Category: Research

Study Measures Light Exposure and Its Effects on Sleep and Behavior in Nursing Care Center

The Pacific Northwest National Laboratory (PNNL) recently released the results of a U.S. Department of Energy-funded study, Measuring Light Exposure and its Effects on Sleep and Behavior in Care Center Residents.

The Pacific Northwest National Laboratory (PNNL) recently released the results of a U.S. Department of Energy-funded study, Measuring Light Exposure and its Effects on Sleep and Behavior in Care Center Residents. Carried out in collaboration with the Brown University School of Public Health Center for Long-Term Care Quality & Innovation, the American Health Care Association/National Center for Assisted Living, and the Center of Design for an Aging Society, the study builds on a prior PNNL field evaluation of tunable lighting at the ACC Care Center, a 99-bed nursing center in Sacramento, California, with a large population of dementia patients.

LED technology offers the ability to tune spectral content and intensity. It’s proposed that spectrally tunable and output-selectable LED lighting may improve dementia behaviors and sleep issues, which are common among residents of nursing-care centers. Some products propose to mimic the lighting color and intensity variations of daylight over the course of the day, with suggested benefits to circadian rhythm entrainment and health. But to date, most of the research on programmable, tunable LED lighting has had significant methodological limitations, did not use current lighting technology, or did not report enough detail about light and spectral exposure to be comparable to models of circadian health.

To address this, PNNL researchers conducted a study of tunable lighting at the ACC Care Center. The study involved a partnership between experts in lighting design, environmental design, and light measurement; experts in measuring resident behavioral outcomes in nursing centers; and leaders from a nursing center with previously installed programmable, tunable LED lighting. The objective was to test a strategy for measuring and documenting light exposure for typical nursing-center residents, and to evaluate the data in terms of various metrics for human circadian responses over the course of a day.

Three long-term-care corridors featured lighting settings that mimicked the facility’s former fluorescent lighting (static lighting) or that were programmed to change in spectrum and intensity (tuned lighting). The nighttime lighting mode had overhead LED lights delivering 2700K ambient light, dimmed to 21% output. The spectrum was designed to minimize blue-cyan energy—the portion of the visible light spectrum most associated with human circadian melatonin levels and, as such, affects sleep quality and duration.

The daytime setting had 100% output at 6500K, designed to maximize energy emitted in the blue-cyan range. A transition state between the nighttime and daytime settings had 4100K and 100% output.

Corridor at the ACC Care Center showing three of the programmed settings for the tunable LED lighting.

The results show that residents experienced fewer nighttime sleep disturbances when their corridors were assigned to the tuned and dimmed lighting. Other findings center on lessons learned for care-facility operators, lighting designers, technology developers, and standards developers and recommendations for future research.

While the primary focus of this study was to establish feasibility and best-practice protocols for implementing tuned lighting in the nursing-home setting, results suggest that tuned lighting had a positive effect on residents’ sleep. The researchers were able to develop a methodology for collecting light-exposure data and analyzing those data using three different models for circadian health: circadian stimulus, melanopic/photopic ratios of the light received at the eye of the resident, and equivalent melanopic lux. This protocol will inform future studies on programming and evaluating tuned lighting systems in an institutional setting.

Click here to get the full report.

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LRC Evaluates Hybrid UV Lighting System to Reduce Healthcare-Associated Infections

The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute is investigating light-based disinfection using short-wavelength light, ranging from ultraviolet (UV) to blue light (200 nm to 410 nm).

The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute is investigating light-based disinfection using short-wavelength light, ranging from ultraviolet (UV) to blue light (200 nm to 410 nm). Short wavelengths can kill pathogens through a variety of pathways, depending upon the wavelength, the duration, and the amount. The expectation is that decontamination of room surfaces will improve over manual cleaning methods.

LRC researchers tested a new hybrid lighting system, developed by GE Current, a Daintree company, which was designed to provide both visible white light and disinfecting UV-A. The system was retrofitted into a modern hospital newborn intensive care unit (NICU) at the Memorial Beacon Children’s Hospital in South Bend, IN. The UV-A dosing was set to levels calculated to be safe for human occupation.

