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Good Day Sunshine
Complex daylighting analysis proves the power of trees.
Courtesy SOM

Swiss healthcare giant Hoffmann-La Roche hired Skidmore, Owings and Merrill to design its Indianapolis lab facility, and ordered the firm to uphold Swiss standards for energy efficiency.

The two-story Roche Diagnostics Training Center is designed around a central daylit atrium that collects sunlight through a series of light monitors poking out of the penthouse level. Automatic blinds block low-angle and direct solar penetration to keep glare in check, and the overall form is optimized to let in light.

It is a notion SOM took to an extreme, mounting a computational probability study that aimed to reduce energy use by letting in enough sunlight to illuminate the two-story workspace without overwhelming it with glare.

Placing shade trees in key areas is a common way to avoid overloading a glassy building with sunlight. SOM’s process with Roche explored that strategy to a new level of detail. The firm built a model of a thorn-less honey locust tree in Revit and Rhino and placed a row of this digital vegetation around the building model. The software simulated the seasonal change in leaves on the trees from May through October. “We know it helps and here is how we can prove it,” said SOM Engineer Sergio Sádaba. “Trees and daylighting can be mutually beneficial.”


The difference that the trees have on the building’s energy consumption is visible in a projection of 24 months of energy bills. The latest ASHRAE standards—the industry association for HVAC professionals—put a new baseline building somewhere between a high school and an office in terms of energy use per square foot. SOM’s design for Roche proposed a 68 percent reduction in energy use, putting the high-tech lab facility’s consumption below ASHRAE standards for a high school.

All of the building’s interior occupied spaces are lit entirely with LEDs that augment the daylighting scheme. The team also used RadTherm, a program typically used by automakers, to compute comfort and heat throughout the space. Radiant panels provide heating and cooling, while ventilation ductwork beneath the floors helps stratify interior air quality. The building exhales ventilation exhaust at a high rate through a perforated monitor.

SOM’s study showed the value of trees in curbing energy usage, as well as controlling glare. Engineer Sergio Sádaba said comfort was also a key goal. “To achieve a well-lit building doesn’t mean you need to have glare,” he said. “We wanted to be sure we had enough daylight but that we didn’t have a problem with it.”

Chris Bentley