Post on 26-Dec-2015
Energy-efficient Daylighting Systems for Multi-story Buildings
International Conference on Modeling and Simulation 2013
Irfan Ullah Department of Information and Communication Engineering Myongji university, Yongin, South Korea
Copyright © solarlits.com
Energy and Buildings, vol. 72, pp. 246-261, 2014. http://dx.doi.org/10.1016/j.enbuild.2013.12.031
Contents
1. Introduction2. Objective3. Background4. Proposed system
a) Parabolic troughb) Linear Fresnel lens
5. Light transmission and distribution6. Simulation and results7. Conclusions and Future Work
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• Energy consumption• In South Korea, 46% of total energy is used in buildings (EIA 2007)• In buildings, 40–50% of total energy is consumed for electric lighting
Introduction
2/27
CO2 emissions by regionInternation energy agency (IEA), 2009
IEA annual energy reviews, 2011
Introduction
3/27
Annual energy outlook 2011 (EIA, U.S.)
• Artificial lighting cannot fulfill the needs of the human body• Required Vitamin D3 (Ultraviolet light)• 15% of office workers complain of eye strain
• Daylight improves • Patient recovery• Worker productivity
• Daylight can reduce• Seasonal affective disorder (SAD)
Benefits of daylight
Wavelength (nm)Electromagnetic spectrum4/27
Daylighting
• Daylighting• To illuminate interior by sunlight• Daylighting system (active and passive)• Capturing (reflectors and lenses)• Transmission (light pipe and optical fiber)• Distribution (lenses and diffusers)• Hybrid daylighting system• Daylight + Artificial light
5/27
“Daylight building can reduce electric lighting energy consumption by 50–80%” (U.S. Green Building Council)
Overview of daylighting
Background
Microstructured daylighting system
• Sunlight transmission through• Window• Low-efficiency• Difficult to implement
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Background
Tabular guidance system Core daylighting system
• Sunlight transmission through• Light pipe and light guide• Low-efficiency• Nonuniform illumination
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Prismatic light guide
Background
Himawari daylighting system Parans fiber optic daylighting system
• Sunlight transmission through• Optical fiber• Costly (large amount of modules)
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Objective
• Highly concentrated sunlight through• Parabolic trough• Linear Fresnel lens
• Delivering sunlight in the interior• Large-scale building interiors• Multi-floor buildings
• Uniform illumination at• Capturing stage• Distribution stage
• Reducing electric lighting power consumption in buildings
9/27
Parabolic trough
Linear Fresnel lens
Proposed System
10/27
Flow diagram of the hybrid daylighting system
Compound parabolic concentrator (CPC)
Hardware design of daylighting systems
Design using CPC for the parabolic trough
Design using CPC for the linear Fresnel lens
11/27
Light concentration
Non-imaging concentratorCompound parabolic concentrator (CPC)
Ray-tracing of daylighting systems
12/27
Parabolic trough with parabolic reflector to make collimated light for optical fibers
Linear Fresnel lens with plano-concave lens to make collimated light for optical fibers
Measurements for Parabolic trough
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With trough CPCWithout trough CPC a : Diameter of entry aperture
a' : Diameter of exit aperture
θi : Maximum input angle
HPR : Rectangular aperture height
Wr : Width of receiver
To make collimated light
Measurements for linear Fresnel lens
14/27
With trough CPCWithout trough CPC
Wp : Width of plano-concave lens
Wr : Width of receiver
r : Radius
n : Refractive index
NA : Numerical aperture
D: Diameter of collimating lens
f: focal length of the lens
Focal length of Fresnel lens
To insert all light into fibers
Light Transmission
• Area of each floor = 10x6 m• Silica optical fiber (SOF)• Length of single SOF = 130 mm• Plastic optical fiber (POF)• Length of single POF = 6 m• Total fiber = 285
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Optical fibers with index matching
2 mm
1.98 mm POF SOF 1.457 mm
1.8 mm
SOFncladding = 1.40ncore = 1.457
POFncladding = 1.40ncore = 1.49
Refractive index
Efficiency of POF = 80% for 6m length
