Category: Research

US EIA Releases 2020 RECS Housing Characteristics With Some Lighting Use Data

The US EIA that releases the data is part of the US DOE. The 2020 Residential Energy Consumption Survey (RECS) provides household characteristics and energy usage indicators for the estimated 123.5 million homes in the United States in 2020.

The US EIA that releases the data is part of the US DOE. The 2020 Residential Energy Consumption Survey (RECS) provides household characteristics and energy usage indicators for the estimated 123.5 million homes in the United States in 2020. The first release of 2020 RECS data includes preliminary estimates on the structural and geographic characteristics of homes, types of electronics and appliances used within them, lighting characteristics, demographic characteristics, and household energy insecurity.

Between 2015 and 2020, homes with most or all indoor LED lighting increased from 4% up to 47%. Over the same time period, homes using mostly or all incandescent or halogen dropped from 32% down to 15%. In 2020, 82% of homes used at least one LED indoor bulb, while 61% of homes used at least one incandescent or halogen bulb indoors.

Find the 2020 RECS Survey Data here.

 

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Light-Operated Computer Chip Implements All 5 Basic Logic Operations Without Electricity

The demand for next-generation computers that can quickly calculate and process a lot of information is rapidly increasing. A logic device is a circuit that obtains an output value by applying one or more logic inputs to certain logic operation (AND, OR, etc.). A logic circuit can be made by combining a plurality of electronic transistors.

The demand for next-generation computers that can quickly calculate and process a lot of information is rapidly increasing. A logic device is a circuit that obtains an output value by applying one or more logic inputs to certain logic operation (AND, OR, etc.). A logic circuit can be made by combining a plurality of electronic transistors.

GIST (Gwangju Institute of Science and Technology, President Kiseon Kim) School of Materials Science and Engineering Professor Gun Young Jung’s research team along with Dr. Yusin Pak’s research team at the Sensor System Research Center at the Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) developed technology for optical-logic devices that operate with light using organic and inorganic perovskite* materials.

The research team focused on optical-logic devices that use light with low physical energy loss as an input signal. For this purpose, organic and inorganic perovskite that absorbs light to generate electricity was used. They succeeded in developing a stacked perovskite optical-logic device in which two types of perovskite thin films with different light absorption spectra are stacked like a sandwich.

It has been proven that the desired binary logic operation is possible by inputting two lights of different wavelengths and intensities. Optical-logic devices using light operate only with light energy without electricity, raising expectations for the development of power-free optical computer processor chips. Logic operation is an operation applied to one or two binary numbers and refers to a system that derives a result value according to a set rule.

Existing logic devices can only perform one logic operation, but the perovskite optical-logic device developed by the research team can perform and implement five different basic logic operations with one device: AND, OR, NAND, NOR, and NOT.

Read the full article in Opli here.

 

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Circadian Lighting Pioneer Says The Science Isn’t Ready Yet

Mark Halper has an interesting article in LED’s Magazine interviewing Russell Foster, the scientist who predicted the non-visual receptors in the eye that are involved in the circadian response to light (pRGCs / ipRGCs). He says circadian lighting science isn’t ready yet, and there are too many unknowns.

Mark Halper has an interesting article in LED’s Magazine interviewing Russell Foster, the scientist who predicted the non-visual receptors in the eye that are involved in the circadian response to light (pRGCs / ipRGCs). He says circadian lighting science isn’t ready yet, and there are too many unknowns.

“We’re not ready yet,” said Foster, professor of circadian neuroscience at the University of Oxford. “We’re shuffling closely toward it, but there are major questions that remain unresolved. Yes, the toolkit is better than anything we’ve had before, but it is not the complete answer yet. We haven’t got the data to plugin.”

This is hardly what you’d expect from someone who, in the 1990s, posited the notion that certain cells in the eye’s retina receive light that has nothing to do with processing vision but has everything to do with maintaining the circadian rhythm.

Foster’s pioneering, decadelong hunch proved correct in 2002 when Brown University professor David Berson uncovered nonvisual photoreceptors, known as photosensitive retinal ganglion cells (pRGCs). Foster himself also found them soon thereafter.

“There are many critical factors — intensity, duration wavelength, time of day, task, a person’s light history, their age,” Foster pointed out. “All are really important. There’s this level of complexity, and we don’t know the answers to many of the important questions” that need answering in order to develop truly effective circadian lighting.

