Presentation to BSE Feb 2012_2

7/31/2019 Presentation to BSE Feb 2012_2

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R A AttalageDepartment of Mechanical Engineering

University of Moratuwa

2/10/2012 University of Moratuwa All Rights Reserved 1


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Outline

Insight

Lighting Terminology

Lighting Technologies & Efficiency

Standards & Labels



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Insight......Lighting

World around us is perceived throughLight, either natural or artificial.

Light plays a critical role in how we

perceive space. Light provides Life to the occupancy

zone of our interest.

Occupants performance, mood, safety,security and decisions.

Lighting also has strong health, socialand emotional significance.

2/10/2012 University of Moratuwa All Rights Reserved Slide 3


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Synergetic Requirements



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Exterior/Architectural Street Lighting


Aspects......


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Interior



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Motivation About 25% of electricity in Sri Lanka is used

for lighting.

The peak demand occurs mostly due tolighting.



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About Light

What is Light?From Electromagnetic Theory:

Radiant energy in the form of electromagnetic wavescapable of exciting the retina and producing the Visual

Sensation (380-780 nm wave length)

Radiant energy that excites the human eye is produced by

Incandescence (Incandescent body)

Fluorescence (Gas discharge) Solid-state device (Semi-conductor)



About Light

Visible range in the Electromagnetic spectrum


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Spectral Power Distribution

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Spectral Power Distribution (SPD)

A pictorial representation of the radiant poweremitted by a light source as a function of the

wave length of the visible range

Source: Indoor & Outdoor Lighting 2008/2009 - OSRAM




Luminous Flux (Light output)

Time rate flow of Light emitted by a source in ALLdirections

Measured in Lumens (lm)

A lamp has one Lumen output rating

Lumen ratings are determined and published by

the manufacturers (using Integrating Sphere)Value may depend on temperature or position and

depreciates with time




Lumen Values

Initial Lumens (Rated Lumens) i.e. beforedepreciation occurs (due to deterioration of components)

Mean Lumens (Design Lumens) i.e. Lumens at 40%of the Lamp life

34 W T12 Cool White Fluorescent has initial lumens of2650 and mean lumens of 2280

(Source: OSRAM/SYLVANIA & Philips catalogue)

Therefore for realistic estimations, lightingpractitioners should use Mean Lumens in estimations


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Luminous Flux (Light output)

SPD of the source weighted by the SpectralSensitivity of Human eye



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Is Light Measurement at Nightthe Same as during the Day?

St arlight Moonlight Dim int er iors Off ice light ing Daylight

Scotopic Mesopic Photopic

Radiant Energy

Source: LRC of RPI, NY

2/10/2012 University of Moratuwa All Rights Reserved




Luminous Efficacy

Ratio of the total Luminous flux of a lamp to itstotal power input (i.e. lm/W)

Gives an indication of the energy added (as heat)into the space where the lamp is placed

An important parameters for comparison or

selection of lampsAt 555 nm there are 683 lumens/Watt ( at max

sensitivity point of human eye)



Source Efficacy (lm/W) including Ballast

Standard Incandescent 5-15

Tungsten Halogen 10-25

Halogen Infrared Reflecting 20-35

Fluorescent (linear & U-tube) 25-100

Compact Fluorescent Lamp 25-70

Mercury Vapour 25-50

Metal Halide 45-100

High Pressure Sodium 45-110

Low Pressure Sodium 80-150

Natural Light 105

LED 50-150*

Source: E Source Lighting Atlas



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Implications At nighttime (mesopic) light levels,

peripheral vision is not predicted byconventional light level measurements

Bluish-white light sources will be moreeffective at low light levels

Bluish-white light sources used at lowerlight levels can conserve energy withoutcompromising visual performance

Potential applications:

roadway and parking area lighting nighttime pedestrian lighting

security lightingSource: LRC of RPI, NY


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Austin Energy Results

Virtually no change in user safety or securityperception

Substantial energy savings 250 watt HPS to 100watt fluorescent

(two twin-tube lampsat 50 watts each)




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Comparison among light sources




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Correlated Colour Temperature (CCT) Absolute temp of a blackbody whose

chromaticity most nearly matches that of theLight source

Colour appearance of a lamp measured inKelvin

CCT of a lamp is a measure of a warmth orcoolness of its appearance

Below 3200 K - Warm (Yellowish white)

