Calgary Courts Centre Atrium
December 1, 2010
By Canadian Consulting Engineer
The Calgary Courts Centre consists of two towers, joined by a 150-metre high open atrium. By joining the buildings this way, the designers found that the towers would expose less wall to the exterior, thus achieving energy savings.The...
The Calgary Courts Centre consists of two towers, joined by a 150-metre high open atrium. By joining the buildings this way, the designers found that the towers would expose less wall to the exterior, thus achieving energy savings.
The 150-metre atrium is believed to be the tallest atrium ever built in a cold climate. It provides a spectacular entry lobby and houses the elevators that serve the courtrooms and other facilities on the upper floors. The highest tower is 24 storeys, but because of the high floor heights in the courtrooms, it is equivalent to around 35 storeys high.
The challenge with such a tall atrium was dealing with the stack effect. Even with a tight building envelope, air would normally rush in at the main level and be drawn sharply up through the space. Tests showed that the force would be 1.5 inches static pressure, says Paul Elfner, P. Eng. of Hemisphere Engineering, who were the mechanical engineers. That’s equivalent to about 100 lbs. of force pushing on a 3 x 7 ft. door, i.e. “quite severe,” he says.
Hemisphere’s solution was to provide a system that keeps the main floor at a neutral or slightly positive air pressure. The equipment is similar to what they used in a high-containment laboratory on a previous project. It includes an equalizing tank and four high quality pressure sensors that measure the outdoor conditions. As well the ambient pressure on each floor is individually maintained through sensors and controls.
To minimize the stack effect further, the building has a highly efficient building envelope to prevent air infiltration. The envelope features triple-pane, argon-filled low-E glazing. Its high cost was offset by reducing the size of the boiler and chiller plants and eliminating perimeter hot water heating.
The atrium contributes to the overall HVAC system in various ways. For example, in summer warm air is vented out of the top, and in winter warm air along its south wall is redirected inside the building. Thanks to these and other measures, the building uses 50% less energy than an equivalent conventional building.
Client: Government of Alberta
Mechanical consultant: Hemisphere Engineering (Paul Elfner, P. Eng.)
Architects: Kasian (lead), NORR, Carlos Ott, Spillis Candela DMJM