lighting technologies, retrofits and redesign …2 ©2007 rensselaer polytechnic institute - all...

Daniel Frering, LCLighting Research CenterRensselaer Polytechnic Institute

Lighting Technologies, Retrofits and Redesign

Strategies for Colleges and Universities

2

©2007 Rensselaer Polytechnic Institute - All Rights Reserved

NVLAP-accredited testing laboratory

30,000 ft² of research space near campus,

Rensselaer Polytechnic

Institute

Research andeducation = $4-6 million/year

Lighting Research Center

3


Introduction

• Lighting Technology Update– Energy-efficient lamps, luminaires, and controls– New or improved lighting technologies

• Energy-Efficient Lighting Retrofit and Redesign Ideas– Simple to more complex lighting retrofits or redesigns

• Case Studies– Examples of Energy-efficient lighting in educational

settings

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Linear Fluorescent

• Nomenclature

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Linear Fluorescent

• Color Designations• Select lamps with CRI 70+• Neutral CCT 3500 – 4100 K

6


Are Super T-8s super?

• Another name: High Performance T-8s• There are no standards that describe what a

“super” T-8 is• Each manufacturer defines the product differently

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Standard vs. High Performance T8

CEE* StandardHP T8 T8

• Mean system efficacy (MLPW) > 90 85-92• Color rendering index > 81 75-82• Min. initial lamp lumens > 3100 2800-2900• Lamp life (hrs) > 24,000 20,000• Lumen maintenance > 94% 90%-92%

* Consortium for Energy Efficiency, High Performance T8 Specific* Consortium for Energy Efficiency, High Performance T8 Specificationsations

http://www.cee1.org/com/comhttp://www.cee1.org/com/com--lt/comlt/com--ltlt--specs.pdfspecs.pdf

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NLPIP Lighting Answers - T8 Fluorescent Lamps

• Developments in 4 ft. 32 W T8 lamps• Provides overview of performance claims for initial light output,

rated life, lumen maintenance, and color• Generalization

– RE 70 = good– RE 80 = better– RE 80 LL HLO = marginally better: more $, more power, even

more light • Discusses uncertainties for specifiers associated with performance

attributes and with power requirements

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1

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2500 3000 3500 4000 4500 5000 5500 6000 6500 7000

Correlated color temperature (K)

Lam

p ef

ficac

y (lu

men

s pe

r wat

t)

RE90

RE80

RE70

*T8 lamps with efficacy greater than 80 lumens per watt

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RE80 RE80 HLO

LL

RE80 RE80 HLO

LL

RE80 RE80 HLO

LL

RE80 RE80 HLO

LL

RE80 RE80 HLO

LL

RE80 RE80 HLO

LL

3500 K 4100 K 3500 K 4100 K 3500 K 4100 K

Manufacturer A Manufacturer B Manufacturer C

Manufacturer and correlated color temperature

Lam

p ef

ficac

y (lu

men

s pe

r wat

t)

HLO - high light outputLL - long life

80

82

84

86

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92

94

96

98

100

CalculatedMeasured

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Where do I use Super T8s?

• Retrofit– One-for-one replacement of existing lamps

• Increases work surface illuminance– Replace lamp and ballast with Super T8 and low ballast

factor ballast• Maintain work surface illuminance and reduce energy

requirements by 14%– Redesign lighting system, reduce number of fixtures

• Maintain work surface illuminance and reduce energy requirements by 16%

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Where do I use Super T8s?

• New construction/remodeling– Design lighting system with Super T8

• Use less fixtures and less energy, assuming necessary fixture spacing can be achieved (lower first cost and operating cost)

– Design lighting system with Super T8 and low ballast factor ballast• Use same number of light fixtures; energy needs are

reduced by 14% (lower operating cost)

11


Reduced Wattage T-8 Options

Description Watts CCT K CRI Initial Lumens

Mean Lumens

Rated Life*

Standard T8 - 800 series Lamps 323000 3500 4100

86 2,950 2,800 20,000

Super T8 Lamps 323000 3500 4100

86 3,100 2,950 30,000

253000 3500 4100

85 2,400 2,28025,000 (12-hr. Start)

303000 3500 4100

86 2,900 2,750 20,000

283000 3500 4100

82 2,725 2,560 18,000

Energy Saving Lamps

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T5 vs. T8

• Which is more efficient?

