Energy & Atmosphere
The Energy Efficiency category aims to reduce energy consumption, helping to reduce pollution caused by power generating plants. Energy efficient buildings also have lower operational costs.
The WCC’s exceptional mechanical and electrical systems are reducing energy use by 71% over the minimum requirement for energy efficient buildings, as determined by the Model National Energy Code for Buildings (MNECB). Measures used to achieve this reduction include:
1. Heating, ventilation and air conditioning (HVAC) system:
• The HVAC system is an “air-to-air” heat exchange system utilizing 55 fancoil units (evaporators), 4 branch circuit controllers (gas/liquid separators) and 8 roof top compressors. This system allows for both heating and cooling year round, rather than having to switch from one to the other in spring or fall. The heat pumps can run at partial load (at 10% energy use/capacity if less heat/cooling energy is needed), instead of full-on or full-off like a regular heating system.
• Heat is recovered from zones that are in the cooling mode and transferred to zones that require heating. For example, heat produced by cooling the IT room is transferred to 14 fancoil units and provides a large portion of the heating requirements to the lower east end during the winter.
• Excess heat in the refrigerant tubes (gas) is removed by heat recovery units in the mechanical room and transferred to a heat exchange system that provides all the hot water requirements for the WCC. Any remaining heat is compressed to liquid by the roof top units and returns to the branch circuit controllers.
• A recovery wheel (located in mechanical room) reclaims 60-80% of the conditioned temperatures that would otherwise be lost. In heating season, heat is removed from stale air that is to be exhausted from the building, and transferred to fresh air being drawn into the building. In the cooling season, this process is reversed, removing some heat from the incoming air and transferring it to the outgoing stale air. This system also allows the exchange of moisture to control humidity.
• The temperature of fresh air drawn into the building is moderated with the use of earth tubes and a solar wall, which are passive renewable energy systems. In the summer, two earth tubes take advantage of the earth’s cooler underground temperature. The tubes (50 m long, buried about 2.5 m underground) pre-cool the air by 10°C or more. In the winter, the solar wall (perforated blue panels) on the outer south side of the building absorbs heat from the sun, pre-heating the incoming air by 20°C or more.
• Fresh air is dispersed through high volume, low velocity air diffusers located throughout the building. Dampers in each diffuser adjust the local flow of fresh air in response to CO2 sensors that are installed at every air-handling system and in each zone of the building. These sensors help to save energy during unoccupied periods and provide sufficient ventilation during periods of high occupancy.
• The HVAC system has an automatic temperature setback so it is not heating/ cooling/ ventilating spaces at night or on weekends or holidays.
2. In conventional buildings, one of the greatest sources of wasted energy is from heat loss from a leaky building shell and non-optimal building orientation:
• The building is oriented along the east-west axis, which helps to prevent glare as well as to prevent one side of the building being too warm in the morning and the other side too warm in the afternoon. The north side of the building has the most glazing (glass) to allow for desired solar heat gain and daylight.
• The roof is a white, reflective roof to minimize the urban heat island effect and decrease summer cooling costs for the building.
• The roof has a shaded overhang to prevent glare from direct sunlight through the windows.
• The building shell is air-tight and is constructed from poured concrete with rigid insulation to achieve a high R-value (resistance to air loss) of R40 for the roof and R20 for the walls.
• Windows are triple glazed windows on the north side and double glazed winders on the south side to reduce heat transfer.
3. Lighting is one of the largest energy uses in modern offices:
• The lighting power density (amount of energy used to light a given area) is 15-20% less than a conventional office.
• Light fixtures are high efficiency T8 fixtures.
• Almost all the lighting is on occupancy sensors to only turn on lights when someone is in that area or room.
• Daylighting sensors dim lights when there is sufficient natural light.
• The building’s design and orientation maximizes daylighting so that 75% of spaces have access to daylight.
4. Fanshawe Dam is a flood control dam, but a small hydroelectric generating plant is an ancillary benefit that provides a source of renewable energy for the WCC. The plant produces 2,860 Mwh/year, which is enough to power approximately 300 households. This power was used by multiple buildings including the old admin building, offices on the dam, portables, rowing club building, and a small former residence. The old admin building consumed an estimated 200,000 Kwh/year. Excess generated energy is sold to the grid. When the hydroelectric plant is off line for maintenance, electricity is bought from London Hydro.