WattStopper has launched an electric lighting control technology for daylight harvesting that it says produces better control of electric lighting as well as improved energy and cost savings.
According to the company, the LMLS-600 dual-loop photosensor control is the first device on the market to combine open-loop and closed-loop photo sensing strategies, which improves the accuracy and reliability of daylight sensing in spaces with skylights.
The device is the result of research and development conducted in the labs of the California Lighting Technology Center (CLTC), part of the University of California, Davis.
CLTC monitored a demonstration of the dual-loop control system at Walmart’s 24-hour West Sacramento store for a full year. Energy savings measured 36 percent, on average, compared to 24 percent from an open-loop control system. This 50 percent improvement in efficiency reduced annual lighting energy use by 113.5 MWh and saved $14,500 in electricity costs.
CLTC co-director Dr. Konstantinos Papamichael says the product combines advantages of closed-loop and open-loop strategies while eliminating the disadvantages of each.
Closed-loop photo sensors do not always respond well when there are changes within a space. Such changes can occur, for example, when a retail store updates its displays, placing items of different colors, shapes and reflective finishes underneath skylights and sensors.
Open-loop photosensors resolve this issue, but they do not always correspond with ambient light levels in the space, especially at the beginning and end of the day, and during partly cloudy conditions. This can result in distracting light-level changes.
The LMLS-600 also features two highly accurate silicon photodiodes that mimic the human eye’s photopic response.
The dual-loop photosensor is the newest component in WattStopper’s Digital Lighting Management (DLM) system. Following an automatic setup process, it works with DLM room controllers to deliver atomatic on/off switching, step dimming or continuous dimming. The LMLS-600 also recalibrates itself automatically, so it constantly adapts to interior space changes, as well as lamp lumen depreciation and changes in daylight contribution, without the expense of manual maintenance.
The company expects the dual-loop control technology to achieve wide consumer acceptance and yield high-energy savings, especially in California, where building energy codes will soon require electric lighting controls in the majority of commercial spaces with skylights.
Earlier this month, WattStopper announced that its Niagara AX driver module streamlines integration when WattStopper Digital Lighting Management (DLM) controls are combined with Niagara controllers in high-performance buildings.