Between 3200 K & 4000 K (Neutral)

Above 4000 K Cool (bluish white)



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Correlated Colour Temperature (CCT)



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Colour Rendering Index (CRI)

Measure of the degree of the colour shift theobjects undergo when illuminated by light source

as compared with the color of those objects whenilluminated by a reference source



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CRI indicates how natural the colour of an object willappear

Incandescent is the reference source for lower CCT

sources Daylight is the reference source for higher CCT sources

Comparison of CRIs should be done for sources havingsimilar CCT

CRI of above 70 is required for many applications

Note: Colour of white human skin has been considered

as the yard stick in establishing CRIs


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Source CRI

Incandescent 100

Linear Fluorescent 75-85

CFL 82

Standard Metal Halide 65

Standard HP Sodium 22

Daylight 100

Source: Lighting Research Center, RPI, NY



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Intensity (Candlepower)

Light emitted by a source in a specific direction

Remains the same regardless of the distance

Value of the Intensity depends on the direction Uniform intensity source has same intensity in

ALL directions

Defined as Amount of light in a unit Solid angle

i.e. Lumens per Steradian also called Candela(Cd)



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Intensity (Candlepower) - Polar Curve

600 Cd

1000 Cd45 Cd


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Illuminance

Areal density of the luminous flux incident ata point on a surface

Calculated as amount of lumens per unitarea

Denoted in Lux (lm/m2) or footcandle (lm/ft2)

Horizontal illuminace, vertical illuminance etc

R2-Law



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Recommended Illuminance


Area or Activity LuxIndustrial Assembly/Inspection

simple

difficult (garment factory etc.)

exact (lapidary- cutting, shaping of jewellery)

300

1500

7500

Machine shops

rough machining

automatic machine, grinding, polishing

fine bench work

300

750

3000

Material handlingwrapping, packing, labelling

stock taking, classifying

loading, unloading

300

300

150


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Area or Activity LuxReading printed matter

6-point typeface

8 t0 10-point typeface

newsprint

telephone directory

750

300

300

750

Office space

minor clerical work

computer/typing

drawing/sketching

300 ~ 500

500 ~1000

1000 ~ 2000

Residential space

living room

reading room

kitchen/bedroom

150 ~ 300

300 ~ 500

150 (general), 300 (local)


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Age Lux10 ~ 20 years

40 years

above 60 years

200

300 ~ 500

1000 or above

Illumination required for reading printedmatter depends on the age of the readertoo.


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Luminance

Luminous flux at a point into a unit solidangle perpendicular to a unit surface around

that point of a light source Indicated in Cd/area, ex: Cd/m2

Luminance of surfaces immediately adjacentto the task should not exceed the luminance

of the task but should have at least 1/3 ofthe task



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Three Basic Quantities


It is about visualbrightness

It is about lightlevel

It is about totallight emitted

It is about light emitted ina given direction


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Luminaires (Light Fixture)

Complete lighting unit consisting of a lamp,starting device and the components

designated to distribute light and protect &power it

Luminaire Efficiency is defined as the ratio ofluminous flux emitted by the luminaire to that

emitted by the lamp alone


lampthebyemittedLumens

lumnairethebyemittedLumensEfficiency

____

____

=


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Lighting Technologies &Efficiency

What does world of lighting want?

Acceptable return on investment (ROI)

Easy installation, O & M

Proven & tested products Successful use technology is found

elsewhere

Dissemination & communication withdevelopers, designers & owners



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Types of Lamps

Three (3) major categories Incandescent lamps.

Fluorescent lamps.

High Intensity Discharge (HID)lamps.

An emerging fourth category

Light emitting diodes (LEDs).

White LED lamps.



