — we had to measure that ourselves.”

Human comfort also relies more on radiant energy from sources such as the sun, than convection systems, for example.

“We don’t have an energy problem,” said Bicol.

“We’re not taking advantage of the opportunities to use the energy all around us.”

Informed choices in glazing, building fabric and envelope type can help to work with environmental factors to take advantage of low quality energy. If solar energy provides human comfort, then buildings should be designed to take advantage of it, rather than converting it to electricity.

“Photovoltaic panels are perhaps only 20 per cent efficient in transforming the lowest quality of energy — sunlight — into the highest quality of energy — electricity,” he said.

Buildings in Vancouver generally provide large windows to expose occupants to a western view.

“We’re giving them a western view and by afternoon all of the blinds are down,” Bicol said.

“We should be designing a façade that gives occupants an adequate view but doesn’t let so much light in. The south façades should be provided with shading while the north side should have mullions. We should be designing the building façade to take advantage of overhangs and shading and natural vegetation.”

Cobalt Engineering provided the mechanical engineering for the new Regent College Library in Vancouver to use low-grade energy. The three-storey building is located largely below ground and takes advantage of natural lighting, while a local aquifer provides radiant cooling.

A specially-designed tower helps to draw air through the building, creating natural ventilation.

“We had initially designed the system to use solar panels to create the hot water for radiant heating,” Bicol said.

A high-efficiency boiler was used instead.

“While we were aiming for a net zero building, we still have a building that heats, cools and ventilates on one kilowatt per hour,” he said.

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