Berkeley Lab Demonstrates Use of TLEDs and Automated Shades to Save Electricity

The U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) reports that it was able to use a combination of LED lighting and automated shades, on one floor of a high-rise office building in New York City to reduce lighting energy consumption by almost 80 percent in some areas. Berkeley Lab set up the “living laboratory” at the New York office building so its researchers could test four sets of technologies on one floor of a building that by itself covers 40,000 square feet.

The lab partnered with the Building Energy Exchange (BEEx), an independent nonprofit on the project that intended to demonstrate that even in relatively modern office buildings, installing the latest smart, actively controlled LED lighting and shading can drastically lower energy costs. According to Berkeley Lab scientist Eleanor Lee, who led the project, these results will help accelerate market adoption of emerging energy-saving technologies.

“Context matters when it comes to figuring out where the market barriers are with respect to contractors, facility managers, and office workers – isolated tests in a laboratory environment are often not enough,” she said. “Reducing stakeholders’ uncertainty about performance and occupant response in a real-world setting can be critical to accelerating market adoption.”

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Berkeley Lab and BEEx collaborate a 'living lab'-- thermal imaging of lights and window shades

Berkeley Lab and BEEx collaborate a ‘living lab’– thermal imaging of lights and window shades

The project used thermal imaging to measure surface temperatures near the window and evaluate the occupants’ level of thermal comfort. On the living lab floor, dimmible LEDs with new sensors replaced T5 fluorescent lights. These LED lamps were adjusted during the day to accommodate occupancy and daylight levels within the space.

Automated shades were raised or lowered to open up views to the outside. These shades could be raised allow daylight to come through the windows, or lowered to reduce glare as needed.

Baseline Measurement Taken for One Year Before Upgrade

Before the upgrades were installed, the researchers monitored the energy usage for the floor for one year. The researchers found that compared to the baseline condition, energy use for lighting in the living lab’s 40-foot deep perimeter zone declined 79 percent. Also, the associated peak lighting electric demand declined 74 percent. Much of the savings resulted from the switch from fluorescent lamps to LEDs retrofit lamps (TLEDs). Additional savings came from being able to dim lights across the floor, not just next to the windows.

According to the researchers, the lighting system’s controls enabled more granular fixture-by-fixture monitoring and control, and wireless sensors and communications enabled the zone control to be customized at the work-group level.

Many of the choices related to the control configuration were driven by the desire to keep the interior areas bright and maintain access to outdoor views. Despite the tremendous reduction in energy consumption, people surveyed on the living lab floor were generally content with both the indoor temperatures and the lighting levels.

Although heating and cooling weren’t monitored during the study, researchers estimated that this building-wide retrofit would have delivered total electricity cost savings of about $730,000 a year, assuming an average rate of $0.20 per kilowatt hour.

Along with strong diagnostic and troubleshooting tools, the researchers emphasized the importance of installer and operator training to boost the adoption of the technologies.

BEEx Created Educational Resources about Lighting of Commercial Spaces

BEEx served as local managers for the Living Lab and documented lessons learned during the entire process of technology selection, procurement, and installation. With these lessons, BEEx formed the backbone of multiple educational resources ranging from exhibits to professional training sessions and toolkits. These educational resources target professionals who make decisions about lighting in commercial spaces.

“Using everything we learned on this project, we’ve developed a series of tools that will really help the engaged design professional or building owner make better decisions about lighting system upgrades, and avoid the common pitfalls on the road to a high-performance office space,” said Yetsuh Frank, BEEx managing director of strategy and programs.”

Funding for the study came from the Department of Energy’s Office of Energy Efficiency and Renewable Energy and by the New York State Energy Research and Development Authority.

Berkeley Lab to Continue Work with BEEx and Building Owners

Berkeley Lab plans to continue work with BEEx and building owners to further encourage the adoption of these advanced technologies, and through partnerships with the DOE and manufacturers to develop next-generation products for improved energy efficiency.