Heating, cooling and ventilation
Geothermal well field
UOIT is home to Canada's largest geothermal system (and the second largest in North America), a 1,500-ton Borehole Thermal Energy Storage System (BTESS) that sits hidden beneath the 7,500 square-metre quad at the centre of the complex. The installation is made up of more than 370 bore holes (180 metres deep), which are used to heat and cool the campus buildings. Water circulates through the underground network (150 km of polypropylene piping). In the winter, the geothermal system takes heat from the earth and carries it to the buildings. In the summer, the same system removes heat from the buildings and disperses it into the ground. The innovative system links each building to a central heating, ventilation and air-conditioning (HVAC) plant.
UOIT has a central plant that provides a cooling and heating system for the entire north Oshawa location. The efficient HVAC solutions, integrated with the custom-designed geothermal systems, deliver 50 per cent better energy efficiency than Model National Energy Code for Buildings (MNECB) requirements. Supplemental heat is provided by three of six condensing boilers that are more than 95 per cent efficient. The boilders provide heat for entrances, hallways and other areas where doors are frequently opened and closed, and where heat doesn’t reach easily. Chillers, used to create air conditioning, use magnetic induction in a centrifugal compressor system. A series of heat exchangers, with a 30 per cent glycol mix, prevents the coils from freezing in the winter. Classrooms are equipped with an energy recovery wheel located just below the rooftop to preheat the outside air with heat recovered (71.7 per cent effectiveness) from exhaust air. In the case of laboratories, where air contamination is a major concern, a loop system is used to reclaim waste heat.
A ground-source heat exchanger is used as the primary source for heating and cooling at the central plant. Thermal energy produced at the plant is used to heat existing and new buildings on the UOIT and Durham College joint campus, while the electricity produced is used to displace electrical load from the provincial supply grid.
The university campus has a relatively high occupancy load, but it is also a transient occupancy schedule. The mechanical systems at UOIT have been designed to efficiently meet the building ventilation requirements, while responding to the variable occupancy levels of the buildings spaces. To capture free cooling opportunities, 100 per cent outdoor ventilation is available to all spaces of the buildings; that means no mechanical cooling is required, since ambient air can provide the required conditioning. To minimize ventilation heating as well as ventilation air cooling, three thermal energy recovery wheels have been installed in the university’s ventilation system. These wheels capture the sensible and latent heat of air being exhausted from the buildings. The mechanical systems are all variable air volume systems, where the volume is controlled by variable frequency drives on the supply fan motors. Carbon dioxide sensors are used to implement a demand ventilation strategy, controlling the ventilation supplied to the space based upon its occupancy.
Building automation systems
The facilities are all operated with computerized comprehensive building automation systems. All incoming electrical feeds are monitored with electronic metering so that the ongoing building operation can be optimized. Centralized computer control systems turn off lights in rooms when they’re unoccupied using occupancy sensors. They also monitor air temperatures and automatically oversee other aspects of the interior space. CO2 monitors assess air quality and control the outside air use.
Walls, roofs and insulation
UOIT buildings are designed with high levels of insulation in the outer envelope. The roof has an R-value of 30, the walls have an R-value of 24, and the windows have an R-value of 9 with thermally broken frames and no thermal bridging. Penthouse walls were all insulated to R-20 to avoid waste heat losses from the mechanical spaces. For a substantial capital cost saving for the perimeter heating system, the university buildings have a high-efficiency glazing system, allowing for a complete neutralisation of the perimeter skin of the building. To significantly reduce the yearly energy consumption of the building, our exposed concrete structure provides thermal massing. The sod roofing will reduce heat losses in the summer and solar gain in the summer.
The building envelopes were all designed with two types of windows. The first is the high-performance Heat Mirror window with a centre of glass thermal resistance matching that of 25-millimetre polystyrene. Windows are super-high efficiency, with special thermal properties to maximize the use of passive solar heat metal oxide-coated window glazing that blocks 99.5 per cent of UV rays. The other type of window used is Softcoat LoE². These windows provide the highest level of comfort and energy savings year-round. They block up to 84 percent of the sun's harmful ultraviolet rays and deliver a remarkable 96 percent performance improvement in winter nighttime insulation (R-value) compared to non-coated air-filled insulating glass. The coating is virtually invisible to the eye – it is just like looking through clear glass. Controlling solar gain not only saves energy during the air-conditioning season, but it also improves the comfort and livability of sunny rooms during the spring and fall when the cooling system isn't normally used.
Four buildings are constructed with extensive green roofs (total of 40 square metres). Grass and soil on rooftops aid drainage, retain heat and improve air quality. Roof runoff water is collected in an underground cistern with a capacity of 250,000 litres. This water is then used for irrigation and flushing within the Business and Information Technology Building, reducing the university's fresh water consumption of treated water from municipal sources.
Solar shading, daylight and lighting
Each building is designed around a central atrium that provides natural light through all the floors. Orientation-specific solar shading is used to reduce solar gain. The lighting was designed with T8 luminaires with dimming electronic ballasts and comprehensive occupancy sensor coverage in the new buildings. Light levels are set at optimal levels and controlled by photo sensors in the spaces, and lighting energy is eliminated when the spaces are unoccupied.