Read the full article here.

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UK-Funded Study Publishes “Consensus View” For Circadian Lighting Recommendations

On March 17th, 18 circadian lighting researchers published a “consensus view” of circadian lighting recommendations, titled: Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults, in the journal PLOS Biology. The authors include well-known circadian lighting researchers, George Brainard and Steven Lockley.

On March 17th, 18 circadian lighting researchers published a “consensus view” of circadian lighting recommendations, titled: Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults, in the journal PLOS Biology. The authors include well-known circadian lighting researchers, George Brainard and Steven Lockley.

Three significant aspects of the paper are:

  1. The broad consensus achieved on a set of circadian lighting recommendations in a field known for its lack of consensus, and
  2. The paper focuses on the metric of Melanopic Equivalent Daylight Illuminance (Melanopic EDI).
  3. The paper achieves agreement between researchers in North America and Europe.

Abstract

Ocular light exposure has important influences on human health and well-being through modulation of circadian rhythms and sleep, as well as neuroendocrine and cognitive functions. Prevailing patterns of light exposure do not optimally engage these actions for many individuals, but advances in our understanding of the underpinning mechanisms and emerging lighting technologies now present opportunities to adjust lighting to promote optimal physical and mental health and performance. A newly developed, international standard provides an SI-compliant way of quantifying the influence of light on the intrinsically photosensitive, melanopsin-expressing, retinal neurons that mediate these effects. This new report provides recommendations for lighting, based on an expert scientific consensus and expressed in an easily measured quantity (melanopic equivalent daylight illuminance (melaponic EDI)) defined within this standard. The recommendations are supported by detailed analysis of the sensitivity of human circadian, neuroendocrine, and alerting responses to ocular light and provide a straightforward framework to inform lighting design and practice.

The full paper can be viewed here.

Brown TM, Brainard GC, Cajochen C, Czeisler CA, Hanifin JP, Lockley SW, et al. (2022) Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLoS Biol 20(3): e3001571. https://doi.org/10.1371/journal.pbio.3001571

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Two New Sleep Studies Show Impacts Of Light On Young Children and Adults

Two new studies, one on young children, the other on adults, suggest detrimental health effects of light at night.

Light & Young Children’s Health

A recent study by a research team at the University of Colorado at Boulder suggests even slight exposure to dim light can disrupt a youngster’s sleep. The research found any type of light exposure before bed can impact the production of a hormone called melatonin. Melatonin comes from the pineal gland in the brain and impacts your circadian rhythm, a 24-hour biological clock in charge of regulating when to sleep and when to stay awake.

The research team recruited 36 children between the ages of three to five for a nine-day study where children wore wrist monitors to track their sleep and light exposure at night. The first seven days recorded the children on a stable sleep schedule to normalize their circadian rhythms and adopt a pattern where melatonin levels increase at the same time each evening.

On the eighth day, the team transformed the children’s home into “caves” where they placed black plastic on the windows to dim the lights. They also took saliva samples from each child every half hour starting in the early afternoon until after bedtime to look at when the children’s biological night began and the level of melatonin at that time.

On the last day, every child played a game on a light table one hour before bedtime, in a similar position as someone looking at a lit-up phone or tablet. The light intensity varied from five lux to 5,000 lux (one lux is equivalent to the light from a candle three feet away).

Results show exposure to light suppressed melatonin levels by 70 to 99 percent in comparison to the previous night. Unlike adults, exposure to light made a bigger difference in melatonin suppression than brightness.

Specifically, lights at five to 40 lux — dimmer than the average room — suppressed melatonin by 78 percent. Moreover, melatonin production continued to be delayed for an additional 50 minutes after exposure to light.

“Together, our findings indicate that in preschool-aged children, exposure to light before bedtime, even at low intensities, results in robust and sustained melatonin suppression,” says Lauren Hartstein, a postdoctoral fellow in the Sleep and Development Lab at CU Boulder.

Read the full article here.

 

Light & Adult Heart Health

Researchers from Northwestern University’s Feinberg School of Medicine have found sleeping in a moderately lit room can potentially harm a person’s cardiometabolic health. The study saw just one night of sleep in a room with moderate ambient light increased nighttime heart rate and spiked insulin resistance in the morning.

