Daylight harvesting’s value proposition is fairly simple: As daylight levels increase in a space, electric light levels can be automatically reduced to maintain a target task light level and save energy. All automatic daylight harvesting control systems need a device that can measure light levels and signal a controller to dim or switch the lights in response to daylight contribution. This device is called a photosensor. The photosensor is a small device that can include a light-sensitive photocell, input optics and an electronic circuit used to convert the photocell signal into an output control signal, all within a housing and with mounting hardware.
What are the benefits of combining advanced lighting control strategies in the same space? Are the energy-saving benefits of lighting controls persistent over time? Can advanced lighting controls be successfully applied to open offices given concerns about jurisdiction conflicts, lighting uniformity, etc.? Can they enhance worker satisfaction? A new office lighting field study addresses these questions. Involving about 90 workers in a real-world open-office environment, the one-year study determined that occupancy sensing, daylight harvesting and individual occupant dimming control worked together in the building to produce average energy savings of 47% while correlating with higher occupant environmental and job satisfaction. The study demonstrates that sophisticated lighting control strategies can be combined successfully to generate persistent, large energy savings in open-plan offices while improving occupant satisfaction with their jobs and workspace.
The study revealed that only 25 percent of the sidelighting photocontrol systems in the studied buildings were functioning well, whereas almost 100 percent of the toplighting photocontrol systems were found to be functioning well in the previous study. What went wrong?
The Lighting Controls Association (LCA) has announced the availability of EE201: Daylight Harvesting Control, a new course added to its popular Education Express program. Residing at the Association’s website www.aboutlightingcontrols.org, Education Express provides in-depth education about lighting controls and controllable ballast technology, application, system design and commissioning.
The Weidt Group conducted a study of daylight harvesting projects to find out if daylight harvesting projects are living up to their expectations. The team—consisting of Eijadi, Prasad Vaidya, Tom McDougall, Jason Steinbock and Jim Douglas—reviewed dozens of completed projects, most of which were sidelit using windows, and separated the success stories—some of them operating for 25 years—from projects they considered to be failures.
Pier 69 on Seattle’s historic waterfront was built in 1931 to warehouse rolls of metal for the production of canned salmon containers. The only concrete pier on the waterfront, Pier 69 stretches over 750 feet long and 135 feet wide. Hewitt Isley tackled this stolid building to create a new home for the Port of Seattle’s administrative headquarters. Their dynamic reno-vation created what the Seattle Weekly named “one of the grandest indoor spaces in the Northwest.”