DOE updates LED dimming report with Burden Museum lighting details
Gateway reports issued by the DOE illustrate that design/specification teams on long projects need to ensure dimming compatibility late in projects and a hotel project revealed the viability of LED downlights and controls.
The US Department of energy (DOE) has updated a Gateway report initially issued last year with details about the installation of phase-controlled dimming products and LED lighting at the Burden Museum in Troy, NY. Earlier in the summer, the agency also issued a report on the installation of LED downlights along with dimmers in a Columbus, OH Hilton hotel.
The addition to the "Dimming LEDs with Phase-cut dimmers: The specifier's process for maximizing success" Gateway report is a story of how things change with LED-based products during lengthy lighting projects. Moreover, it describes how the team working on the museum avoided problems by adapting late in the game. Jim Brodrick, lighting program manager at the DOE, highlighted the report addition in a recent Postings email, recurring emails that the DOE distributes to anyone interested in the solid-state lighting (SSL) sector.
Phase-cut dimming is a blessing and a curse for designers/specifiers. The controls are low cost and legacy halogen and incandescent lamps work perfectly with any phase-controlled dimmer. LED-based products, however, must include a driver that's capable of interpreting the input from the dimmer and acting on that input in driving the LEDs. We've had numerous features that have discussed the issue including an article written by dimmer-specialist Leviton.
The original Gateway report on dimmers made a number of recommendations for specifiers such as using three-wire circuits when possible and testing controls and lamps/luminaires together in advance. But as Brodrick points out, 18 months elapsed between the specification of the Burden project and the installation -- and such lengthy delays are commonplace in architectural specification projects.
Indeed, with LED technology evolving, there is a likely chance that products will change in such a period. As the installation time drew near, the project team found that some replacement products required higher power on dimmer circuits or that some products worked better with a forward-phase dimmer than with the specified reverse-phase dimmer.
The key point is that the team took the time to discover how changes impacted the plan before installing the products. That step allowed for changes in the plan ranging from dimmer selection to installation of power module interfaces between some dimmers, and lighting zones to handle increased load requirements.
The result of the project is a happy museum staff that now has an energy-efficient lighting system and the ability to set lighting to prescribed levels. None of the installed products have performed erratically and the staff reports that they get accurate low-light settings. The extra steps for the project drove cost up moderately, but the results justify the expense. You can read the full report at the DOE SSL website.
The DOE also issued another Gateway report earlier in the summer that focused on LED downlight products and controls installed in rooms at a Hilton Hotel. The Cooper Lighting Portfolio LED downlight used had won recognition in the 2010 DOE Next Generation Luminaires (NGL) program. Alternatively, the project team noted that the Philips Lighting Lightolier Calculite product could also be used.
The guest-room-focused report involved seven or more 15W downlights in each of 484 guest rooms. Moreover, the team installed wall-switch phase-controlled dimmers for many of the lights. The project was installed in 2012, but subsequently the DOE visited in 2014 for a post-occupancy assessment.
The LED downlights deliver 50% baseline energy savings relative to the compact fluorescent lamps (CFLs) that would have been the natural alternative. The team found that the project delivered 20% lower energy usage than prescribed by code. Furthermore, the project designer believes the LED lights provide better beam distribution and superior color rendering to the CFL alternatives.
The guest-room retrofit was part of a larger lighting makeover at the hotel. The larger project won recognition in the 2013 Cooper Source Awards program, as we covered in a feature article on the program.