Compact building forms and daylighting
Feb 1, 2010 12:00 PM
Up to one third of a typical school's energy use can come from artificial lighting. Although daylighting is an important energy conservation strategy in and of itself, reducing overall energy use significantly requires a combination of strategies. For example, a building's massing and skin can play a vital role.
Compact multi-story buildings have many sustainability benefits: they might limit sprawl, allow for more greenspace to absorb and filter water, provide material and energy savings, and limit heat gain or loss. Such building configurations are not ideal, however, for creating optimal daylighting conditions. Compact buildings are characterized by a smaller surface-to-volume ratio, resulting in increased building depths and greater distance from exterior windows. The challenge of directing daylight from outside into the building grows with multi-story buildings, where interiors are increasingly more difficult to light from the roof.
High windows, light shelves, and reflective surfaces maximize the amount of sidelight entering a building. Potential issues with sidelighting (namely uneven light distribution and glare) can be avoided by introducing light through the roof with roof monitors and skylights with deep, splayed wells. When light can be introduced from above, the depth of the plan is no longer a limitation, but bringing light into the lower floors of multi-story buildings becomes challenging. Light wells and tubular skylights can be efficient in directing daylight into lower floors. Strategically placed and carefully designed courtyards or atria also enable light to enter a compact building. Such spaces also connect the inside occupants to the outdoors and can provide useful shared teaching and collaborative space. Additionally, trees in an exterior courtyard provide shade and protect from glare. Combined with water collection and reuse features, they create a pleasant microclimate in a hot dry climate.
Read the main story, "Light Moves," to learn more.