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Lighting Technologies &Efficiency Standard Incandescent

Nomenclature (ex: 40 T 10)

Life (average rated)

750 2000 hrs, dimming extends life, switching noeffect, using at rated or higher voltages effects life

Distribution (both non directional or directional)

CRI 95+

CCT 2500-3000 K (warm white) Efficacy around 10-15 lm/W



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Halogen

Filament lamp with inert gas with trace of halogen

Nomenclature (ex: 60 A/HAL 10)

Life (average rated)

2000 hrs, dimming reduces life, switching no effect,using at rated or higher voltages extends life

Distribution (both non directional or directional)

CRI 95+, CCT 3000K (warm white)

Efficacy about 25 lm/W



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Linear Fluorescent

UV generated within the gas inside the lampconverted to light by a phosphor coating

Nomenclature (F 32 T 8 / RE 8 30) Life (7500-10000 hrs)

CRI (75-85)

CCT (3000-6500 K, cool white to daylight)

Efficacy (25-100 lm/W)

T12, T8 & T5 lamp types



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Type Rated Power(W)

Light Output(lm)

Efficacy (lm/W)

T5 35 3600 100

T8 32 2800 85

T12 40 2650 70


Li h i T h l i


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Compact Fluorescent

Nomenclature (same as linear with CF lamptype)

Life (7500-10000 hrs) Distribution (normally directional)

CRI (80-85)

CCT (2700 5000 K)

Efficacy (25-70 lm/W)


Li h i T h l i &


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Fluorescent Colour Temperatures

2/10/2012

University ofMoratuwaAll RightsReservedSlide 45

Commonlysold in SriLanka

2700K

3000K

3500K

4000K

5000K

6500K

CCT ( K)Standard Fluorescent

Colours

2400 incandescent light

3000 warm white

3500 white

4000 cool white

5000 daylight

6500 cool daylight

Li h i T h l i &


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Ballasts for Fluorescent

Device used for electric arc discharge lampsto control voltage, current & wave form

Operation of Fluorescent and HID lamps Ballasts for fluorescent formerly magnetic,

electromagnetic (operating 60 Hz) andcurrently electronic (20,000 -60,000 Hz)

Electronic ballasts convert power to lightmore efficiently



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Function of Ballast

2/10/2012

University ofMoratuwa

All RightsReservedSlide 47

The ballast supplies a higher voltage for striking. Immediately after striking, the voltage across the

electrodes becomes very low.

This occurs since an electron arc establishes a

conductive path between electrodes during start up. The lamp current during this period could increase

to destructive levels if not controlled using theballast.

Hence the ballast has two functions: To control current just after ignition (start up) and alsoduring normal operation,

To provide ignition voltage.

Li hti T h l i &


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Ballast Factor (BF)

Measure of ability of the ballast to provide lightoutput of a given lamp w.r.t. a Reference ballasts

Actual Lumens of Lamp= Rated Lumens of Lamp x BF

Ballast Efficiency Factor (BEF)

Ratio of the BF to input power to that ballast

Higher BEF indicates a more efficient ballastBEF = BF x 100/Input power (W)

Li hti T h l i &


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Lighting Technologies &Efficiency High Intensity Discharge (HID)

Produce light using an electric arc tube

Arc tube contains a starting gas depending on the type oflamp and also contains metals or Halides

Lamp types are Mercury Vapour, Metal Halide, High/lowPressure Sodium

Mercury Vapour lamps excite Mercury atoms

Metal Halide lamps excite several types of atoms

Sodium lamps excite Sodium atoms

HID lamps emit visible radiation and do not requirePhosphor coating

Starting device is needed

Superior efficacy, low CRI, longer life


Li hti T h l i &


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Li h i T h l i


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Source Rated Life (hours)

Incandescent 1000

Halogen 2000

Fluorescent 7500-10000Mercury Vapour 24000

Metal Halide 12000

HP Sodium 24000

LP Sodium 15000

LED 1000-100,000*



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Lighting Evaluation

Change in operating conditions


Li hti T h l i &


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Lighting Technologies &Efficiency LEDs

Solid state light source

Powerful enough and becoming cheaper toreplace conventional lamps, highly adaptable in

form LEDs need special packaging for protection,

light distribution & heat dissipation

White LEDs are the state of art

Heat dissipation has a huge impact on life Efficacies in 40-55* lm/W, life 100,000* hrs !

low UV and no Hg content


Li hti T h l i &


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Solid state light source

Powerful enough and becoming cheaper toreplace conventional lamps, highly adaptable in

form LEDs need special packaging for protection,

light distribution & heat dissipation

White LEDs are the state of art

Heat dissipation has a huge impact on life Efficacies in 40-55* lm/W, life 100,000* hrs !

low UV and no Hg content


Lighting Technologies &


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LEDs




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LEDs




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Lighting Technologies &Efficiency Luminaire (Light Fitting)