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What is a T5?

• The “T” represents lamp shape–tubular.

• The number following represents lamp diameter in eighths of an inch. A T5 has a diameter of 5/8”.

• A T5 has a miniature bi-pin base while T8 and T12 lamps use medium bi-pin bases.

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T5 lumen maintenance vs. T8?

• Both T5 and T5HO lamps keep a better lumen maintenance level than T12 and most T8 lamps.

• They are claimed to retain 95% of light output at 8,000 burning hours (40% of rated average life).

• An improved phosphor coating reduces mercury absorption, leading to a higher lumen maintenance value.

(Online catalog of Philips Lighting)

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83900.905981880.88598592322,7142,950F32T8

85751.0011785751.001179381545,0004,400F54T5HO

94841.006283750.9063104 93282,9002,610F28T5

35°Clm/W

25°Clm/WBFInput

(W)35°Clm/W

25°Clm/W

BFInput(W)35°C25°C(W)35°C25°C

Manufacturer BManufacturer AEfficacy (lm/W)WattInitial lumen

(lm)

Lamp-ballast system efficacyLamp efficacy

Lamp type

T5 vs. T8

• Catalog data

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Do T5 lamps provide more light than standard T8 lamps?

• Ambient temperature significantly affects light output

• T5s rated @35°C

• Ballast loss is another factor – The maximum system efficacy at the optimal

temperature for each lamp-ballast system (T5 and T8) appears to be nearly identical on average

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Optical Efficiency: 1-lamp T5HO vs. 2-lamp T8

(a) 1-T5HO (b) 2-T8

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T5 Lamps: Conclusions

• Where should T5s be used?

Lower ceiling height

Smaller # of luminaires

Similar system efficacyLower running cost

Small<=Project=>LargeLower initial cost

Higher uniformity

Higher-end design

T8T5T5HORequirements

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Compact Fluorescent (CFL)

• Types– Pin-base for dedicated fixtures– Screw-base self-ballasted

• Modular• Integral

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Compact Fluorescent Lamps (CFLs)

• Screw-base– Swirl / “twist” / “dairy queen”– Circline, 2C (double circline), 2D– Covered (“bullet”, “globe”, “A-line”)– Reflector

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Color• CRI

– generally high – Typical CRI is 82

• CCT– Range (similar to linear T8 and T5)– 2700K, 3000K, 3500K, 4100K, 5000K

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• Life (average rated)– Life rated at 3 hours per start

•Frequent switching will reduce life– Lower wattage typically 10,000 hours– Higher lumen output twin tube up to

14,000 hours

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Ballasts for Fluorescent Lamps

Types• Magnetic

– Low frequency (60 Hz) operation– May produce audible hum– May produce noticeable lamp flicker– Inefficient lamp operation

• Electronic– High frequency (20 to 60 kHz) operation– Quiet – No noticeable lamp flicker– More efficient lamp operation

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Ballasts for Fluorescent Lamps

Electronic Ballast Types• Instant start

– Most efficient – May sacrifice lamp life if frequently switched– Cannot be dimmed

• Rapid start and Programmed start– Generally consumes an additional 2 watts– More gentle starting for frequent switching– Can be dimmed (if a dimming ballast is

selected)

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Ballast Factor

• Measures the ability of the ballast to produce light using the lamps it is intended to operate

• Must be considered when determining lighting system efficacy

• A lower ballast factor will reduce light output but will typically use less energy

BF = Lumens on Commercial BallastLumens on Reference Ballast

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Pulse Start Metal Halide

• Range of wattage - 50 to 450 W• Efficacy of 60-100 lm/W• Color Rendering Index 65 – 75 or better• Formats available ED17, 28 & 37

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Probe-start vs. Pulse-start

• Pulse-start – Faster warm-up and restrike– Improved efficacy– Longer lamp life

(up to 50%)– Improved lumen

maintenance (33%)– Improved color

stability over life

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HID vs. Fluorescent for High Bay Applications• Which works better?

