Each entrant or team will produce a building design for an approximately 150 unit/up to 14 stories affordable, residential apartment building with a ground floor grocery store that is as close to zero net energy as possible. The competition jury will review each entry for documentation of energy performance as well as the architectural integrity of the design.
Designing to Zero Net Energy
Although there are several ways to interpret zero net energy, this competition will be using the zero net site energy definition. A zero net site energy building project produces at least as much energy as it uses over a year when accounted for at the site level (as defined by the boundaries of the project, whether one or multiple buildings). This definition does not include the embodied energy in building materials or account for transportation of materials and people to and from the site. This definition does include all forms of energy used on the site (most commonly electricity and natural gas).
Since zero net energy is a performance-based metric measured over time, entrants will need to demonstrate that their submitted design solutions have a reasonable expectation of approaching a zero net energy goal. At its most fundamental level, designing a zero net site energy district or building is a balancing act of reducing building loads and increasing efficiency enough to be able to produce sufficient on-site renewable energy to completely off-set the remaining projected energy use over the course of a year.
Zero net energy is easiest to achieve for smaller buildings and buildings with less energy-intense uses. As a rule of thumb, zero net energy becomes harder to achieve in buildings over a few stories tall. This is because the increased level of occupancy/energy demand is not typically balanced by an increased ability to generate energy onsite. It may be supposed that a tall, thin high-rise building will not have enough roof space to accommodate all of the solar that it would need to off-set its energy demand. Similarly, certain energy intense uses- for example, hospitals or technology centers- would also pose a special challenge for becoming zero net energy sites. Since the Architecture at Zero 2013 competition site design is for a large, mixed-use, multi-storied apartment complex, part of the challenge for competition entrants will be to propose creative solutions for integrating renewables on-site as well as maximally leveraging efficiency. The goal is to get as close to zero net energy as possible, bearing in mind that designs may not get all of the way there.
All buildings and building district plans designed as part of the competition must be grid-tied. “Grid-tied” buildings maintain a connection to the electrical grid. Maintaining connection to the grid allows for the natural fluctuations of renewable energy sources without the need for on-site energy storage. When insufficient energy is generated by on-site renewables to meet the demand from building loads, electricity is drawn from the grid; when on-site renewables generate a surplus of electricity, the surplus electricity is exported to the grid.
Integration of Renewable Energy Sources
Each building design and each district energy plan will need to include at least one renewable energy source. For this competition, “renewables” will be defined as solar power, wind power, microhydro, geothermal, and biomass/biofuel. Renewable generation is distinct from load reduction, and both are components of a successful zero net energy design.
Waste Heat Recovery
To increase the chances that designs will approach zero net energy, designs will be required to draw upon waste heat from the mechanical systems in the ground floor grocery store to serve a portion of the water or space heating load requirements for the housing units.