Canada’s Largest Net-Zero Energy Institutional Building Produces More Electricity Than It Uses
Mohawk College’s Joyce Centre for Partnership & Innovation in Hamilton, Ontario, is Canada’s largest net-zero energy institutional facility and the first in the country to be awarded Zero Carbon Building – Design and Performance certification from the Canada Green Building Council, positioning it as a hub for carbon-neutral technologies and operations. A joint venture by mcCallumSather and B+H Architects, the L-shaped $54 million, 96,000-sqft edifice comprising lecture halls, classrooms, laboratories, a library, student collaboration rooms and the offices of the Centre for Climate Change Management at Mohawk contributes to the World Green Building Council’s “Advancing Net Zero” initiative that aims to ensure that all buildings are net-zero carbon by 2050 and all new buildings are net-zero carbon by 2030. Anthony Cupido, Research Chair of Sustainability at Mohawk College, says, “We attempted to differentiate ourselves from all the other applications to the Strategic Infrastructure Fund for post-secondary institutions in Canada to improve their infrastructure by detailing a request for a unique (at the time) and bold net-zero energy facility. The College was providing leadership with an innovative design that would demonstrate commitment to a low-carbon future and aggressive Energy Use Intensity targets.”
Generating 100 % of the energy required to power the facility, the total capacity of the PV system installed on the Joyce Centre itself and on adjacent campus buildings is 550 kWp, and the net-zero (or rather, net-positive) energy goal was achieved. Energy production from April 2019 to April 2020 was measured at 653,633 kWh, and consumption at 465,135 kWh. On-site energy generation significantly outperformed what was modeled, with the photovoltaics producing 10 % more energy than anticipated. While the target was for generation to meet consumption, generation exceeded consumption by 40 %, which will have a direct impact on reducing the carbon payback timeline, greatly lessening the original estimation of 27 years to reach zero carbon while accounting for embodied carbon. Typically, buildings of this type are 230 to 300 ekWh/m2, but the energy budget target here was 75, and the final “as-built” energy model showed an improvement to 73 ekWh/m2. All extra power from the solar panels is exported to other campus buildings. In 2021, the Joyce Centre produced 665,582 kWh of electricity and used 376,853 kWh, a surplus of 288,729 kWh.
Necessary to satisfying extreme levels of hyper-efficiency, establishing an energy budget at the outset of the project represented a fundamental shift in the design approach. Joanne McCallum, CEO, Executive Architect and Principal in Charge at mcCallumSather, explains, “The energy budget became a driver, not a consequence, of design decisions and an equal priority to the stringent financial budget. All design decisions revolved around meeting these targets, but without sacrificing the high quality of student experience essential to the success of this institution.” The environmental technologies include: a high-performance building envelope consisting of triple-glazing and insulated pre-cast sandwich panels to maximise heating and cooling and natural light, a green roof with extensive planted areas, 28 geothermal wells, a variable refrigerant flow heat pump system, a dedicated outdoor air ventilation system, illumination and occupancy sensor-controlled LED lighting, high-efficiency plumbing fixtures and extensive measurement and verification protocols and infrastructure. Far surpassing the building air tightness target of 2 lps/m2, testing revealed it to be 0.545 lps/m2 – 73 % better than projected.
Lisa Bate, Principal in Charge at B+H Architects, comments, “The Joyce Centre pushes the practice of architecture to look not just at how we build a space, but also the ways we interact with it, exploring the unseen connections between building and user, client and designer – a space where commitment, education, technology and the environment converge to create a living lab for sustainable learning and innovation.” Marking a cultural shift in occupant behavior from open energy consumption to personal accountability, the facility makes users aware of the energy they consume and demands a change in habits, such as charging laptops and mobile phones at home instead of plugging into the grid continuously. Learning is not limited to the labs. Students have full access to all seven levels – from the basement mechanics to the green roof and solar panels – for hands-on learning on how to operate and monitor a zero-carbon building, able to observe, in real-time, the temperature, humidity, ventilation rates, thermal distribution, lighting performance and other key building metrics. Mohawk College student, Rutul Bhavsar, relates, “My fellow students have worked on projects leveraging the capabilities of the building, which have given them an important learning opportunity from a data analytics and renewable energy perspective, as well as a research and work environment to prepare them for future jobs.”
The photovoltaic array is set on cantilevered rooftop “wings” supported by unusual structural steel trees that visibly demonstrate engineering principles. Instead of hiding away the solar panels, they are prominently displayed as a central design feature, allowing students to learn about solar energy. Bate discloses, “One of the most distinct aspects of the building is its emphasis on celebrating its sustainable design features rather than obscuring them.” The bulk of the building’s embodied carbon is contained within its structure, largely concrete and steel. The steel was sourced from local suppliers, such as Walters Steel, and has a high recycled content, while the concrete mix incorporated higher than normal Supplementary Cementing Materials, specifically slag. For the foam insulation used in the insulated pre-cast panels, roofs and some of the detailing addressing thermal bridging, low GHG blowing agents were specified rather than the usual hydrocarbon-based blowing agents. A major carbon-reducing objective of the design is potable water use reduction via ultra-low flush urinals, low flow faucets and rooftop rainwater harvesting (228,000 liters) for toilet flushing and irrigation needs.
Bhavsar remarks, “What impressed me the most about the Joyce Centre is the thought that goes into picking the appropriate sizes of electrical and mechanical equipment for the design and purpose of the building. Every detail counts since minor design changes and incorrect operational assumptions can have a significant impact on overall performance. For example, unplanned occupancy levels can result in lower building performance and higher capital and operating costs. Institutional buildings have occupancy and energy consumption patterns that vary significantly throughout the seasons and academic calendar, and that are likely to change over the years. Although it is a difficult task to consider all these variables during the design phase, the work doesn’t end once a building has been built.”
Concerning the trade-offs of high energy-saving targets, Kevin Van Hartingsveldt, Project Manager at mcCallumSather, states, “No compromise to the design principles was necessary, but it was critical that the design be informed by the engineering. The massing, façade treatment and HVAC design had to be established via data-driven design, while balancing many competing priorities such as schedule and budget. Accordingly, there were some design elements that we had to scale back, but the final product is incredibly aligned to the schematic design.” For example, interior finishes and glazing had to be carefully considered and regularly revisited to ensure the extent and product selections were appropriate. The building exterior had to be cut back, most notably the number of elevated structural decks above the roofs, which impacted the distribution of photovoltaic panels. The original design also included vertical sun shades integrated into the curtain wall system. Anomalies have been observed in the seasonal performance of the geothermal system, which had been factored in. It was expected that in the first year, all building systems would perform atypically as the facility settles in, learns the demand loads and adjusts to the ground temperature over the long term.
Cupido believes that the Joyce Centre can serve as a model for sustainable practices for other educational institutions and change industry standards, saying, “The Joyce Centre has been visited by thousands of guests from all over the world during the past couple of years. As such, governmental policies and practices are being established or already in place to require low- or zero-carbon buildings in their local municipalities. Vancouver and Toronto are leading the way on this with changes to their local building code requirements.” The institution has become a demonstration site for industry partners looking to adopt zero-carbon technologies into commercial, industrial and residential buildings. Bate concludes, “The most important aspect of this project is to demonstrate that the technology exists today to design and construct affordable, exceptionally high-performing net-zero carbon enclosures to meet the UN’s Sustainable Development Goals (SDG) without sacrificing design or esthetic. Through the right balance of innovation, materials and systems, we can design truly sustainable environments that can be replicated and repeated to achieve future SDG targets. Sustainability and design are no longer mutually exclusive, and the Joyce Centre is emblematic of this paradigm shift.”