Initial Results From an Experimental Hybrid Solar Lighting System in a Commercial Building and Overview of Related Value Propositions

Solar Energy ◽  
2003 ◽  
Author(s):  
Jeff Muhs ◽  
Duncan Earl ◽  
Dave Beshears ◽  
Curt Maxey
Keyword(s):  
Optical Fibers ◽  
Electrical Power ◽  
Color Space ◽  
Color Temperature ◽  
Atmospheric Conditions ◽  
Lighting System ◽  
Commercial Building ◽  
Preliminary Results ◽  
Value Propositions ◽  
Solar Lighting

This paper describes preliminary results from research on a new hybrid solar lighting (HSL) system being developed to reduce electric lighting in commercial office buildings. A physical description of HSL system components along with preliminary results from an experimental system deployed in a commercial building in Knoxville, TN are provided. Results from a systems-level, chromaticity model are compared with experimental data. A total lumen distribution efficiency of over 50% was recorded for the initial prototype having optical fibers an average of 6 m (19.5 ft) in length. The total electrical power displacement of the 1 m2 HSL proof-of-concept prototype is estimated to be between 522–2350 watts per 1000 W/m2 of incident solar radiation on the collector depending on the type of electric lights being used in conjunction with the solar lighting system. By adding the reductions in heat gain associated with reduced electric lamp use and predicted performance improvements achieved by a system redesign, the electrical power displaced in a commercial prototype could rise to between 702–3160 W (peak)/m2 of collected sunlight not including any additional electrical power that can be generated using the otherwise wasted IR energy. The color temperature of the distributed sunlight emerging from the optical fibers is approximately 5100°K and the chromaticity values in uniform color space (u′v′) are approximately (.2010, .4977). These values match well with modeled results and will vary slightly depending on the day, time, atmospheric conditions, and system configuration. The paper concludes with a discussion of new value propositions that HSL provides architects, energy providers, building owners, and occupants and briefly outlines anticipated disadvantages.

scholarly journals Melt-Spun Photoluminescent Polymer Optical Fibers for Color-Tunable Textile Illumination

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1740
Author(s):  
Konrad Jakubowski ◽  
Manfred Heuberger ◽  
Rudolf Hufenus
Keyword(s):  
Energy Transfer ◽  
Optical Fibers ◽  
Color Space ◽  
Emission Spectra ◽  
Wide Range ◽  
Color Tunable ◽  
Melt Spun ◽  
Polymer Optical Fibers ◽  
Collective Emission ◽  
Down Conversion

The increasing interest in luminescent waveguides, applied as light concentrators, sensing elements, or decorative illuminating systems, is fostering efforts to further expand their functionality. Yarns and textiles based on a combination of distinct melt-spun polymer optical fibers (POFs), doped with individual luminescent dyes, can be beneficial for such applications since they enable easy tuning of the color of emitted light. Based on the energy transfer occurring between differently dyed filaments within a yarn or textile, the collective emission properties of such assemblies are adjustable over a wide range. The presented study demonstrates this effect using multicolor, meltspun, and photoluminescent POFs to measure their superimposed photoluminescent emission spectra. By varying the concentration of luminophores in yarn and fabric composition, the overall color of the resulting photoluminescent textiles can be tailored by the recapturing of light escaping from individual POFs. The ensuing color space is a mean to address the needs of specific applications, such as decorative elements and textile illumination by UV down-conversion.

scholarly journals Evaluation of a large dish-type concentrator solar lighting system for underground car park

2018 ◽  
Vol 42 (6) ◽  
pp. 2234-2245 ◽  
Author(s):  
Duofu Song ◽  
Hui Lv ◽  
Jun Liao ◽  
Wenjuan Huang ◽  
Sihao Huang ◽  
...  
Keyword(s):  
Lighting System ◽  
Car Park ◽  
Solar Lighting

Experimental Investigation of the Impact of Biogas on a 3 kW Micro Gas Turbine FLOX®-Based Combustor

2020 ◽  
Author(s):  
Hannah Seliger-Ost ◽  
Peter Kutne ◽  
Jan Zanger ◽  
Manfred Aigner
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Waste Heat ◽  
Electrical Power ◽  
Atmospheric Conditions ◽  
Micro Gas Turbine ◽  
Fuel Mixtures ◽  
Carbon Dioxide Co2 ◽  
Electrical Power Output ◽  
The Impact

Abstract The use of biogas has currently two disadvantages. Firstly, processing biogas to natural gas quality for feeding into the natural gas grid is a rather energy consuming process. Secondly, the conversion into electricity directly in biogas plants produces waste heat, which largely cannot be used. Therefore, a feed-in of the desulfurized and dry biogas to local biogas grids would be preferable. Thus, the biogas could be used directly at the end consumer for heat and power production. As biogas varies in its methane (CH4) and carbon dioxide (CO2) content, respectively, this paper studies the influence of different biogas mixtures compared to natural gas on the combustion in a FLOX®-based six nozzle combustor. The single staged combustor is suitable for the use in a micro gas turbine (MGT) based combined heat and power (CHP) system with an electrical power output of 3 kW. The combustor is studied in an optically accessible atmospheric test rig, as well as integrated into the MGT system. This paper focuses on the influence of the admixture of CO2 to natural gas on the NOX and CO emissions. Furthermore, at atmospheric conditions the shape and location of the heat release zone is investigated using OH* chemiluminescence (OH* CL). The combustor could be stably operated in the MGT within the complete stationary operating range with all fuel mixtures.