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Why use fluorescent lighting?• Uses 10%-20% less energy• Can be dimmed, switched• Can be controlled by motion

sensor• Linear source, good for lighting

vertical surfaces• Longer life (24,000 hours)• Better/more consistent color• If using fluorescent lighting in high

bay applications, ensure fixture optics are suited for this purpose

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Why use metal halide?

• Fewer fixtures to install (lower initial cost)

• Fewer lamps to stock and change• Bi-level operation• Newer metal halide lamps provide

– Better color rendering than older technology

– Higher maintained lumens per watt (pulse start) than older technology

– Improved efficacy with electronic ballasts

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Automatic Shut-off Lighting Controls

• Time clocks• Occupancy sensors• Panel relays• Centralized controls

• These work,but implementation depends on wiring, installation, commissioning, etc.

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Time Clocks

• Turns lighting circuits on/off on pre-set schedule

• Electronic – allow up to 32 building zones, great scheduling flexibility

• Caution – more programming options may be too complex

• Manual override important in offices, etc.

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Time Clocks

• Use to control spaces with predicable occupancy (offices, classrooms, libraries, hallways, exteriors, etc.)

• Installed on lighting panel or building control system; can be retrofitted

• Proper commissioning/ programming important

• ASHRAE/IESNA 90.1 – mandated for buildings over 5,000 sq.ft.

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Motion/Occupancy SensorTechnology Issues

• Three technology types– Infrared– Ultrasonic – Dual technology

• All are mature technologies• Excellent payback potential• Work well with proper

selection and positioning

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Passive Infrared (PIR)

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Passive Infrared (PIR)

What are PIRs best at detecting?• Movements in a direct line of sight from the sensor—

PIRs cannot look around corners • Movements across the field of view (across the

segments) rather than movements toward or away from the sensor

What can cause “false triggering”?• People walking by in adjacent spaces that are visible to

the sensor (e.g., through a doorway)• Surfaces with sunlight falling on them (e.g., desks near

south-facing windows)• HVAC outlets or other machinery that heat up nearby

objects

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Ultrasonic

Ultrasonic waves emitted into the room at a constant pitch

Ultrasonic waves reflecting from a moving object back toward sensor

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Ultrasonic Occupancy Sensor

What are ultrasonic sensors best at detecting?• Movement in any part of the space, even around

corners or behind obstructions such as washroom partitions

• Movement toward the sensor, rather than movement across the space

What can cause “false triggering”?• People walking by in adjacent spaces that are

within the sensor’s range• Any object blown around by the wind or by the

ventilation system, such as plant foliage or mobiles.

• High velocity air currents from HVAC systems

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Duel Technology or Hybrid

• Combines both technologies in one product

• Most expensive options• Very sensitive to motion while

preventing “false triggering”(critical areas such as machine operation, health care)

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Motion Sensor Economics

How much energy do occupancy sensors save?

Owned SharedSpace Space

Sporadic Use: 25% 40%Scheduled Use: 30%

• However, savings for a specific space may vary from these mean numbers.

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Photosensor Technology Issues

• Analog design of control algorithm makes it difficult to accurately adjust the photosensor during commissioning

• Lack of manual controls to adjust photosensor to individual preferences

• Minimal integration with other lighting controls, i.e.,occupancy sensors

• Can save 20 to 40 % of lighting energy if installed and commissioned properly

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Daylight Dimming

• Development and evaluation of newly improved photosensor– Wireless, remote sensor– Self-commissioning– Occupant preference

adjustment independent of commissioning

– Switching + dimming– Compact size – Efficient (~1.2 watts @ 120V)– Microprocessor based Commissioning time < 3

minutes in most cases!

Sponsor: Connecticut Light and Power

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0

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Feb-02 Mar-02 Apr-02 May-02 Jun-02 Jul-02 Aug-02 Sep-02Time

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Daylight Dimming

“We have eliminated commissioning hardships by using microprocessor-based logic functions and control algorithms..”

Andrew Bierman

Sponsor: Connecticut Light and Power

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Fluorescent Lamps Weren’t Designed for Dimming

• What compatibility issues exist to allow fluorescent lamps and dimming ballasts to work together without degradation to lamp life?

