LED IMPLEMENTATION RESEARCH

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					LED (light emitting diodes) IMPLEMENTATION RESEARCH
Duke Smart House By: Michael McGrail December 2005

Reason For Research
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Determine quality/economical qualities of LEDs; is it practical to illuminate whole rooms in the house with this lighting technology? Find out the trends in LED technology and see where it can best be applied in the Duke Smart House Future projects for the smart house house

What are LEDs?
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LEDs are semiconductor technology that emits light at the junction of oppositely charged materials when voltage forces electron movement Electrons’ moving from negative side causes photons to be released when they fill in “holes” on positive side Temperature in LED unit can get HOT, but VERY little heat is dissipated from light LEDs have life of up to 100,000 hours (50,000 hours for some white LEDs) LEDs work over wide range of outdoor temperature (even cold!)

Light Facts
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Lights consume ~7.5% of energy use in homes Average 75 Watt incandescent bulb can cost ~$21 to operate per year @~$0.075 per kWh Incandescent bulb can last 1000 – 2000 hours and cost ~<$1 Fluorescent bulbs can yield similar output at fraction of energy cost per year (@ 33 Watts Compact Fluorescent puts out similar lumens as 100W incandescent bulb) This means the higher purchase cost of fluorescent bulbs can be paid back over its lifetime (mostly in energy savings) Compact Fluorescent bulbs cost ~$2-3, while larger ones can cost from a couple dollars to over ~$20 Fluorescent bulbs last ~ 10 times longer than incandescent bulbs LEDs have even longer life: up to 100,000 hours (50,000 hours for some white LEDs) LED costs depend on unit and light output (see examples on later slide)

Lighting Numbers
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One way to describe the efficiency and output of a particular light type is by using its LUMENS / WATT value (light output / energy used) To give a reference point to work from: Incandescent bulbs average: 15 lm/W Compact Fluorescent average: 50’s to low 60’s lm/W example: Energy Star Compact Fluorescent uses 66% less energy (~33 Watts) than a 100 Watt incandescent bulb, yet gives a similar lumen output

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Typical Light Numbers for Room Illumination
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60 Watt Incandescent light bulb gives off ~800 lumens 75 Watt Incandescent light bulb gives off ~1100 lumens 100 Watt Incandescent light bulb gives off ~1600 lumens Compact Fluorescent bulb (~33W Energy Star) gives off ~1600 lumens

Can WHITE LED’S Provide Efficient Room Illumination?
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To sum up research: NOT QUITE YET Though technology is rapidly advancing, efficient room illumination is not yet commercially available Currently, white LED illumination devices being sold have lumen per watt values into the 30’s, but do not have the ability to put out sufficient amount of lumens for room illumination

White LED Lumen Output
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As seen with incandescent and compact fluorescent, lumen output values between 800 and 1600 would be ideal for room illumination Therefore, some of the top white LED lighting systems which yield ~20, ~100, to ~360 lumens (many clustered small LEDs) will not produce enough output

Purchase Costs & Energy Consumption
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Prices for white LEDs range from ~$12 to over $100 per LED unit, depending on type and lumen output Energy usage is 1 Watt to 5 – 7 Watts

WHAT DOES THIS ALL MEAN?
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To bring this part of the analysis together, white LED’s should only be used to illuminate a small area over long periods of time (especially where color rendering is of importance)

How Should This Apply to Duke Smart House?
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This technology could be useful in the following areas: - Doorways - Hallways - Kitchen Counters - Workbenches - Hard to reach areas where changing lights would be difficult - Pathways (outside) - Vibration (shock) heavy areas (mechanical room)

Technologies Seen During Research
Company:
LumiLEDs Dialight

Product:
Luxeon Star Warm White

Energy Usage:
~1 Watt(s)

Cost:
~$12

Lumen Output: ~20

Description:
Single larger LED

Edison Base Lamp (White)
R30 123 Edison Base Indoor/ Outdoor Floodlight LED Bulb

~5 Watts

~$135

~120

Looks like light bulb

Ledtronics

~6-7 Watts

~$100

~365

123 small LEDs Clustered together

Data from company websites and seller websites – Information subject to change

WARNING
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Though LEDs do not emit much heat from light source, actual LED unit may become very hot, even at dangerous levels – Heat sinking is a concern for this technology – Use at own risk

Future Advancing LED’s - Cree SBTC and LBNL Research
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Research funded by: BT / NETL SSL Successfully obtained lumens per watt 50 – 60 range Developed 67 lumens at 57 lm/W with single LED chip Compact lamp prototypes of ~1200 lumen output with >40 lm/W (multiple LEDs) In terms of packaging technology, a 800 lumen output lamp was developed at ~40lm/W (to see how design affected light output and heat dissipation)

This means…
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White LED for room illumination is possible in the near future Package design for LEDs to handle heat and light projection will help bring technology out commercially Likely to be costly, but competition will help drive down cost for this energy saving, long life technology

Possible Projects for House
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Have LED team monitor trends in technology and contact leading manufactures to possible implement best approved technology Have team research what rooms could benefit from this technology

Breaking News
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Accidental discovery at Vanderbilt University by Michael Bowers showed a way to use quantum dots mixed in coating over blue LED’s to create white light similar to incandescent bulb Visit school website for details

Cited Sources:
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Cited Sources: (these include some specification sheets from certain manufactures) Sylvania Lighting package (40 Watt) incandescent 1000 hour http://www.energystar.gov/index.cfm?c=cfls.pr_cfls http://www.consumerspower.org/home_energy/lighting.php http://msnbc.msn.com/id/9399209/from/RL.1/ http://msnbc.msn.com/id/9777070/from/RL.1/ http://www.eere.energy.gov/consumer/tips/appliances.html http://www.eere.energy.gov/consumer/tips/home_energy.html http://www.eere.energy.gov/consumer/tips/lighting.html http://www.lrc.rpi.edu/programs/Futures/LF-LEDs/index.asp http://www.eco-labels.org/greenconsumers/energy.cfm http://www.technologyreview.com/InfoTech/wtr_12185,294,p1.html http://www.worldchanging.com/archives/003669.html http://www.otherpower.com/otherpower_lighting.html http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/led/abstract.asp http://www.eere.energy.gov/femp/energy_expo/2005/pdfs/t_s6a.pdf - 2433.4KB By: Gary R. Durgin http://www.netl.doe.gov/ssl/faqs.htm http://www.netl.doe.gov/ssl/portfolio-05/WhiteLEDPackageEfficiency.htm http://www.eere.energy.gov/buildings/info/documents/pdfs/ ee_lightingvolII.pdf

By: Eugene Hong, L.C. - Louise A. Conroy - Michael J. Scholand

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http://www.luxeonstar.com/sub_category.php?id=208&link_str=208 http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/searchPage2.jsp?x=0&Ntt=categorynumber77956 &Nty=1&showImages=true&N=4&y=0&Ntk=gensearch http://www.luxeonstar.com/item.php?id=391&link_str=208&partno=LXHL-BW03 http://electronics.howstuffworks.com/led.htm http://www.bulbs.com/products/product.asp?main=search


				
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