Building Features
Passive Versus Active
To achieve a high level of energy efficiency while maintaining occupant comfort, Manitoba Hydro Place maximizes the use of passive energy technologies while minimizing the use of active energy systems.
Passive systems (i.e. south-facing winter gardens, natural daylighting, and the solar chimney) take advantage of the environment and natural processes to reduce energy usage. Active systems (i.e. dimmable, programmable fluorescent lighting) help maximize the effectiveness of passive systems and supplement them as required.
Some of the energy efficient measures and systems include:
- high ceilings help maximize natural lighting;
- exterior walls made of low-iron glass for maximum solar gain;
- double walls buffer against the extreme climate;
- operable exterior wall vents;
- operable interior windows;
- automated solar shading;
- south-facing winter gardens precondition air entering the building;
- geothermal heating and cooling system;
- solar chimney provides ventilation and air movement throughout the structure;
- recovered heat energy from exhaust air used to heat underground parkade and preheat air entering building;
- raised floors with a displacement ventilation system;
- T-5 high output lighting, with occupancy and light sensors on each fixture;
- advanced computer-based Building Management System (BMS) to coordinate operation of energy management and building systems;
- green roofs;
- building location and design selected to maximize use of solar energy.
Heating, Cooling, and Ventilation
In a typical office tower, heating, ventilating, and air conditioning (HVAC) is a combined system, where the ventilation air is warmed or cooled to the desired interior temperature. A large portion of the ventilation air is often recirculated through the building to save energy, which may result in a stale, stuffy environment.
To maintain a high quality, productive workspace while achieving maximum energy efficiency, the design of Manitoba Hydro Place splits HVAC into 2 distinct functions:
- Heating and cooling, provided primarily by the geothermal system;
- The geothermal system consists of 280 wells located under the building. Each well is almost 121 m (396 ft) deep and contains a closed loop of glycol. In winter, heat in the ground warms the glycol. The heat in the glycol is extracted and transferred to water, which is circulated through pipes embedded in the building's concrete slabs. The slabs – that are exposed to form the ceiling of each floor – are heated by the water. The heat radiates down from the slabs into the workspaces.
- In summer, the system is reversed to cool the building, with heat extracted from the building transferred into the ground.
- In total, over 228,600 m (750,000 ft) of pipe runs through the slabs. The slabs have a high thermal mass and provide radiant temperature control.
- The geothermal system used at Manitoba Hydro Place is the largest geothermal system installed in Manitoba. Over the course of a typical year, it is a "net zero" energy exchange system. This means that heat energy extracted from the ground during the winter months is replaced during the summer months, making the system fully sustainable over the long term.
- Ventilation, provided by a combination of the solar chimney, winter gardens, and overall building design.
- Fresh air is drawn into one of the three 6-storey or the single 2-storey atria (winter gardens) on the south side of the building. Water features in each winter garden provide humidification/ dehumidification of the fresh air, while waste heat recovered from the exhaust air and natural solar energy warm the fresh air.
- The south winter gardens act as lungs, providing preconditioned fresh air to the building via the raised floor system.
- This preconditioned air enters workspaces through vents in the raised floors. Occupants and other sources of heat will cause the air to rise toward the ceiling. This system supplies the office space with 100 per cent fresh air, 24 hours a day, year round, unlike a conventional building where air is recirculated.
- The air rises to the ceiling and flows to the north end of the building, where it is exhausted passively by the solar chimney.
- Natural ventilation minimizes the need for a forced air mechanical circulation system.
- In the intermediate seasons (spring and fall), the mechanical ventilation systems will be turned off and the building will be ventilated by opening windows.
Solar Chimney
The 115-metre-high column rises above the top of the building on the north side. It is key to the passive ventilation system of Manitoba Hydro Place, relying on the natural "stack effect" of a chimney to create a draw of air out of the building.
In winter, exhaust air is drawn to the bottom of the solar chimney. Heat recovered from this exhaust air is used to warm the parkade and to preheat the incoming cold air in the south winter gardens. In summer months, warm air is exhausted directly out of the solar chimney.
Humidification/Dehumidification
Six large water features provide more than just decoration in the building. Four of the water features are located in the building's south winter gardens, and 3 are an impressive 22 m (72 ft) tall with water flowing down 280 mylar cables. The water is collected at the bottom of each feature for reuse.
The water features humidify or dehumidify the air in the building depending on the season. During the summer months, when the water is colder than the air surrounding it, the water absorbs additional moisture, lowering the humidity of air entering the workspaces. In winter, the water is warmer than the air in the winter gardens. This allows moisture to evaporate more easily into the air, providing humidification.
Two smaller water features regulate humidity in the main gallery. These features have water cascading down a granite surface, replicating the spillway of a hydroelectric generating station.
Efficient and Healthy for People
The design of Manitoba Hydro Place is proof that an extremely energy efficient and sustainable building can also be one that provides an unsurpassed work environment for its occupants. Staff moving to 360 Portage Avenue will enjoy one of the most healthy, vibrant, and productive workspaces in the world, while also contributing to the revitalization of downtown Winnipeg.
The design of the building is where it all begins. The expansive glass curtain walls on the east and west facades provide an airy workspace full of natural daylight. Operable windows on the interior curtain wall, combined with exterior wall vents controlled by the Building Management System, provide employees with a great degree of control for their own ventilation requirements during spring and fall.
Even during winter and summer, the building is supplied with 100 per cent fresh air, 24 hours a day, 7 days a week, improving productivity and health. State-of-the-art workstations and ample meeting spaces ensure that employees are able to both collaborate and work in isolation as required.
Stairwells linking floors in the winter gardens provide a degree of vertical connectivity, creating neighbourhoods of work that contribute to enhanced employee productivity. And the fact that more divisions and departments are now being brought together in one location will also reduce travel time to meetings and help lower greenhouse gas emissions.
The end result? Higher productivity, lower costs, environmental benefits, and better service for our customers.