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Daylighting Controls: Making Them Work

• Daylighting controls require:– Proper selection of the

correct controller for the design situation

– Proper location of the controls

– Proper adjustment to ensure correct operation

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DaySwitch

• Automatic on/off• Designed to retrofit• Low cost

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Dayswitch Energy Savings Potential

Energy savings comparision of systems in open office plans for different cities

15%12%

14%

17%

13%

24%

19%22%

28%

20%

37%35%

37%39%

34%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

Albany NY Sacramento CA Portland OR Charlotte NC Phoenix AZ

Ener

gy s

avin

gs o

ver b

ase

case

Dayswitch DaySwitch and AutoBlinds Perfect dimming

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Manual Dimming Controls

• Provide flexibility and control– Comfortable & functional visual environment– visual tasks have the right light level when and where required– dimming (or switching) is available for immediate darkening or

high illumination– different needs of adjacent areas are accommodated

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– Typically wall mounted (easily accessible location)– Office workers & teachers rate dimming highly as a lighting benefit– Allows more flexibility for presentations, computers, etc. – Many occupants will keep their lights dimmed for significant periods

of time – Studies have shown that providing dimming control can save 10 to

15 % of lighting energy

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• Dimming fluorescent lamps will require a dimming ballast and compatible dimming control

• HID Lamps have limited dimming capabilities• Consider switching strategies

– Tandem wiring of fixtures– No dimming ballast required– Still allows flexibility in adjusting lighting – High / low levels– Works well with HID systems

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Lighting and Load Management

• Lighting is an ideal electric end use for load management– Available in virtually every building– Easy to control– Easy to measure the results– The load reduced is repeatable– Can reduce the amount of lighting rather than

turn it off, thereby preserving productivity• Occupants find 30% to 50% reduction

acceptable

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Panel-level Power Reducers

• Installed on entire lighting circuits• Can be used on fluorescent or

HID lighting• Reduces voltage to the ballasts• Reduce power by 25%• Cannot be used with self

regulating ballasts

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Load Shed Ballast System

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Efficacy & projected efficacy of LEDs

White LED (R&D)

Incandescent

Projected for SSL

Fluorescent

0

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100

150

200

250

1990 2000 2010 2020

Year

Effic

acy

(lm/W

)

White LED (commercial)

OIDA Technology Roadmap update 2002

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LED products: Luminaires

• Hundreds of products at every trade show– Colored applications – RGB – General illumination – white

• Adjustable color temperature

©Color Kinetics 3000 K 3500 K 6500 K

©io Lighting ©Lumileds

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Summary – LEDs

• LEDs are evolving very rapidly• Currently there are many niche applications for

LEDs– Consumer electronics– Automotive/transportation– Full color dynamic displays– Architectural lighting (colored and white)

• Exploiting the unique attributes of LEDs will lead to successful applications

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Full Spectrum Lighting

• No standard definition of full spectrum lighting

• Manufacturer Claims include– Better visibility, improved color rendering, better

health, slows aging of the retina, reducing chances of skin cancer, improved mood, improved scholastic performance, greater productivity

• A survey conducted by the LRC showed that most people believe these claims

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Full Spectrum Lighting

• There is no evidence to support most claims associated with full spectrum lighting

• Light Sources promoted as full spectrum can cost over 10 times as much as nearly identical products that do not bear the full spectrum claim

• Full spectrum light sources generally have efficacies 30% to 40% lower then conventional fluorescent lamps.

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Lamp Spectral Power Distribution (SPD) & Task Performance

• Belief – Amount of light can be reduced, and task performance maintained, if lamps with high CCT’s>5000K are used

• Basis – Lamps with higher CCTs cause smaller pupil size, which allows increased focus

• Use of high CCT lamps is being suggested as an energy saving measure

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Lamp SPD & Task Performance

• Research results – Lamp spectrum does not affect task performance at

typical light levels – Lamps with higher CCTs will be perceived as brighter at

the same illuminance – Many people feel that high CCT lamps make a space

feel “cold,” “clinical,” “uninviting”

• Conclusion– There is no support for the belief that lamps with high

CCT will improve task performance

Energy-Efficient Lighting Retrofits

Steps to take to reduce lighting energy use

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Lighting and Energy Savings

• Lighting represents between 30 and 40 % of a typical college’s or university’s energy costs.