Eight-hour exposures on counter surfaces were effective for suppressing pathogens identified by the CDC as highly problematic for healthcare facilities. LRC researchers also conducted a survey aimed at assessing the opinions of professional staff working in the NICU about the hybrid lighting system. Staff members accepted the hybrid lighting system, and the comments about the system were generally positive. An analysis of photodegrading effects suggested that UV-A resistant equipment and furnishing may need to be installed with this technology.

The findings were recently published in Lighting Research & Technology.

“Reducing healthcare-associated infections is critically important,” said LRC professor Dr. Mark Rea. “Unfortunately, the prevalence of these infections is only expected to rise. The present findings should form the foundation for the next generation of this technology.”

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Lighting Research Center Partners With Eaton on 3D Printed LED Luminaires

Rensselaer’s Lighting Research Center has partnered with Eaton Corporation on a project to develop a complete additively manufactured, LED-integrated luminaire. Under funding from the United States Department of Energy, the project will address the main barriers to widespread adoption of additive manufacturing technology (also known as 3D printing) as applied to solid-state lighting.

Rensselaer’s Lighting Research Center has partnered with Eaton Corporation on a project to develop a complete additively manufactured, LED-integrated luminaire. Under funding from the United States Department of Energy, the project will address the main barriers to widespread adoption of additive manufacturing technology (also known as 3D printing) as applied to solid-state lighting.

Over the next two years, the project partners will conduct material science, electronics, optics, and advanced manufacturing research to investigate the transformational potential of a fully additively manufactured, LED integrated luminaire, with a focus on reducing the cost of the luminaire’s dominant subsystems. Components of a solid-state luminaire will be fabricated using additive manufacturing methods, including mechanical and thermal management structures, electrical and electronic structures (on three-dimensional representative substrates), and optical and light reflector structures.

The project, led by Eaton, was competitively selected through the DOE’s SSL R&D Funding Opportunity program, and draws upon the Lighting Research Center’s growing expertise in 3D printed lighting research.

Click here to learn more about the LRC’s 3D printing research.

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Light Observations Suggest Universe May Not Be Flat But A Sphere

Observation data produced by the Planck Satellite Mission suggests the universe may not be flat, as popularly believed by scientists, but a sphere.

Observation data produced by the Planck Spacecraft Mission suggests the universe may not be flat, as popularly believed by scientists, but a sphere.

In an article published by VICE:

Most observational evidence favors a model of a flat universe, in which light travels across the cosmos in a straight line. But a team led by Eleonora Di Valentino, a cosmologist at the University of Manchester, identified a key piece of data that suggests space may be curved into a closed cosmic sphere, meaning that a beam of light would eventually loop around the entire cosmos to return to its point of origin. The team’s results are based on new data released from the Planck mission, a European Space Agency (ESA) satellite that operated from 2009 to 2013.

The Planck spacecraft was designed to map cosmic microwave background (CMB) radiation, the afterglow of the Big Bang believed to be the origin of the universe. At 13 billion years old, it’s the oldest light in the universe.

According to Planck’s measurements, the CMB is being gravitationally lensed much more than expected. One possible explanation to account for this observation is that there is a curvature woven into the fabric of spacetime.

A flat universe remains the accepted cosmological model, but the Planck Mission findings invite fresh investigation that may challenge the popular theory.

Click here to check out this article.

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DOE Study Validates TM-30 Color Preference Specification

The Pacific Northwest National Laboratory (PNNL) recently released the results of a U.S. Department of Energy-funded study, published in Lighting Research & Technology, that validates color preference specification criteria based on American National Standard Institute and Illuminating Engineering Society TM-30-18. The results support TM-30 Annex E recommendations that allow lighting professionals to communicate different color rendition goals (preference, vividness, and fidelity) with far greater precision than prior methods.

The Pacific Northwest National Laboratory (PNNL) recently released the results of a U.S. Department of Energy-funded study, published in Lighting Research & Technology, that validates color preference specification criteria based on American National Standard Institute and Illuminating Engineering Society TM-30-18. The results support TM-30 Annex E recommendations that allow lighting professionals to communicate different color rendition goals (preference, vividness, and fidelity) with far greater precision than prior methods.

