Development and effect analysis of circadian rhythm-assisted LED lighting for reproducing short-wavelength ratio characteristics of natural light

2021 ◽  
pp. 002072092098848
Author(s):  
Seung-Taek Oh ◽  
Jae-Hyun Lim
Keyword(s):  
Circadian Rhythm ◽  
Short Wavelength ◽  
Animal Experiment ◽  
Color Temperature ◽  
Natural Light ◽  
Effect Analysis ◽  
Led Lighting ◽  
Artificial Lighting ◽  
Lighting Control ◽  
Lighting Environment

The short-wavelength ratio of natural light that changes a day cycle helps maintain the circadian rhythm. The circadian rhythm is a phenomenon in which the flow of physical activity is repeated every 24 hours and is synchronized mainly by natural light. However, since people's exposure time to artificial lighting has increased recently, the issue of circadian rhythm imbalance has been raised, and lighting techniques for reproducing the color temperature or wavelength characteristics of natural light have been proposed. There has not been any case for the short-wavelength ratio cycle reproduction of natural light close to the circadian rhythm; thus, a circadian rhythm-assisted LED light that reproduces the short-wavelength ratio of natural light for one day is presented in this paper, and its effect is confirmed through animal experiment. After the lighting control standard is derived through the analysis of natural light characteristics, its periodic short-wavelength ratio is realized through the control of each LED lighting channel. Subsequently, rat-based animal experiment is conducted to analyze the amount of melatonin, a major factor in circadian rhythm. The results confirm that the proposed lighting environment has higher melatonin levels by about 17% (day7) and 24% (day14) compared with the general lighting environment.

Development of a natural light reproduction system for maintaining the circadian rhythm

2019 ◽  
Vol 29 (1) ◽  
pp. 132-144 ◽  
Author(s):  
Kyeong-Mi Kim ◽  
Young-Won Kim ◽  
Seung-Taek Oh ◽  
Jae-Hyun Lim
Keyword(s):  
Circadian Rhythm ◽  
Short Wavelength ◽  
Optical Measurement ◽  
Light Emitting Diode ◽  
Natural Light ◽  
Light Cycle ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Reproduction System ◽  
Lighting Environment

Circadian rhythm is linked to sleep, arousal and human health overall, affecting body temperature and heart rate. A 24-h natural-light cycle provides optimum lighting environment for humans. However, as people increasingly stay indoors with artificial lighting, lacking periodic characteristics, imbalance in the circadian rhythm ensues. Previous lighting-related studies to resolve such problem partially provided the colour temperatures of natural light but failed to reproduce the 24-h periodic characteristics of it. This study proposes a natural light-reproducing system that provides the daylight cycle characteristics of natural light in order to maintain the circadian rhythm. Natural light was measured through an optical measurement equipment, while the characteristics (colour temperature and short-wavelength ratio) of natural light by season and time were analysed. Subsequently, the control indicator of seasonal and hourly lighting was extracted and applied to the light-emitting diode lighting to provide lighting service, executing a daylight cycle that reflects the characteristics of natural light. After the sunset, especially, the circadian rhythm was maintained by minimizing the short-wavelength ratio of the lighting while maintaining indoor illumination.

scholarly journals Method of Calculating Short-Wavelength-Ratio-Based Color Temperature Supporting the Measurement of Real-Time Natural Light Characteristics through RGB Sensor

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6603
Author(s):  
Seung-Taek Oh ◽  
Geon-Woo Jeon ◽  
Jae-Hyun Lim
Keyword(s):  
Real Time ◽  
Short Wavelength ◽  
Measuring Equipment ◽  
Measurement Methods ◽  
Color Temperature ◽  
Average Error ◽  
Natural Light ◽  
Average Error Rate ◽  
Chromaticity Coordinates ◽  
Specialized Measuring

The characteristics of natural light are mostly collected through specialized measuring equipment, such as a spectroradiometer, and some suggested measurement methods through a small RGB sensor. However, specialized measuring equipment presents difficulty in its high cost, and the RGB-sensor-based method has the limitation of being unable to measure the wavelength characteristics of natural light that are needed to implement lighting that supports circadian rhythms. This paper presents a method for calculating the short-wavelength-ratio-based color temperature of natural light in real time. First, an analysis of the correlation between the characteristics of natural light collected through a spectroradiometer was performed to determine the factors that were needed to accurately measure the color temperature of natural light. Then, the short-wavelength ratio of natural light was calculated through chromaticity coordinates (x and y), which are output values of the RGB sensor, and an equation for calculating the color temperature of natural light was derived through the short-wavelength ratio. Furthermore, after producing an RGB-sensor-based device, the derived equation was applied to calculate the color temperature of real-time natural light that reflects the wavelength characteristics. Then, as a result of the performance evaluation of the proposed method, the color temperature of natural light was accurately calculated within 1% of the average error rate.

