Ben Franklin Elementary School


The primary and fundamental goal of the design team was to create synergies among consultants, ensuring that all elements of the building would work together to respond to seasonal changes in weather and occupancy. Implementing the concepts of year-round natural ventilation, daylighting, and eliminating mechanical comfort cooling required close coordination of all disciplines.

Using the concepts of thermal buoyancy and pressure differentials, thermal chimneys create a stack effect in the building, drawing fresh air through low-level perimeter windows and louvers and venting it at high level. Extensive computational analysis was performed to perfect the geometry of openings through each classroom. Whole-building natural-ventilation design techniques, affecting building orientation, windows, shading, construction materials, daylighting, and ventilation openings, were employed to allow for passive cooling throughout the building during occupied seasons. In heating mode, the air passes over fin-tube water heating elements located at the perimeter louvers before it is introduced into the classroom spaces.

Occupancy sensors and automatic dimming controls were installed on light fixtures in all classrooms. Daylighting models of the classrooms, activity areas, library, gym, and commons were analyzed to ensure that the spaces would meet optimal design criteria and achieve a 2% outside illumination baseline. Automatic dimming controls adjust light levels in the classrooms to maximize the energy efficiency benefit of the daylighting. Daylight harvesting is expected to reduce lighting energy usage by 25% in these areas.

Mechanical systems were designed to avoid unnecessary redundancy. Instead of "doubling up" on equipment to ensure complete backups or relying on large safety factors the design team used the ASHRAE design criteria for the heating systems. Each condensing boiler was sized for 60% of the total capacity rather than 100%.