In the new study – the third in a PNNL series – 90 lighting conditions with systematically varied color rendition and chromaticity were evaluated by 25 participants who provided ratings for normalness, saturation, preference, and acceptability. The lighting conditions were designed to test the bounds of previously proposed color preference criteria, while also verifying their applicability across different correlated color temperature and Duv values. In keeping with the preceding work, there were substantial differences in ratings based on color rendition, but minimal differences based on chromaticity. This supports the use of color rendition specification criteria that are independent of chromaticity (within the range of nominally white light).

While considerable effort has been made to understand correlations between subjective evaluations of color quality (i.e., color preference, color naturalness, color vividness, color acceptability) and the metrics used to characterize light sources, little attention has been given to establishing new color rendition specification criteria, which are the primary way color quality is addressed in practical applications.

The new TM-30 Annex E criteria may be a valuable tool for improving lighting quality and balancing the tradeoff between color rendition and energy efficiency.

Check out the study and its results here.

Mean preference rating for 90 scenes grouped by color rendition condition. Conditions 3-7 and 10 have roughly equal color fidelity but were not equally preferred, demonstrating the value of using 3 metrics rather than just color fidelity.

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DOE Announces RFI on Lighting Research and Development Opportunities

The U.S. Department of Energy’s (DOE’s) Building Technologies Office (BTO) has issued a Request for Information (RFI) (DE-FOA-0002160) to seek broad stakeholder input to inform the strategic direction of the DOE lighting research and development (R&D) portfolio. The purpose of the RFI is to better understand how lighting research goals can be refined to reflect evolving technology needs and inform related R&D activities.

The U.S. Department of Energy’s (DOE’s) Building Technologies Office (BTO) has issued a Request for Information (RFI) (DE-FOA-0002160) to seek broad stakeholder input to inform the strategic direction of the DOE lighting research and development (R&D) portfolio. The purpose of the RFI is to better understand how lighting research goals can be refined to reflect evolving technology needs and inform related R&D activities.

BTO’s Lighting R&D Program aims to drive the development of advanced lighting solutions through innovative, early-stage R&D. This research supports BTO’s overall goal to improve the energy productivity of buildings without sacrificing occupant comfort or product performance. The program is guided by the Lighting R&D Opportunities (RDO) report, which is updated annually with input gathered from the U.S. lighting science R&D community, the annual DOE Lighting R&D Workshop, and ongoing engagement with lighting researchers.

The Lighting RFI is requesting stakeholders to:

  • Provide critical input on current Lighting R&D Program direction, activities, and opportunities.
  • Identify impactful lighting R&D opportunities within general illumination that are absent (or underrepresented) in the 2018 DOE Solid-State Lighting RDO document.
  • Identify impactful lighting R&D opportunities where immediate applications are beyond general illumination but have potential to help save energy in the built environment.

Stakeholder responses to the RFI will inform updates to future editions of the RDO, and ultimately, the strategic direction of the lighting portfolio moving forward.

How to respond to this RFI:

(This RFI is not a Funding Opportunity Announcement; therefore, EERE is not accepting applications at this time.)

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Scientists Discover New Property of Light

Researchers in the U.S. and Spain recently announced they have discovered a new property of light, called self-torque. They found that light can be twisted.

Researchers in the U.S. and Spain recently announced they have discovered a new property of light, called self-torque. They found that light can be twisted.

Phys.org reports:

Scientists have long known about such properties of light as wavelength. More recently, researchers have found that light can also be twisted, a property called angular momentum. Beams with highly structured angular momentum are said to have orbital angular momentum (OAM), and are called vortex beams. They appear as a helix surrounding a common center, and when they strike a flat surface, they appear as doughnut-shaped. In this new effort, the researchers were working with OAM beams when they found the light behaving in a way that had never been seen before.

Phys.org added:

The researchers suggest that it should be possible to use their technique to modulate the orbital angular momentum of light in ways very similar to modulating frequencies in communications equipment. This could lead to the development of novel devices that make use of manipulating extremely tiny materials.