• An energy-efficient lighting system can typically save thousands of dollars per year.

• Energy-efficient lighting strategies present easy opportunities without major expense.

• Energy saving strategies for lighting range from simple to complex.

• Choose the most efficient lighting equipment.

63


Efficacy

• The amount of light emitted by the total lamp power input.

• It is expressed in lumens per watt (lm/W)

Lamp efficacy: total luminous flux (lm)total lamp power input (W)

System efficacy:rated lamp lumens x BF total input watts (lamp + ballast)

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Efficiency = Lumens emitted by a luminaireLumens emitted by the lamp(s)

Luminaire Efficiency

• The ratio of light (lumens) emitted by a luminaire to that emitted by the lamp or lamps used therein.

• Percentage of initial lamp lumens that are ultimately emitted by the luminaire

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Simple – Turn Lights Off

• Turning lights off in unoccupied rooms saves between 8 and 20% of lighting energy.

• Entire college needs to participate– Energy efficiency needs to be a

university goal– Organize student “light patrols.”

• Don’t turn lights on in the morning until people arrive.

• At night, most of the lighting should be turned off.

66


Simple – Clean Lighting Fixtures

• Dirt and dust on lighting fixtures reducing the efficiency by 15% a year.

• Periodically clean lamps and fixtures with a soft, dry cloth.

• Replace diffusers (lenses) when they begin to yellow.

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Simple retrofits

• Exit signs – replace with ENERGY STAR, saves 80 to 95% of energy

• Replace T-12 lamps & ballasts with T-8 lamps & electronic ballasts.

• Replace incandescent lamps with CFLs where appropriate

• Delamp T-8 fixtures if areas are over-lighted (cautions)

68


Install Occupancy Sensors

• Use in rooms that are intermittently occupied:– Classrooms– Faculty lounge– Staff room– Storage areas– Restrooms

• Less than 3 year payback though energy savings• Incentive $ available in some States to help pay

for purchase and installation

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Time controls

• Use time clocks to automatically turn lights off at a preset time in areas that have predictable occupancy hours– Offices– Libraries– Auditoriums– Some classrooms– Exteriors

70


Photosensors

• Proper commissioning is very important.

• Use them to switch lights off in areas with a lot of daylight.

• Use then to dim lights in areas with more variable daylighting conditions.

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Renovation – Lighting Redesign

• Lighting system replacement should be considered if the existing lighting system is:– More than 15 years old– Not operating properly– System components are deteriorating– Inefficient and/or ineffective (Watts per sq. ft.)

• Redesign should also be considered if: – The space is over lighted– Other renovations are being undertaken– The lighting is not providing the necessary conditions

Case Study: Integrated Classroom Lighting System (ICLS)

Funded by the California Energy Commission

System to be tested in New York State in 2007

Case Study presentation courtesy of FineLite.

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Study Methodology• Evaluated wide-range of products that would be

available by 2005

• Designed and installed a preliminary ICLS system

• Installed an improved ICLS in 18 classrooms in 6 schools

• Monitored actual usage and energy consumption for a year

• Conducted teacher preference surveys

• Installed an enhanced ICLS at SCE training center

• Developed a report that documents the study

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ICLS Findings:• Use high-performance, pendant indirect luminaires• Provide an Audio / Visual (A/V) mode under teacher control• Locate easy-to-use controls at the front of the classroom• Use dual technology occupancy sensors with teacher-

controlled delay• Tie the parts together with low-voltage, plug-and-play

cables• Ensure one manufacturer assumes system responsibility• Offer options including:

– Photo-sensors for daylight control– A dedicated whiteboard luminaire– Dimming for A/V presentations

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How the system works: General Mode: light faces, light vertical wall surfaces, cut

glare

• Walls and ceilings are well lit

• But, veiling reflections can wash out the screen.

• One simple switch removes all veiling reflections.

• The lighting changes from “GENERAL” to “A/V MODE.”

