ENERGY AND ENVIRONMENT
Currently, buildings account for approximately one third of Vancouver’s energy consumption, with most of that energy being derived from fossil fuels, such as natural gas. By reducing energy use in our buildings, especially energy from fossil fuels, we can significantly reduce our contribution to global greenhouse gas emissions and contribute to climate protection (Bayley, 2010).
The SEFC Net Zero building meets its net zero targets through a three-pronged approach of energy efficient design, occupant engagement and energy generation. Energy efficient design is achieved through passive design strategies, which include: optimizing building orientation, maximizing insulation, appropriate placement of thermal mass, and optimizing daylight and natural ventilation opportunities. These passive design strategies minimize mechanical heating, cooling and ventilation needs.
The utilization of an enhanced envelope with exterior walls that are insulated on the outside, thus preventing thermal breaks, and the installation of triple-pane windows are other design features that enhance the passive design approach. The insulation values of the windows used are, for example, approximately four-times superior to those of single pane windows. Thermal mass materials that absorb and release energy slowly, such as concrete, are used to regulate the interior temperature. Insulation of balconies and outdoor walkways reduces thermal bridging.
In addition, air is expelled from suites to the roof by an innovative vertical ventilation shaft that is kept at negative pressure. The plan maximizes cross-ventilation by ensuring a large number of suites have two external walls so that air can travel from one side of the suite to the other more easily. The designers chose to locate corridors and stairs on the outside perimeter of the building so that these do not have to be ventilated and heated mechanically, thereby saving energy. Throughout the project, the emphasis was put on high quality materials and smart design to optimize long-term building performance (Bayley, 2010).
Educating building occupants about the net zero objectives, and soliciting their participation in reducing resource consumption, are additional key strategies that support the passive design approach. For this purpose, meters have been installed in each unit, allowing occupants to monitor water, heat and electricity use. It is projected that this will reduce energy consumption by 15-20 percent.
Energy efficient technologies, such as LED lighting, energy efficient appliances, radiant heating, heat recovery and renewable energy sources such as thermal solar also contribute to achieving net zero targets.
To reach net zero energy use, the Net Zero building must generate its own energy. It does this by taking advantage of its location in a dense urban setting. The Net Zero building is located above a large grocery store in a mixed-use neighbourhood. This enables the use of a heat recovery system, which employs waste heat from the refrigeration system of the grocery store to provide space heating for the building. A 45 square-metre solar thermal system located on the roof of the Net Zero building and an additional array on an adjacent building, provide the remainder of the energy to meet a net zero balance. During the summer, the solar array provides hot water to the building and excess heat is sold to the Neighbourhood Energy Utility (NEU) for use in adjacent buildings. In the colder winter months, the Net Zero building derives the balance of its heat energy from the NEU, without which the net zero targets of the building could not be met.
ECONOMY
Although building costs were approximately 16 percent higher than for a conventional multi-unit housing complex, it is estimated that the increased initial costs will be off-set by energy savings over the next 25 years. The development and construction of projects such as the Net Zero building contributes to the evolution of green economy of Vancouver and increases its profile as a North American hub of green building innovation.
“Green” products and technology employed in the development of the New Zero Building include
COMMUNITY
The Net Zero building plays a pivotal role in the SEFC neighbourhood by providing sustainable housing for a rapidly growing demographic of seniors. The project also places great emphasis on education and capacity building among occupants. For example, user manuals educate occupants on more energy efficient and economically smart lifestyles. Also, all occupants are asked to agree to a “living contract” committing them to an energy-efficient lifestyle.
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