The suntubes were very effective in bringing highbay light into a space without using any electricity.
One complication for this project was when we began designing the roof top solar arrays. CalFire requires a 4-foot clearance around all openings, including suntubes, and at the eaves. In our effort to properly daylight the spaces that could not be effectively reached using side lighting, we were also carving out roof top area that would be unavailable for solar modules.
A solution that emerged was moving some of the planned solar PV panels to the canopy over an adjacent work area. This allowed some of the electricity generation to be assumed by a concentrated installation, while freeing up space on the main building for daylighting mixed with a smaller PV footprint.
This project comprised a three-story multi-use building with significant glazing on all orientations, using a spandrel glazing system. We assisted the design team in improving the building’s daylight by making suggestions such as glazing performance specifications, altering the footprint shape and rearranging interior spaces to increase the depth of daylighting.
Through modeling, we demonstrated that a thinner footprint provided greater opportunity for daylight and had improved energy performance. The architects - Arris Studio Architects - were then able to create a building with great perimeter daylighting. We then focused on improving interior spaces such as common work areas of the third floor. We recommended a “shared light” strategy where suntubes were placed throughout the corridor, and the interior office doors were changed from solid to glazed, creating more consistent light levels on the top floor from the perimeter to the core.
Initially the owner group also wanted a large skylight in the lobby area but after modeling different scenarios, we suggested multiple suntubes that would still provide ample daylight but reduce glare, prevent UV-light from fading the furniture, and reduce heat gain that would have occurred with a single large skylight. You can see in the image below that four suntubes were located in the interior rectangular space directly in front of double doors to bring in light for occupants deep in the space, while single suntubes provide daylight to both the corridor and the adjacent interior spaces (through glazed doors).