The Astute Architect

Is this the most energy-efficient office building?

Posting in Architecture

In a guest column, former Architectural Record editor Charles Linn takes a closer look at the tech behind Manitoba Hydro Place, a new building in Canada that sips energy.

C.C. Sullivan has the week off.

A recent announcement that Manitoba Hydro Place, an office building in Winnipeg, had earned a LEED Platinum rating from the Canadian Green Building Council wasn’t a great surprise -- Platinum ratings seem far too common these days. It was the fine print that caught my eye: according to Manitoba Hydro, the utility company that owns and operates MHP, the structure is consuming 70 percent less energy than an equivalently sized and located base-case building built to the current energy code. That saves about CAD$500,000 annually.

Astonishing. A 70-percent reduction can usually only be done with low energy-demand structures built in temperate climates -- say a park visitors center, or your typical billionaire’s doomsday compound deep underground. But MHP is a 22-story office building that occupies a square block in a town where the average temperature in January is -7 degrees Fahrenheit (though lows of -30 degrees are not unheard of, nor are highs of 90 degrees). If an office building can cut even 25 percent of its energy consumption, it usually generates a blizzard of press, particularly if that figure includes plug loads (which MHP's figure does).

How did KPMB Architects, Smith Carter and consultants Transsolar KlimaEngineering do it? For starters, they used a comprehensive climate analysis and computational fluid dynamics to optimize the building's geometry.

The structure also has a designers' wish list of energy saving technologies. For example, it employs 280 geothermal wells that heat and cool massive concrete radiant slabs. Its all-glass east and west elevations fly in the face of conventional wisdom that glass should be minimized in climates with temperature extremes. It also boasts double-walled facades with automatic blinds that reflect the sun, and over 440 windows that open automatically to keep the building from overheating.

A massive solar chimney aids natural ventilation through convection. Fresh air drawn into atriums containing hundreds of vertical mylar ribbons that conduct water streams humidify the building. All of this, and much more, is controlled by a building management system that monitors energy use and takes guesswork out of operating the building. It receives input from 25,000 sensors and two weather stations.

Is this kind of technology out of the reach of most office-building owners? Yes. But if you look at it from a first-cost basis, mechanical floors, fan rooms, and other mechanical equipment is significantly downsized or eliminated. Dropped ceilings and ductwork? Gone. Floor-to-floor heights? Significantly reduced.

With energy codes drastically pushing down the amount of energy that can be consumed in buildings, companies like Manitoba Hydro and firms like KPMB and Transsolar are showing how it's done. And they freely share what they've accomplished: Manitoba Hydro already conducts tours, and it has announced that it will publish the structure's energy performance data this fall. Building owners seldom release this information, often because their buildings aren't performing as well as predicted.

Charles Linn

Charles Linn, FAIA, is an architect and journalist who has spent the past 26 years writing about architectural design, practice, and technology. He was formerly deputy editor of Architectural Record, and editor-in-chief of Architectural Lighting, which he started in 1986. He is about to embark on a new career as communications director for the University of Kansas' School of Architecture, Design and Planning.