BAR Architects and Integral Group’s submission of a net zero student housing community garnered the Special Recognition Award at the 2015 Architecture at Zero design competition, presented by Pacific Gas and Electric Company (PG&E) and the American Institute of Architects, California Council (AIACC).
Siting the buildings with a north-south orientation was deliberate, albeit unconventional. To achieve net zero performance, consideration of building orientation is important, but must be balanced with daylight access and solar control. For residential uses, an east-west orientation would limit direct access to daylight for nearly half of the occupants.
The ØeMission Bay design response lifts the massing, leveraging opportunities to link major green spaces to the north and south, and encourages street level pedestrian flow. Air currents across the site are directed up into the courts and light wells. The facade shading strategy is born of solar insolation analysis. Northwest and southwest facade scrims are shaped by the intensity of the annual solar radiation striking the facade. The opacity of the translucent scrim, directly proportional to the insolation intensity, allows for maximum window to wall ratios while minimizing solar gain. Smaller openings on the eastern facades are designed to reduce thermal loads. In addition, hybrid PV/solar thermal array further shades the facades and light wells.
All living units allow natural ventilation by cracking open the traditional double loaded corridor plan and introducing semi-enclosed light wells. Operable windows on opposing sides of the unit allow free cross flow of air. Light wells act as thermal chimneys, inducing convection currents upward, "pulling" air through the units. Heating is provided through high efficiency air-source heat pumps interconnected with the solar thermal panels on the roof, all of which combine to provide a very low energy solution. The podium is heated and cooled via in-slab radiant conditioning supplied by heat pumps for increased occupant comfort.