Natural ventilation keeps students comfortable in K-12 school
Lynnwood Highschool is an award-winning high school serving grades 9-12 located in Washington just north of Seattle, designed around principles of sustainability and enhancing student learning and community. Among other energy saving strategies, the building features a modern, high-efficiency, fully-automated natural ventilation system in classrooms and science labs. RWDI contributed to the design of this system by providing screening and detailed engineering of that system.
The 220,000 square foot facility was redesigned in 2006 in order to update the existing building. The school was designed around the principle of an Agora – Greek for ‘marketplace’ – that features a central, open community space with four wings radiating from that center. The early concepts for this high school included chimneys driven by internal heat gains as extraction points. However, the building aerodynamics were not ideal due to the physical constraints on the roof. Identifying and implementing sustainable design solutions were also a significant priority for the design team.
Just like our lungs, building ventilation systems are designed to provide us with fresh, healthy air. We wanted to take that approach when designing the ventilation system for a school community.
We began by conducting hand calculations, moved to screening energy modeling and ended up conducting detailed CFD modeling, as well as wind tunnel testing to verify the new design. We proposed a modified use for the chimneys so that they capitalized on the North-South nature of the wind at the site to augment the overall pull of the extracts. Wind tunnel testing was performed to determine the pressures at the extracts, which was leveraged to feed the natural ventilation design.
The advantage of capitalizing on the North-South nature of the wind at the site to augment the overall pull meant that the wind tower/chimney had increased flow capacity and could also serve as a daylighting shaft. The classrooms were constructed without fans and naturally ventilate in summer and winter. The natural ventilation design allows for a continuous flow of outside air, above those recommended for high schools, which permits maximize occupancy in shared areas like classrooms and labs. Lynnwood Highschool received an Energy Star design certification.
The redesigned building also received several design awards including the Council of Educational Facilities Planners International award in 2010, and the James D. MacConnell Award for outstanding new educational facilities. In 2011 the school was recognized as one of ten "Schools of the 21st Century – The Latest Thinking and Best Ideas on the Planning and Design of K-12 School Buildings," by Architectural Record magazine.