Light Distribution
• One bundle = 19 optical fibers• Light distribution• Biconcave lens• Combination of lenses
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Single lens
Combining two lensesBundle of optical fibers
Economics
• Cost of parabolic trough = $400• Cost of linear Fresnel lens = $200• Cost of tracking modules = $400
• Total optical fibers = 285• Total length of SOF = 33.28 m• Cost of SOF = $1.2/m• Total cost of SOFs = $ 44
• Total length of POF = 1330 m• Cost of POF = $0.514/m• Total cost of POFs = $ 684
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Interior view
18/27
Floor plan of test room
• 15 bundles of optical fibers• 15 LED light sources
Section view of room’s interior
Daylighting simulation
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Light source and surface to measure illuminance
• Daylighting simulation• LightTools®, DIALuxTM, and SolidWorksTM
• Illuminance on the surface
Outdoor average illuminance
dS : Surface areadF : Luminus flux on the surface
Illuminance (lx)
Uniform illumination
20/27
• Uniform illumination into optical fibers
Parabolic trough
Linear Fresnel lensCandle power distribution curveEncircled energy of fiber bundle
Illuminance on work plane
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Daylight illuminance distribution on the work plane for (a) parabolic trough and (b) linear Fresnel lens
(a) (b)
Interior View
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Indoor lighting simulationDaylight distribution in the interior
Illuminance and Uniformity
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Daylight average illuminance on the work plane
Uniformity on the floor
Uniformity on the work plane
Hybrid daylighting system
• LED light• OSRAMTM LW-W5AM, 130 lm/W• 26 LEDS with a reflector • Achieving illuminance of 500 lx all times
24/27LEDs with parabolic reflector
LEDs’ illuminance distribution
Hybrid daylighting system
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Daylight and LEDs’ illuminance distribution
Conclusions
• Highly concentrated light• Parabolic trough • Linear Fresnel lens
• Solution of high concentration by CPC• Uniform illumination into optical fibers• Illumiated large-scale building interior• Multi-floor buildings
• Increased light quality• Illuminance of more than 500 lx all time• Can save about 40% energy
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Future work
• Installing system for multi-floor building• Transmitting light at long distance
• Optical fiber • Light pipe
• Integrated solar cells
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Parabolic trough Linear Fresnel lens
References
1. A. Rosemann, G. Cox, P. Friedel, M. Mossman, and L. Whitehead, “Cost-effective controlled illumination using daylighting and electric lighting in a dual-function prism light guide,” Light. Res. Tech. 40, 77-88 (2008).
2. C. Tsuei, W. Sun, and C. Kuo, “Hybrid sunlight/LED illumination and renewable solar energy saving concepts for indoor lighting,” Opt. Express 18, A640-A653 (2010).
3. V. E. Gilmore, “Sun flower over Tokyo,” Popular Science, Bonnier Corporation, America, 1988.
4. D. Feuermann, J. M. Gordon, “SOLAR FIBER-OPTIC MINI-DISHES: A NEW APPROACH TO THE EFFICIENT COLLECTION OF SUNLIGHT,” Sol. Energy. 65, 159-170 (1999).
5. D. Feuermann, J. M. Gordon, M. Huleihil, “Solar fiber-optic mini-dish concentrators: first experimental results and field experience,” Sol. Energy. 72, 459-472 (2002).
6. A. Kribus, O. Zik, J. Karni, “Optical fibers and solar power generation,” Sol. Energy. 68, 405-416 (2000).
7. C. Kandilli and K. Ulgen, “Review and modelling the systems of transmission concentrated solar energy via optical fibres,” Renewable and Sustainable Energy Reviews, 13, 67-84 (2009).
8. I. Ullah and S. Shin, “Development of Optical Fiber-Based Daylighting System with Uniform Illumination,” J. Opt. Soc. Korea 16, 247-255 (2012).
9. I. Ullah and S. Shin, "Uniformly Illuminated Efficient Daylighting System," Smart Grid and Renewable Energy, Vol. 4, No. 2, pp. 161-166 (2013).
Irfan UllahDept. of Info. and Comm. EngineeringMyongji University, Yongin, South KoreaEmail: irfan@mju.ac.krHomepage: sl.avouch.org
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