This new study recruited 20 healthy young adults and split them into two groups. One group spent two consecutive nights in a sleep laboratory under dim light (less than three lux), while the other group spent one night in dim light and a second night under moderate light levels (a room light at 100 lux).

Daniela Grimaldi, co-first author on the study, said her team saw heightened overnight heart rates in participants exposed to brighter light while they slept. This increased stress on the heart at night could plausibly result in declines in a person’s cardiometabolic health over the long-term, according to Grimaldi.

“We showed your heart rate increases when you sleep in a moderately lit room,” said Grimaldi. “Even though you are asleep, your autonomic nervous system is activated. That’s bad. Usually, your heart rate together with other cardiovascular parameters are lower at night and higher during the day.”

The researchers also saw increased insulin resistance in participants the morning after sleeping under moderate light. Senior author Phyllis Zee said this finding may offer clues to observational studies linking higher rates of diabetes to nighttime light exposure.

Read the full article here.

 

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LRC Proposes Two Metrics To Predict LED Product Life

Arguably, the biggest gap in LED metrics is a product lifetime metric and test procedure. Currently, the industry is rife with fraudulent emitter life claims used as LED system product life claims (lamps, luminaires, and engines).

Arguably, the biggest gap in LED metrics is a product lifetime metric and test procedure. Currently, the industry is rife with fraudulent emitter life claims used as LED system product life claims (lamps, luminaires, and engines). It is common to see LED product spec sheets with exaggerated L70 for the emitters (only), both violating of the TM-21 6X extrapolation rule, and being used as product lifetime claims.

Early last year, the Lighting Research Center (LRC) was approached by the International Energy Agency’s 4E Solid State Lighting Annex and asked to explore and summarize the literature on LED system lifetime. Over the course of a year, LRC conducted an international literature search that included definitions of LED life, failure mechanisms of LED components and systems, parameters that accelerate failure, and available test methods for estimating LED system lifetime. The results were accumulated into a report published in June by the IEA 4E SSL Annex, Literature Summary of Lifetime Testing of Light Emitting Diodes and LED Products, which is available online.

The major outcome of this report is the LRC’s recommendation of two test methods as the most promising for accurate life prediction of LED lighting products. The selection of these two methods was based on an understanding—from both the literature and from LRC’s own laboratory testing and research for the past two decades—of the ways in which LED systems fail and the operating conditions that lead to their failure. Here are the two proposed methods:

  • The first method, adopted recently by the European Union, considers both environmental condition and use pattern. This is an important advancement in the industry because it recognizes the effect of the operating conditions of LED products in different applications on lifetime. However, in its present form, this method only considers one temperature and use pattern condition and was implemented to report lumen depreciation and percentage of surviving products at the end of the test. Before this method can be used for predicting lifetime in different applications, other test conditions representative of those applications need to be added.
  • The second method was proposed by the Lighting Research Center and formalized by the Alliance for Solid-State Illumination Systems and Technologies (ASSIST). This method allows for any combination of environment temperature and use pattern to be specified, and thus provides a means to predict LED product lifetime within the boundary conditions of the test. One thing to note is that humidity is not considered in either of these test methods. Humidity was conveyed as a concerning factor in a number of studies discovered during our literature search. Considering the dominance of LED products for outdoor applications, such as for lighting parking lots, roadways, parks, airports and more, the effects of humidity should be weighed, especially where safety is concerned.

Read the full article in LD+A Online here.

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DOE Publishes Research On Connected Lighting Systems Challenges & Opportunities

In September 2021, the US Department of Energy (DOE) published a research study about how users and stakeholders engage with connected lighting systems (CLS) and make decisions during each step in the supply chain process, from production to operation, in commercial buildings in the United States.

In September 2021, the US Department of Energy (DOE) published a research study about how users and stakeholders engage with connected lighting systems (CLS) and make decisions during each step in the supply chain process, from production to operation, in commercial buildings in the United States. CLS have seen slower than expected adoption and have faced many operational and installation challenges since they were first introduced in the market.

The goal of this study was to provide an overview of:

  • The decision-making process for CLS and how/why technologies and features are selected;
  • The user experience in each step of the supply chain and the challenges faced;
  • Barriers to adoption for CLS and opportunities to address these barriers; and
  • Potential opportunities to improve the design of CLS to increase adoption and enhance usage.

