Natural ventilation goals, lab airflow requirements
Optimizing energy performance while maintaining occupant safety
at the University of Washington.
A 2009 Carnegie-Mellon study found that fifty percent of the earth’s surface presents local climates capable of conditioning building spaces for four to six months of the year. With fully 97% of annual operating hours falling within the adaptive comfort range, Seattle presents ideal circumstances for reducing building energy use with natural ventilation.
The interdisciplinary program for the University of Washington’s new 90,000 sf Molecular Engineering building, however, calls for the immediate adjacency of labs with safety ventilation requirements and the offices that will be conditioned with natural ventilation. With cross ventilation not possible, a stack configuration will provide airflow. Spatial organization, sizing, and window intake strategies were informed by CFD studies by AEI of typical and worst-case conditions.
Site and phasing requirements necessitate north-south orientation; labs are west-facing due to street traffic noise and pollution on that side precluding operable windows. East-facing solar gain is reduced by 80 percent through shading and high performance glazing. Daylight is predicted to reduce electric lighting load by over 30 percent annually. With east-facing offices unable to benefit from prevailing winds to drive ventilation, the stack height and size were increased and outlets configured to maximize draw. Fan assists will compensate, as required, for limitations to stack sizes.
