Digitally controlled lighting systems equipped with colored LEDs can produce a range of different qualities of light, adjustable to users' requirements. In this context, we explore a lighting control concept which involves strategic control of RYGB LEDs forming white light, employed to increase energy efficiency. There is a fundamental trade-off between color rendering (CR) and luminous efficacy. Specifically, we can reduce CR and increase efficacy when we redistribute spectral energy intensity in favor of wavelengths where the eye response is greatest, the yellow/green region of the spectrum. The notable point is that while changing CR, the light level and color temperature can stay constant, and hence the appearance of the modified white light remains unchanged. The strategy is to bring the lighting of unoccupied spaces to minimum color rendering to save energy without altering the appearance or light levels of the illumination, when the LED system dynamically shifts to 'energy saving mode' (low CR) from 'quality mode' (high CR) according to occupancy. This paper reports and discusses the results of an ongoing research project involving the exercise of LED color mixing re-working the spectrum of white light according to this fundamental energy vs. rendering trade-off. The research work encompasses two main domains: (a) a tunable LED light source with accompanying control equipment; and (b) human factors studies concerning how surfaces and spaces are perceived under a light source with changing spectral components. Results so far have supported the two fundamental hypotheses: (a) when fully developed, color rendering modulation could potentially enable significant power reductions; (b) the majority of subjects did not detect the color rendering changes.
{"title":"Preliminary Assessment Concerning the Practical Implementation and Visual Perception of Color Rendering Modulation for Augmented Energy Savings","authors":"Maria Thompson, J. Laski, M. Chipalkatti","doi":"10.2150/JLVE.35.255","DOIUrl":"https://doi.org/10.2150/JLVE.35.255","url":null,"abstract":"Digitally controlled lighting systems equipped with colored LEDs can produce a range of different qualities of light, adjustable to users' requirements. In this context, we explore a lighting control concept which involves strategic control of RYGB LEDs forming white light, employed to increase energy efficiency. There is a fundamental trade-off between color rendering (CR) and luminous efficacy. Specifically, we can reduce CR and increase efficacy when we redistribute spectral energy intensity in favor of wavelengths where the eye response is greatest, the yellow/green region of the spectrum. The notable point is that while changing CR, the light level and color temperature can stay constant, and hence the appearance of the modified white light remains unchanged. The strategy is to bring the lighting of unoccupied spaces to minimum color rendering to save energy without altering the appearance or light levels of the illumination, when the LED system dynamically shifts to 'energy saving mode' (low CR) from 'quality mode' (high CR) according to occupancy. This paper reports and discusses the results of an ongoing research project involving the exercise of LED color mixing re-working the spectrum of white light according to this fundamental energy vs. rendering trade-off. The research work encompasses two main domains: (a) a tunable LED light source with accompanying control equipment; and (b) human factors studies concerning how surfaces and spaces are perceived under a light source with changing spectral components. Results so far have supported the two fundamental hypotheses: (a) when fully developed, color rendering modulation could potentially enable significant power reductions; (b) the majority of subjects did not detect the color rendering changes.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124925049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The performance of InGaN/YAG white LEDs for lighting applications is reviewed. Advanced small-chip-technology has achieved high-luminous efficacy white LED of almost 200lm/W by improving internal efficiency, extraction efficiency and electrical resistance. In addition, high-luminous flux device of 10,000lm by flip-chip array has been also developed by large-chip-technology.