Though important and influential to the CLS market, utility incentives, regulations, energy codes, and policy impacts were not a focus of the study.

The key challenges identified for CLS are:

  • Complexity and Variability
  • Experience and Relationship-Based Market
  • Contractor Apprehension and Reluctance
  • Consumer Lack of Perceived Value
  • Embedded Sensors & Controls
  • Cost Transparency
  • Interoperability

Potential opportunities identified to address these challenges are:

  • Workforce Development
  • Technical Research and Development
  • Data Collection / Field Validation
  • Market
  • Education
  • Stakeholder Engagement

Detailed research findings are available here.

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Luminaire Level Lighting Controls, Catching On or Catching Hell?

The Portland IES will feature a presentation by John Arthur Wilson of Fernhill Shopworks on Wednesday, February 16, at 11:45 am PST. Wilson will be presenting findings from his 2021 lighting controls research. The free…

The Portland IES will feature a presentation by John Arthur Wilson of Fernhill Shopworks on Wednesday, February 16, at 11:45 am PST. Wilson will be presenting findings from his 2021 lighting controls research. The free webinar is open to anyone in the industry. No pre-registration is required. Use the link below to join the Teams event :
“Luminaire Level Lighting Controls, Catching On or Catching Hell?”

His 2021 research also resulted in a learning guide that can be used to support basic education around wireless trends in lighting. NEEA has published that document on their Better Bricks website, available to the public here.

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New International Lighting Non-Profit Founded In Canada

The All Things Lighting Association (ATLA) has been founded as a non-profit organization to advance, support, promote, and contribute to innovation, science, and engineering in all fields of lighting, including architecture, health, horticulture, and entertainment.

The All Things Lighting Association (ATLA) has been founded as a non-profit organization to advance, support, promote, and contribute to innovation, science, and engineering in all fields of lighting, including architecture, health, horticulture, and entertainment. ATLA was founded with three goals:

  1. To provide ATLA S001, Standard Format for the Electronic Transfer of Luminaire Optical Data, and ATLA S001-A, Amendment to Standard Format for the Electronic Transfer of Luminaire Optical Data, Including JSON Specification, as freely-available standards for lighting industry adoption. ATLA S001 has been published as ANSI/IES TM-33-18 and (in Italian) UNI 11733:2019, and ATLA S001-A is a work product of CIE Technical Committee 2-92. If approved, ATLA S001-A will likely become a joint CIE/ISO standard. It is also under consideration by the IES as a successor to TM-33-18.
  2. To curate blog articles and other resources (such as bibliographies) on lighting research issues. Lighting research has become increasingly cross-disciplinary over the past decade or so, and it can be difficult for both researchers and lighting professionals to understand the broader scope. The articles are intended to examine specific issues and provide references to the literature that both support the presented information and offer a guide for more in-depth study. The initial postings are my blog articles from the last eight years, but peer-reviewed contributions from other authors will be welcomed.
  3. SunTracker Technologies has employed eleven university students and graduates over the past four years for its lighting-related research projects, as well as providing annual scholarships. SunTracker Technologies Senior Scientist, Ian Ashdown, has also been mentoring graduate students in a number of disciplines from North America, Europe, Africa, and India. ATLA will provide a framework to coordinate this work, including documentation, research resources, discussion, and networking, for students and others involved in lighting-related research.

For more information, click here.

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New Research Proposes A Framework For Window View Quality Within Buildings

A team of researchers have recently published new research on window views from within buildings and have proposed a new framework for designing “view quality” for window views.  The team identified three critical factors in determining view quality.

A team of researchers have recently published new research on window views from within buildings and have proposed a new framework for designing “view quality” for window views.  The team identified three critical factors in determining view quality.

  1. View Content – what’s seen through the window
  2. View Access – how much window view the occupant’s position has
  3. View Clarity – how clearly the view content can be seen

The research team propose an index for window view quality, along with design recommendations.  The full paper can be accessed here.  The paper was also published online by Leukos on 11/10/21.  The researchers are from:

  • The Center for the Built Environment, UC Berkeley
  • Berkeley Education Alliance for Research in Singapore
  • Loisos + Ubbelohde
  • California College of the Arts

#windowviews

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