The Color Temperature Flexibility-typed LED Lighting Control System

2015 ◽  
Vol 64 (2) ◽  
pp. 284-288
Author(s):  
Hye-Myeong Kim ◽  
Woo-Seok Yang ◽  
Young-Seek Cho ◽  
Dae-Hee Park
Keyword(s):  
Control System ◽  
Color Temperature ◽  
Led Lighting ◽  
Lighting Control

scholarly journals Application of color temperature controllability in LED lighting environment of highway tunnel

2021 ◽  
Vol 233 ◽  
pp. 01101
Author(s):  
Zhiqiang Liu ◽  
Peifeng Li ◽  
Haifeng Jiang ◽  
Dan Wang
Keyword(s):  
Light Source ◽  
Visual Recognition ◽  
Control Function ◽  
Light Environment ◽  
Color Temperature ◽  
Led Lighting ◽  
Led Light ◽  
Dimming Control ◽  
Lighting Environment ◽  
Light Color

In recent years, tunnel LED lighting has been widely used in tunnel lighting engineering because of its advantages such as fast start, low energy consumption and good light color controllability. However, at present, the tunnel LED lighting mostly adopts the single dimming control function of light brightness, which does not give full play to the technical advantages of the tunnel LED lighting with two indicators of light brightness and light color temperature control, and does not consider the influence of the color temperature and spectral distribution of the LED light source on the safety and comfort of the tunnel LED lighting environment. Therefore, this paper studies the relationship between the color temperature of tunnel LED lighting source and the visual comfort and visual recognition distance, analyzes the actual impact of the color temperature of LED light source on the tunnel lighting light environment, and puts forward the color temperature index applicable to the entrance and exit sections of tunnel LED lighting, which provides a theoretical basis for building a safe and comfortable "two types" tunnel LED lighting light environment.

scholarly journals Sustainable Lighting for High-Rise Buildings: Lighting Solutions for High-Rise Buildings in the Context of Sustainability

2019 ◽  
Vol 3 (2) ◽  
pp. 1
Author(s):  
Jonas J Becker
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Lighting Design ◽  
Project Planning ◽  
Natural Light ◽  
Artificial Lighting ◽  
Sustainable Solutions ◽  
Health And Wellbeing ◽  
High Rise ◽  
High Rise Building

As awareness about Human Centric Lighting rises sustainable lighting concepts in high-rise architecture are more and more considered. Health and wellbeing are terms that become an essential part in light planning. The question is if there are sustainable solutions to improve this problem and if so how to implement them in the lighting planning of a modern high-rise building properly? And is there potential for improvement in sustainability of lighting solutions when it comes to working or living conditions? Two main sources of light are looked at: Daylight and artificial lighting. In the case of a modern high-rise building the lighting design necessarily consists of them both. However, the conclusions of the researches looked at in this paper show that it is of utmost importance of how this technology is applied. My findings show that melanopic effective lighting has the power to coordinate our circadian rhythms. Lighting solutions for daytime can positively influence our circadian rhythm by the consideration of natural light in project planning as well as the use of intelligent artificial lighting solutions such as the ones done research on. Keywords: sustainable lighting, human centric lighting, high rise building

Review of the Current State and Future Development in Standardizing Natural Lighting in Interiors

2018 ◽  
pp. 5-26 ◽  
Author(s):  
Stanislav Darula
Keyword(s):  
Human Life ◽  
Natural Light ◽  
Artificial Lighting ◽  
Computer Tools ◽  
Natural Lighting ◽  
Current State ◽  
Minimum Requirements ◽  
Life On Earth ◽  
Window Design

Three elements mainly wind, water and sun seemed to determine in ancient ages the basic phenomena of life on Earth. Architectural history documented the importance of sun influence on urban and building construction already in layouts of Mesopotamian and Greek houses. Not only sun radiation but especially daylight played a significant role in the creation of indoor environment. Later, in the 20th century, a search of interaction between human life in buildings and natural conditions were studied considering well­being and energy conscious design recently using computer tools in complex research and more detail interdisciplinary solutions. At the same time the restricted daytime availability of natural light was supplemented by more efficient and continually cheaper artificial lighting of interiors. There are two main approaches to standardize the design and evaluation of indoor visual environment. The first is based on the determination of the minimum requirements respecting human health and visibility needs in all activities while the second emphasizes the behaviour and comfort of occupants in buildings considering year­around natural changes of physical quantities like light, temperature, noise and energy consumption. The new current standardization basis for daylight evaluation and window design criteria stimulate the study of methodology principles that historically were based on the overcast type of sky luminance pattern avoiding yearly availability of sky illuminance levels. New trends to base the daylight standardization on yearly or long­term availability of daylight are using the averages or median sky illuminance levels to characterise local climatological conditions. This paper offers the review and discussion about the principles of the natural light standardization with a short introduction to the history and current state, with a trial to focus on the possible development of lighting engineering and its standards in future.

scholarly journals A Supervisory Control Strategy for Improving Energy Efficiency of Artificial Lighting Systems in Greenhouses

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 202
Author(s):  
Gianluca Serale ◽  
Luca Gnoli ◽  
Emanuele Giraudo ◽  
Enrico Fabrizio
Keyword(s):  
Control Strategy ◽  
Light Emitting Diode ◽  
Cost Savings ◽  
Energy Performance ◽  
Lighting System ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Lighting Control ◽  
Lighting Systems ◽  
Power Densities

Artificial lighting systems are used in commercial greenhouses to ensure year-round yields. Current Light Emitting Diode (LED) technologies improved the system efficiency. Nevertheless, having artificial lighting systems extended for hectares with power densities over 50W/m2 causes energy and power demand of greenhouses to be really significant. The present paper introduces an innovative supervisory and predictive control strategy to optimize the energy performance of the artificial lights of greenhouses. The controller has been implemented in a multi-span plastic greenhouse located in North Italy. The proposed control strategy has been tested on a greenhouse of 1 hectare with a lighting system with a nominal power density of 50 Wm−2 requiring an overall power supply of 1 MW for a period of 80 days. The results have been compared with the data coming from another greenhouse of 1 hectare in the same conditions implementing a state-of-the-art strategy for artificial lighting control. Results outlines that potential 19.4% cost savings are achievable. Moreover, the algorithm can be used to transform the greenhouse in a viable source of energy flexibility for grid reliability.

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