{"title":"Performance of High-luminous Efficacy White LEDs","authors":"K. Band","doi":"10.2150/JLVE.35.192","DOIUrl":"https://doi.org/10.2150/JLVE.35.192","url":null,"abstract":"The performance of InGaN/YAG white LEDs for lighting applications is reviewed. Advanced small-chip-technology has achieved high-luminous efficacy white LED of almost 200lm/W by improving internal efficiency, extraction efficiency and electrical resistance. In addition, high-luminous flux device of 10,000lm by flip-chip array has been also developed by large-chip-technology.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116031070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Tarasenko, M. Erofeev, M. Lomaev, D. Rybka, A. N. Panchenko, E. Sosnin, V. Skakun, D. Schitz
Design and output parameters of pulse sources of spontaneous UV and VUV radiation based on the non-equilibrium discharge plasma of high-pressures gases are presented in this paper. Emission characteristics of plasma of diffuse discharge preionized by runaway electrons and barrier discharge in rare gases and mixtures of rare gases with halogens have been investigated in gases at pressure up to 15 atm at excitation power up to 100 MW/cm3. The radiant power from 4π solid angle up to 1.2 MW with pulse duration of - 8 ns on Xe2* dimers were obtained at 12 atm pressure xenon. A high-voltage (up to 150 kV) short pulsed excitation mode was tested on dielectric barrier discharge KrCl- and XeBr-excilamps.
{"title":"UV and VUV Excilamps with High Peak Power","authors":"V. Tarasenko, M. Erofeev, M. Lomaev, D. Rybka, A. N. Panchenko, E. Sosnin, V. Skakun, D. Schitz","doi":"10.2150/JLVE.35.227","DOIUrl":"https://doi.org/10.2150/JLVE.35.227","url":null,"abstract":"Design and output parameters of pulse sources of spontaneous UV and VUV radiation based on the non-equilibrium discharge plasma of high-pressures gases are presented in this paper. Emission characteristics of plasma of diffuse discharge preionized by runaway electrons and barrier discharge in rare gases and mixtures of rare gases with halogens have been investigated in gases at pressure up to 15 atm at excitation power up to 100 MW/cm3. The radiant power from 4π solid angle up to 1.2 MW with pulse duration of - 8 ns on Xe2* dimers were obtained at 12 atm pressure xenon. A high-voltage (up to 150 kV) short pulsed excitation mode was tested on dielectric barrier discharge KrCl- and XeBr-excilamps.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125329074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes a neutral point type buck converter circuit that is applicable to an electronic ballast. This circuit is a one-stage converter method electronic ballast, where circuit elements can be reduced by sharing the same switching elements by both converter and inverter circuit and still achieve high circuit efficiency. In this work, the circuit was built and experimented with a fluorescent lamp (NIPPO FLR36T6W) as output load. The proposed Electronic Ballast satisfies the IEC61000-3-2 class C harmonics standard and is suitable for lighting a fluorescent lamp.
{"title":"Electronic Ballast Using Neutral Point Type Buck Converter","authors":"N. Hidayat, Masaaki Nakamura, Y. Kato, Y. Itoh","doi":"10.2150/JLVE.35.136","DOIUrl":"https://doi.org/10.2150/JLVE.35.136","url":null,"abstract":"This paper proposes a neutral point type buck converter circuit that is applicable to an electronic ballast. This circuit is a one-stage converter method electronic ballast, where circuit elements can be reduced by sharing the same switching elements by both converter and inverter circuit and still achieve high circuit efficiency. In this work, the circuit was built and experimented with a fluorescent lamp (NIPPO FLR36T6W) as output load. The proposed Electronic Ballast satisfies the IEC61000-3-2 class C harmonics standard and is suitable for lighting a fluorescent lamp.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123276410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yoshika Takahashi, T. Katsuura, Y. Shimomura, K. Iwanaga
The prediction method of melatonin suppression values was based on previous studies related to melatonin suppression and pupil constriction. Estimated values that considered pupil constriction were larger than the actual suppression values. We focused on the pupil constriction and its correction factor to interpret the action spectrum for the properties of the melatonin suppression model. When the correction factor was used to modify the model, actual suppression values were almost completely predictable. These factors suggest that it might be possible to explain the indescribable results.
