Lighting accounts for about a third of electrical energy consumption in commercial buildings. As advanced energy-saving lighting controls still have a minority penetration in the existing building stock, building owners have a major opportunity to reduce energy costs with lighting control. Adoption of advanced lighting controls faces the usual hurdles affecting all energy-efficient lighting, including […]
Last month at LightingControlsAssociation.org, we published an article about how to establish daylight zones in sidelighted (windowed) building spaces. We looked at an industry rule of thumb and then how the latest generation of energy codes and standards address it. In review, when designing an energy-saving daylight harvesting control system, a critical decision is to […]
When designing an energy-saving daylight harvesting control system, a critical decision is to establish lighting control zones, identifying lighting loads to be separately controlled. Before this decision can be made, however, we must first determine the daylight zones. A daylight zone, also called the daylight area (expressed in square feet), is defined by the ASHRAE/IES […]
The Lighting Controls Association is pleased to announce that it has updated EE201: Introduction to Lighting Control, a popular offering in the Association’s Education Express series of online distance education courses about lighting controls. The course, authored by Craig DiLouie, principal of ZING Communications, Inc. and LCA’s Education Director, provides an introduction to daylight harvesting […]
As sunlight scatters through the atmosphere, it turns the entire sky dome into a daylight source. The proper use of daylight coupled with thoughtful electric lighting design and control applications can significantly reduce energy used by lighting. The ALG Online (Advanced Lighting Guidelines) devotes an entire chapter to understanding the impacts of daylight on commercial spaces and effective ways to integrate daylighting strategies into low-energy building designs. Click to learn more.
Because of the strong energy savings potential offered by daylight harvesting, coupled with advancing technology, codes and standards are now beginning to address daylight harvesting—specifically, International Energy Conservation Code (IECC) 2009, ASHRAE/IES 90.1-2010, ASHRAE 189.1 and Title 24-2008.
Lighting Controls Association members will present “Design of Electric Controls for Daylighting,” a three-hour workshop, during the Daylighting Institute at LIGHTFAIR 2011.
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?