scholarly journals Impact of different standard lighting sources on red jadeite and color quality grading

2019 ◽  
Vol 23 (4) ◽  
pp. 371-378
Author(s):  
Xin Pan ◽  
Ying Guo ◽  
Ziyuan Liu ◽  
Zikai Zhang ◽  
Yuxiang Shi
Keyword(s):  
Light Source ◽  
Color Space ◽  
Sample Surface ◽  
Color Temperature ◽  
Integrating Sphere ◽  
Light Sources ◽  
Light Spectrum ◽  
Fisher Discriminant Analysis ◽  
Fisher Discriminant ◽  
Quality Grading

The purpose of this paper is to investigate the standard light source for grading and displaying the color of red jadeite and to classify the color. With Raman spectrometer, ultraviolet-visible spectrophotometer and X-ray fluorescence spectrometer, the results show that, the Fe 3+ is the main chromogenic mineral of red jadeite, which negatively correlates with the tonal angle, while the color of red jadeite has a positive correlation with the hematite content. The color of 120 red jadeite samples was examined by collecting the reflective signaled from the sample surface using an integrating sphere with the portable X-Rite SP62 spectrophotometer based on CIE 1976 L*a*b* uniform color space. The color parameters of jadeite samples under D65, A and CWF standard light sources were analyzed. The light spectrum of D65 light source is continuous, relatively smoothed with high color temperature, which makes the sample color close to that under the natural light and can be used as the best evaluation light source. A light source contributes to improve the red tone of jadeite, which is the best light source for commercial display of red jadeite. CWF light source can be used as the auxiliary lighting for color evaluation. The color of red jadeite is divided into five levels from best to worst using K-Means cluster analysis and Fisher discriminant analysis under D65 light source: Fancy Vivid, Fancy Deep, Fancy Intense, Fancy dark and Fancy.

Efficient Optical Couplings for Fiber-Distributed Solar Lighting

Solar Energy ◽  
2003 ◽  
Author(s):  
L. C. Maxey ◽  
M. R. Cates ◽  
S. L. Jaiswal
Keyword(s):  
Optical Fibers ◽  
Optical Waveguides ◽  
Large Core ◽  
Index Matching ◽  
Refractive Index Matching ◽  
Solar Lighting ◽  
The Individual ◽  
Insertion Losses ◽  
The Impact ◽  
Loss Mechanisms

Optical couplings in large core optical waveguides have many similarities with those in conventional optical fibers but pose some unconventional challenges as well. The larger geometry, looser manufacturing tolerances and reduced dimensional stability compound the problems associated with making low-loss couplings in large core waveguides. The individual factors contributing to coupling losses are discussed to develop an understanding of the extant loss mechanisms. Individual methods and materials employed to mitigate the impact of each of the dominant loss mechanisms are discussed in detail. A combination of endface geometry control, axial alignment constraint and refractive index matching are employed to produce highly efficient optical couplings in large core waveguides. The combination of these elements has significantly reduced the insertion losses due to connector couplings. Prior to implementing the current methods losses of 15% and greater were common but these have been reduced to 2%–5% with the current methods.

Cost-Effective Light-Mixing Module for Solar-Lighting System Appended With Auxiliary RGBW Light-Emitting Diodes

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
An Chi Wei ◽  
Shih Chieh Lo ◽  
Ju-Yi Lee ◽  
Hong-Yih Yeh
Keyword(s):  
Light Source ◽  
Light Emitting Diodes ◽  
Cylindrical Tube ◽  
Cost Effective ◽  
Lighting System ◽  
Optical Efficiency ◽  
Light Emitting ◽  
Solar Lighting ◽  
Lighting Systems ◽  
Main Components

A light-mixing module consisting of a compound parabolic concentrator (CPC) and a light-mixing tube is proposed herein to realize a uniform and efficient solar-lighting system. In this lighting system, the sunlight collected into a fiber and then guided to an indoor destination is the principal light source, while an auxiliary light source including multiple red, green, blue, and white (RGBW) light-emitting diodes (LEDs) is controlled by an auto-compensating module. To mix the principal and the auxiliary sources and to realize the uniform illumination, the light-mixing tube was coated with BaSO4 and optimized as a cylindrical tube. The design of the light-mixing tube is described and discussed in this article. According to the simulated results, the uniformity and the optical efficiency of the designed light-mixing tube are 82.9% and 85.7%, respectively, while from the experimental results, the uniformity of 85.9% and the optical efficiency of 83.3% have been obtained. In terms of the common indoor-lighting standards and the specifications of commercial components used in lighting systems, the proposed light-mixing module has demonstrated the high uniformity and acceptable optical efficiency. Additionally, since the main components of the light-mixing module can be designed as plastic optics, a cost-effective light-mixing module and a profitable lighting system can be realized. Thus, the performance and the price of the proposed light-mixing module fit the demands of the illumination market, while the proposed system shows the potential for indoor solar-lighting applications.

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