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How the system works:A/V operation reduces veiling reflections

• The screen now looks sharp

• Downlight delivers the right light on desks

• Dimming can be added as an option.

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How the system works: General Mode: Two outboard lamps are switch on

• The ICLS luminaire is wired so the outboard lamps are separate from the center lamp.

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How the system works:A/V operation reduces veiling reflections

• Reflector over center lamp is 96% reflective

• 100% of light directed down to the desks

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ICLS typical layout

• Luminaires– 2-rows– 14-foot centers– 24-inch suspension– Perpendicular to

whiteboard– For over 50 foot

candles at less than one watt / square foot, use 3100 lumen T8 lamps and 1.2 BF electronic ballasts

80


ICLS w/ whiteboard Layout• Pendant Luminaires

– 2-rows pendant luminaires

– 14’ centers– 24” suspension– Perpendicular to

whiteboard• Whiteboard Luminaire

– 12’ Length– 1T8 cross section– 30” Setback from wall– 12” Suspension

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ICLS typical layout

• Controls and sensors– TCC by whiteboard– Occupancy sensor

in center of the room

– Row switches by door(s)

– Control Pack above door

Teacher Control Center

Control Pack Occupancy Sensor

82


ICLS typical layout

• Interconnections– Low voltage– Plug-and-play

between TCC, sensors, and Control Pack

– Row switches (high voltage)

Teacher Control Center

Dual Occupancy Sensors

Row Control

83


ICLS is energy efficient

84


ICLS is cost effective

NA0.80$955$1,100($1.15 / sq ft)

3rd Row(3 Rows / room)

2-3 years0.20$355$500($0.52 / sq ft)

A/V Dimming (2 Rows, 1-Lamp)

3-6 Months0.47$30$175($0.18 / sq ft)

Daylight Switching(each row)

Immediate!0.80- $145$2,600($2.71 / sq ft)

ICLS System(A/V + Occupancy)

None1.35$0$2,745 ($2.86 / sq ft)

15 Parabolics

PaybackEnergy (w/sq.

ft.)DifferenceInstalled CostAlternative

85


Teachers prefer ICLS 9 to 1

86


Heritage Oak control classroom(1.75 watts / sq foot)

87


Heritage Oak ICLS system(0.8 watts / square foot)

88


Dudley Elementary School(1960’s vintage fixtures, 1.7 watts / sq ft)

89


Dudley Elementary School(Low Voltage Retrofit, 0.9 watts / sq ft)

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Lessons Learned - Classrooms

• Control daylight to minimize direct and reflected glare and reduce light levels for audio-visual programs or computer work

• Provide switches at the instructor’s desk in a video projector environment

• Illumination of white boards must be considered carefully

91


Case Study – Community College

Computer ClassroomsLocation of lighting and / or furniture location matters:• Visibility:

• light levels for video projection vs. taking notes• Comfort:

• Darker and shadows along walls in periphery classrooms • reflections on computer screens in front-facing classrooms

92


Case Study – Community College

Computer Classrooms• Classrooms with video

projector may require low light levels

• Low ambient levels increase visibility of projector images, BUT may interfere with student note taking

• Location of video projectors and below-ceiling luminaires must be carefully coordinated

93


Conclusions

• When evaluating existing lighting conditions you need to consider – efficiency (energy use),– Maintenance, and – Effectiveness (how well the lighting meet the needs of

the people who use the space).

• Illuminance (the amount of light) is not the only factor to consider in performing a lighting evaluation

94


Conclusions

• Lighting efficiency strategies can save a significant amount of energy is a typical school – between 20 and 60 % depending upon technologies

selected and existing conditions

• There are many strategies that can be considered– Choose the most efficient equipment (lamps, ballasts,

lighting fixtures, controls)– Turn lights off when not needed (manual or automatic)– Use daylighting where possible (be careful with

controls)– Consider a lighting redesign if needed and cost effective

95


Thank you!Additional Information

www.lrc.rpi.edu

Dan Frering, LCManager of Education

Lighting Research CenterRensselaer Polytechnic Institute

[email protected]

lighting technologies, retrofits and redesign …2 ©2007 rensselaer polytechnic institute - all...

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