{"title":"Prediction Model of Light-induced Melatonin Suppression","authors":"Yoshika Takahashi, T. Katsuura, Y. Shimomura, K. Iwanaga","doi":"10.2150/JLVE.35.123","DOIUrl":"https://doi.org/10.2150/JLVE.35.123","url":null,"abstract":"The prediction method of melatonin suppression values was based on previous studies related to melatonin suppression and pupil constriction. Estimated values that considered pupil constriction were larger than the actual suppression values. We focused on the pupil constriction and its correction factor to interpret the action spectrum for the properties of the melatonin suppression model. When the correction factor was used to modify the model, actual suppression values were almost completely predictable. These factors suggest that it might be possible to explain the indescribable results.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"304 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129330181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daylight is natural energy used most easily in the home, and its effective use contributes to energy conservation. Therefore, the indoor environment in the morning was chosen in this research as a condition in order effectively to obtain daylight and the artificial lighting is done as a condition in order effectively to promote energy conservation. The purpose of this research is to examine the influence of illuminance by daylight that changes in time in evening and morning on the necessity of the artificial lighting and the evaluation of the atmosphere in the room. The experiment was done using a pseudo-daylight device. It has been understood that the different illuminance with the artificial lighting influences the brightness evaluation and the amount of artificial lighting felt to be necessary, and the brighter the general lighting in the room is, the higher the illuminance level at which the subject doesn't feel the need for the artificial lighting is as the amount of daylight is increasing.
{"title":"The Influence of Daylight and Artificial Lighting in the Morning on Ease of Activities and Spatial Evaluations in Living Room","authors":"M. Kunishima, M. Miyamoto","doi":"10.2150/JLVE.35.108","DOIUrl":"https://doi.org/10.2150/JLVE.35.108","url":null,"abstract":"Daylight is natural energy used most easily in the home, and its effective use contributes to energy conservation. Therefore, the indoor environment in the morning was chosen in this research as a condition in order effectively to obtain daylight and the artificial lighting is done as a condition in order effectively to promote energy conservation. The purpose of this research is to examine the influence of illuminance by daylight that changes in time in evening and morning on the necessity of the artificial lighting and the evaluation of the atmosphere in the room. The experiment was done using a pseudo-daylight device. It has been understood that the different illuminance with the artificial lighting influences the brightness evaluation and the amount of artificial lighting felt to be necessary, and the brighter the general lighting in the room is, the higher the illuminance level at which the subject doesn't feel the need for the artificial lighting is as the amount of daylight is increasing.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"25 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126069585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have designed and developed a light-source system to support advanced experiments for plant light-response studies. The light-source system consists of light-emitting diodes (LEDs) of five types: violet, blue, orange-red, red, and far-red (peak wavelengths, λp: 405, 460, 630, 660, and 735 nm). The light-source system can produce light with different compositions of the five wavelength ranges, and can provide photosynthetic photon flux densities (PPFDs) of 488 μmol m-2 s-1 for an area of 0.18 m2 at a distance of 173 mm below the LEDs. This is sufficient for the cultivation of almost all leafy vegetables and other plants that might be produced under artificial light in commercial plant factories. This report provides a technical description of the light-source system and the results of quantification tests.
{"title":"Design and Development of a Plant-Response Experimental Light-Source System with LEDs of Five Peak Wavelengths","authors":"K. Fujiwara, A. Yano, Kensuke Eijima","doi":"10.2150/JLVE.35.117","DOIUrl":"https://doi.org/10.2150/JLVE.35.117","url":null,"abstract":"We have designed and developed a light-source system to support advanced experiments for plant light-response studies. The light-source system consists of light-emitting diodes (LEDs) of five types: violet, blue, orange-red, red, and far-red (peak wavelengths, λp: 405, 460, 630, 660, and 735 nm). The light-source system can produce light with different compositions of the five wavelength ranges, and can provide photosynthetic photon flux densities (PPFDs) of 488 μmol m-2 s-1 for an area of 0.18 m2 at a distance of 173 mm below the LEDs. This is sufficient for the cultivation of almost all leafy vegetables and other plants that might be produced under artificial light in commercial plant factories. This report provides a technical description of the light-source system and the results of quantification tests.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115868166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In a system that automatically adjusts the slat angles of horizontal blinds, it is possible to allow skylight in while shielding direct sunlight. This can lead to good energy savings since it can reduce the need for artificial lighting without increasing the air-conditioning load. Our research has previously demonstrated this effect of reducing the amount of energy consumed by artificial lighting by controlling the blind slats according to the amount of skylight in an existing office building. However, it was confirmed that the occupants were dissatisfied with the system since it controlled the blinds to shut even though the occupants observed no direct sunlight and they could not clearly see out the windows. Therefore, this study was conducted with the aim of setting threshold values between the existence and non-existence of direct sunlight based on daylight conditions, so that the automatic controlling of blind slat angles would be ceased to allow slats open when they do not need to block direct sunlight.