Get the story here.

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ELECTRICAL CONTRACTOR Publishes Lighting Survey Results

Electrical contractors consider themselves highly influential in lighting-equipment selection for both new construction and retrofit projects. That’s one key finding from the 2019 CII Lighting Trends Survey, which ELECTRICAL CONTRACTOR conducted using the 1,000 members on its Subscriber Research Panel.

One of my contributions to the April 2019 issue of ELECTRICAL CONTRACTOR is the results of a survey about contractor attitudes in the lighting market.

Key findings:

  • A majority of respondents said their 2018 lighting revenues from CII new construction/major renovation projects (51 percent) and retrofit projects (54 percent) increased in 2018.
  • A majority of respondents reported they expect their lighting revenues from CII new construction/major renovation projects (60 percent) and retrofit projects (65 percent) to increase in 2019.
  • The average respondent is fairly familiar with major lighting trends. The greatest familiarity is with networked lighting controls and wireless lighting controls. Respondents are least familiar with the IoT, which is not surprising as it is new and evolving.
  • A majority of respondents discussed lighting quality (88 percent), color-tunable LED lighting (58 percent), and energy information (51 percent) as lighting product features with customers in 2018. Customers were most interested in lighting quality, followed by energy information and automatic maintenance alerts.
  • Seventy-nine percent of the lighting installed by the average respondent in CII new construction/major renovation projects in 2018 was LED-based.
  • The average respondent was called back to the job site to address operating issues in 19–22 percent of their 2018 projects involving lamps, light fixtures, lighting controls and networked controls.
  • The average respondent has a significant comfort level with novel technologies such as networked lighting controls (51 percent being “very comfortable”) and wireless controls (53 percent). They are least comfortable with the IoT (33 percent).

Click here to read it.

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DOE Releases Study on Handheld Flicker Meters

The U.S. Department of Energy (DOE) recently released findings of a new study on handheld flicker meters. The study found that handheld flicker meters today are capable of providing performance nearing that of a benchtop meter in a controlled environment.

The U.S. Department of Energy (DOE) recently released findings of a new study on handheld flicker meters. The study found that handheld flicker meters today are capable of providing performance nearing that of a benchtop meter in a controlled environment.

Click here to check it out.

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PNNL Seeks Used LED Street or Area Luminaires for Study on Optical Changes and Dirt Accumulation

On behalf of DOE’s SSL Program, the Pacific Northwest National Laboratory (PNNL) is planning to conduct a study examining dirt depreciation and other optical changes occurring in LED street or area lights over long-term periods of performance, potentially approaching their full life cycles. For the study, PNNL seeks LED street or area lights that, ideally, are nearing the end of their anticipated life; however, any luminaire with more than 10,000 cumulative hours of operation will be considered.

On behalf of the U.S. Department of Energy Solid-State Lighting (SSL) Program, Pacific Northwest National Laboratory (PNNL) is planning to conduct a study examining dirt depreciation and other optical changes occurring in LED street or area lights over long-term periods of performance, potentially approaching their full life cycles.

Stable long-term performance is a key selling point for LED luminaires, and for streetlights in particular. However, documented field experiences over a full life cycle are scant, because even the first generation of installed units are just now approaching their initially projected end of life (at 4,100 hours of annual operation, a 50,000-hour expected lifetime extends just over 12 years).

For the study, PNNL seeks LED street or area lights that, ideally, are nearing the end of their anticipated life; however, any luminaire with more than 10,000 cumulative hours of operation will be considered. There is no restriction on the type of luminaire, although a key requirement is the availability of a performance baseline. This can be through a pre-installation photometric test or via an equivalent unused luminaire (“shelf stock”) that can be submitted for comparison purposes. Compensation for submitted luminaires is available through replacement with similar make and model luminaires.

The following must be known about the luminaires submitted: total hours of use (within ±500 hours), installation location, and number of cleanings (if any) the luminaire has had. It is preferred, although not required, that the used luminaire still be functional. Only one used and one unused luminaire are needed, although multiple used and unused luminaires may be submitted.

Click here to learn more.

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