Types Reflective, refractive or combined

Distribution control the directional properties of the source

ex: direct, indirect

Use reflectors, lenses diffused or prismatic

Shielding

shield lamp, block unwanted light

Use louvers, baffles




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Luminaire (Light Fitting)




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Lighting Technologies &Efficiency Lighting Controls

Functions Switching off when not needed (energy money

save)

Adjust the quantity of light in response to theend use (energy save, change ambiance)

Types

Timer clocks (simple & cheap, manual or

programmed) Occupancy sensors (IR, PIR, Ultrasonic)

Daylight sensing




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Lighting Technologies &Efficiency Lighting Controls

Application Sensor sensitivity and coverage area are issues

Occupancy sensors have potential for Intermittent

use In general around 30% of lighting energy savings

possible

Emerging

Digital control, wireless control devices Lighting automation through Building Automation

Systems (BAS)

DDC (direct digital control)




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Lighting Controls



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Occupancy Sensors

Three different technologies Infrared (PIR)

Ultrasonic

Dual technology

A photocell for day light sensing is sometimesincorporated in to these products.

They are mature technologies.

Payback potential is great if employedstrategically.

For good utilisation, proper selection andmounting is important.



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PIR motion sensor PIR occupancy switch, wall mounted


Detection zone: 120Time lag range: 10 seconds to 40 minutes in 9 stepsPhotocell range: 100 to 1000 lux, and inactiveLoading: up to 6 amps (1500W) of any type of loadSize (mm): 86 x 86 x 22

Source: www.danlers.co.uk



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Lighting Technologies &Efficiency Daylight

Best source of Lighting

Almost highest level of efficacy (100 lm/W)

Reference for many CRI estimation Found to have favorable impact on Human

health

Use of Daylight

To be integrated to a maximum Consider at building design stage

Attention to glare issue, sky models




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Lighting Evaluation

Example:

Two fluorescent lamps each rated 2850 lm operate on a 2-lamp electronic

ballast. The ballast has a BF of 0.95 with total input power of 62 W.

Determine the Luminous Efficacy of the unit.

Luminous Efficacy = 2850 x 2 x 0.95 / 62 = 87.3 lm/W


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Lighting Evaluation

Example:

Determine the Illiuminance field 2.5 m below an Incandescent lamp

considering it as a point source of non-uniform intensity

0 20 40 60 80I (Cd) 420 450 380 200 70

E = I/H2

E = I Cos3/H

2

I Intensity at an angle H Vertical height from the source

E Illuminance at an angle

0 20 40 60 80

E (lux) 67.2 59.7 27.3 4.0 0.06


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Standards & Labels

Standards & labels Minimum Efficiency Performance Standard

(MEPS)

Labels pull the appliance performance in themarket over and above MEPS

Identified as an economically attractivemethod for energy efficiency

Advantage for product developers

Starting Energy Management Program Strategy ???



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Code of Practice

Energy Efficient Building in Sri Lanka 2008. Objectives.

Mandatory requirements.

Maximum allowable power for illumination.

Building exterior lighting power.

Selection of appropriate components.

Lighting controls.

Strategy for energy efficient lighting. Submission procedure.



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Objectives of EEBC

Use minimal electrical energy to providelighting to the quantity and quality ofstandards.

It is however necessary to evaluate theequipment, techniques and servicesavailable for both existing and proposedinstallations in order to meet these

requirements.


Examples of Economic Analysis


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Examples of Economic Analysis

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Simple Payback Period (SPP) Estimate the SPP for replacing 100 nos. of 75W incandescent lamps with

15 W CFL lamps if they operate 24 hours a day, seven days a week whenelectricity tariff is $ 0.10 /kWh.

Costs ($) Incandescent 1.0, CFL 15.0

Life (hours) Incandescent 1000, CFL 8000

Energy savings per lamp = (75-15) = 60 W

Energy savings per day = 60 x 100 x 24 = 144 kWh/day

Annual energy savings = 144 x 365 x 0.10 = $ 5250

SPP = $(15 x 100)/$ 5250 = 0.3 years

Source: Energy Efficient Building Systems, L Jayamaha, Mc Graw-Hill, 2006


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Presentation to BSE Feb 2012_2

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