Manitoba Hydro Place - Energy Efficient Design

Energy Efficient Design

To meet its initial design target, that of a sustainable, energy-efficient building, Manitoba Hydro Place (MHP) was developed using an Integrated Design Process to optimize the building's massing, orientation and exposed thermal mass and to use digital analysis and computerized building management systems to increase its efficiency. MHP integrates passive elements (e.g., the south-facing winter gardens, natural daylighting, and the solar chimney) as well as active systems (e.g., dimmable, programmable fluorescent lighting and a computer-operated building management system).

See: Conceptual diagram of building systems at MHP

Key specifics of the design include siting of the building to take advantage of prevailing winds and solar gain, minimizing north-facing surface area, using the building's south-facing atria to provide and precondition the building's constant fresh-air supply and using several 24-meter-tall waterfalls to humidify and dehumidify the fresh air intake. Green roofs at the base of the building use plants to reduce stormwater runoff and minimize the building's heat-island effect, including such native prairie plants as sweet grass.

The design uses the building's concrete thermal mass to mitigate extreme temperature swings and integrate radiant heating and cooling systems, with a solar chimney to provide 100% fresh air by moving exhaust air to the bottom of the chimney to combine with the atria's preconditioned air and preheat incoming cold air to within room temperature, and employing geothermal technology via a closed loop system of 280 boreholes, six inches in diameter (variously reported as five inches in diameter), 400 feet deep, located between elements of the foundation. The geo-thermal boreholes are filled with tubing carrying glycol, which extracts heat from the building in warmer months while warming the thermal mass of the floor slabs radiantly in colder months. Heat pumps and exchangers maximize the system's efficiency, providing conditioned water that is then circulated in tubes in the exposed ceiling slabs, providing 100% of the mechanical temperature conditioning.

MHB features a high performance building envelope with a glass skin that is effectively triple-glazed — where the interior layer is single-glazed and separated from the double-glazed exterior layer by a one meter wide buffer zone. Windows at the east and west include operable sashes of both motorized, centrally controlled panels in the outer glazing and manually operated panels at the inner glazing as — well as shading located in the interstitial space. The floor plan shapes themselves (also known as floorplates) of MHP are shallow, with a distance of 11 meters from the face of the building to its interior core, facilitating natural daylighting.

Other systems integral to the design include high ceilings to maximize natural lighting, exterior walls of low-iron glass for maximum solar gain, automated solar shading, raised floors with a displacement ventilation system, high-output lighting with occupancy and light sensors on each fixture, a computer-based building management system to coordinate operation of energy management and building systems as well as a group of green roofs at the building's podium.

To achieve personal comfort levels, users have access to the operable elements of the façade and receives natural lighting 80% of normal office hours. In addition to the operable sashes, users can control their immediate environment via task lighting, shading devices and user-operable floor grilles.

Incidental to the building design itself, another idea behind MHP was indirect energy savings the project would facilitate by combining 15 disparate company entities in a single downtown location. Before MHP opened, 95 percent of the employees commuted to work via automobile. After working at the new building for less than half a year, 50% of commuters were using forms of transportation other than the automobile.