{"title":"Study on Judging Direct Sunlight in Actual Use of Blind Slat Angle Control Systems","authors":"M. Honma, T. Kawase","doi":"10.2150/JLVE.35.67","DOIUrl":"https://doi.org/10.2150/JLVE.35.67","url":null,"abstract":"In a system that automatically adjusts the slat angles of horizontal blinds, it is possible to allow skylight in while shielding direct sunlight. This can lead to good energy savings since it can reduce the need for artificial lighting without increasing the air-conditioning load. Our research has previously demonstrated this effect of reducing the amount of energy consumed by artificial lighting by controlling the blind slats according to the amount of skylight in an existing office building. However, it was confirmed that the occupants were dissatisfied with the system since it controlled the blinds to shut even though the occupants observed no direct sunlight and they could not clearly see out the windows. Therefore, this study was conducted with the aim of setting threshold values between the existence and non-existence of direct sunlight based on daylight conditions, so that the automatic controlling of blind slat angles would be ceased to allow slats open when they do not need to block direct sunlight.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124796015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Use of LEDs in lighting applications is increasing day by day. Performance of source constructed using many LEDs depends on the placement of LEDs on source panel and their spatial and spectral characteristics. The paper reports the development of a dedicated package for analyzing and designing of LED multi-element source. Mathematical and optical modules are developed for the same using analytical equations. The tool accommodates newly developed high intensity LEDs with variable spectral and spatial responses. Further color rendering using CIE 1964 scheme is incorporated in package to give colored illuminated pattern on target. The tool is validated by testing for different source panel geometries and for variable source characteristics.
{"title":"Modeling and Simulation of Multielement LED Source","authors":"Ramane Deepa, Shaligram Arvind","doi":"10.2150/JLVE.35.34","DOIUrl":"https://doi.org/10.2150/JLVE.35.34","url":null,"abstract":"Use of LEDs in lighting applications is increasing day by day. Performance of source constructed using many LEDs depends on the placement of LEDs on source panel and their spatial and spectral characteristics. The paper reports the development of a dedicated package for analyzing and designing of LED multi-element source. Mathematical and optical modules are developed for the same using analytical equations. The tool accommodates newly developed high intensity LEDs with variable spectral and spatial responses. Further color rendering using CIE 1964 scheme is incorporated in package to give colored illuminated pattern on target. The tool is validated by testing for different source panel geometries and for variable source characteristics.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115540180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the key elements in improving lamp efficiency is understanding and controlling the halogen transport process. Therefore, it is worthwhile to build a model that depicts this process and can be applied to the study of various types of lamps. We examined the halogen transport process in a lamp by using a hybrid simulation model based on fluid dynamics and chemical equilibrium.
{"title":"Modeling of Fluid Dynamics and Thermo-Chemical System in Halogen Lamp Operation","authors":"M. Bessho, M. Ohkawa","doi":"10.2150/JLVE.35.7","DOIUrl":"https://doi.org/10.2150/JLVE.35.7","url":null,"abstract":"One of the key elements in improving lamp efficiency is understanding and controlling the halogen transport process. Therefore, it is worthwhile to build a model that depicts this process and can be applied to the study of various types of lamps. We examined the halogen transport process in a lamp by using a hybrid simulation model based on fluid dynamics and chemical equilibrium.","PeriodicalId":311488,"journal":{"name":"Journal of Light & Visual Environment","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122024061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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