DOE again reports slow improvement in LED downlights, adds R&D grants

The US Department of Energy issued a Caliper Snapshot report on LED downlights that confirms a trend foreshadowed last year, indicating that efficacy improvements have stalled in the category, and the agency also announced some new grants for R&D.

The US Department of Energy (DOE) has issued a new Caliper Snapshot on LED downlights that documents mean efficacy improvement of only 1 lm/W in the past 15 months, although manufacturers have been improving light quality with a rise in the typical CRI of such products. In funding news, the DOE announced eleven new research and development (R&D) grants — ten in the Small Business Innovation Research (SBIR) program and one in the Small Business Technology Transfer (STTR) program that both target critical advances in solid-state lighting (SSL).

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Downlight performance

The DOE issued a Snapshot reports on LED downlights just over a year ago. And we would not have expected another such report so soon. But clearly the agency is concerned that energy efficiency gains have stalled out in the downlight sector. The 1-lm/W gain over 15 months compares to a 7-lm/W gain for troffers, a 13-lm/W gain for industrial luminaires, a 10-lm/W gain for linear luminaires, a 10-lm/W gain for wallwashers, and a 5-lm/W gain for decorative lighting over the same period. Moreover, mean downlight efficacy is 69 lm/W whereas many of the other products mentioned are near or over 100 lm/W in mean efficacy. The DOE mines such data for Snapshot reports from the specifications entered for luminaires in the Lighting Facts database.

DOE Caliper Snapshot results on the current efficacy of LED downlights versus other luminaire types.

There is no apparent sure reason why SSL manufacturers aren’t delivering commensurate efficacy gains relative to the broad LED lighting sector. The DOE has suggested that downlights were the first indoor sector in which LED sources were quick to surpass legacy sources in light output and quality based on the directional nature of the sources and the application. And manufacturers have likely focused more on cost reduction than on pushing efficacy.

But the DOE did voice concerns that go beyond a missed opportunity to conserve energy. The report pointed out that improved efficacy in LED sources can simplify thermal management, which in turns enables more flexibility in design and form factor. Those factors can potentially result in cost reduction as well.

The good news in the downlight sector is that the DOE says there are designs for most every whim of a lighting designer/specifier in terms of size, look, and style. There are 4633 LED downlights in the Lighting Facts database. The DOE report states that there are a higher percentage of products with a CRI over 90 in the downlight sector than any other sector covered by Lighting Facts. And 96% of the products have a CRI over 80.

The DOE has issued a number of such Snapshot reports in recent years, including a report on troffers early this year. And there was a Snapshot report focused on outdoor area lighting last fall. You can view the complete report on the DOE SSL website.

New SBIR and STTR grants

On to R&D funding, the recent DOE awards are intended to help the industry advance in sync with the DOE’s SSL R&D Plan. The awards again cover both OLED and LED technology. As we covered in a prior article, the DOE continues to believe OLED sources will fill important niches, although the lighting industry seems increasingly skeptical on that possibility.

The eleven fiscal year 2017 (FY17) grants include:

• An SBIR Phase I award to Luminit for using surface patterning to improve OLED light extraction.
• An SBIR Phase I award to OLEDWorks for the development of an ultrathin, curved, high-efficiency OLED light engine.
• An SBIR Phase I award to Pixelligent Technologies for using a 3-D gradient index layer to increase light-extraction efficiency in OLEDs.
• An SBIR Phase I award to Lumisyn for development of nanocrystal-based silicone films that will increase the efficacy of warm-white LEDs.
• An SBIR Phase I award to OLEDWorks for work on a new substrate and encapsulation process that can reduce the cost of OLEDs.
• An SBIR Phase I award to SC Solutions for manufacturing-control technology that can reduce the need to bin LEDs through wafer temperature uniformity.
• An STTR Phase I award to MicroLink Devices for development of alternative semiconductor materials that can overcome loss mechanisms that limit LED performance.
• An SBIR Phase II award to Lumisyn for development of high-efficiency nanocrystals for use in tunable warm-white LEDs.
• An SBIR Phase II award to PhosphorTech for development of hybrid inorganic down-converting systems for LEDs.
• An SBIR Phase II award to Lucent Optics for a wide-area luminaire technology that combines LEDs and flexible light-guiding films.
• An SBIR Phase II award to Pixelligent Technologies for development of cost-effective light-extraction material for OLEDs.

The DOE continues to invest in the SSL sector including other FY17 grants announced back in January. As a recent National Academy of Sciences report pointed out, the DOE SSL program has been instrumental in the lighting sector moving to LED sources more quickly than most experts expected.