Lighting with Artificial Light 12 pdf

Direction of light andmodelling Shapes and surfaces in the room need to be clearly visual performance and comfortably visual comfort identifiable.. This is rated by which indicates how n

Fördergemeinschaft Gutes Licht

Lighting quality

Electronic ballasts for

Effective and efficient Fine-tuned to human needs.

Lighting technology in the age of electronics.

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In addition, indoor place lighting standardDIN EN 12464 cites

work-• no flickering and

• harnessing of daylight

as other “main features”

Visual comfort, visualperformance, safetyUnlike old standards, DIN

EN 12464 does not focussolely on visual perfor-mance On the contrary,the first lighting objective

it sets out is

• visual comfort

This gives people at work

a sense of wellbeing andthus helps boost theirperformance

A second, equally tant objective is

formu-• safety

From a lighting viewpoint,safety (reliable identifica-tion) requirements at aworkplace are met wherethe stipulations for visual

New lighting quality

standards

Within the framework of

European harmonisation,

new standards are being

developed to replace

na-tional ones Against the

backdrop of the revision

and reformulation of

re-quirements that this entails,

professionals have been

debating a new extended

concept of quality

The extended concept

of lighting quality

The practice of defining

lighting quality on the basis

of certain quality features

has stood the test of time

So the traditional yardsticks

will continue to be applied:

• illuminance,

• luminance distribution

(distribution of

bright-ness),

• limitation of glare (direct

and reflected glare),

• direction of light and

per-12464 apply to the visualtask zone and its immedi-ate surroundings, so zonedlighting is permitted This is

an important step in dardisation towards user-oriented lighting which can

stan-be tailored to requirements

The extended concept ofquality also includes theneed for lighting systemsand luminaires which areflexible: every user should

be able to adjust workplacelighting to suit his or her in-dividual requirements

Lighting quality

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Daylight utilisation

Another new aspect is the

greater emphasis on

day-light utilisation Harnessing

daylight for interior lighting

is widely regarded as a

sensible energy-saving

idea

Where opinion is divided

is over the amount of

day-light that ought to be

har-nessed Those who believe

it should be the maximum

permitted by the state of

the art point to the impact

of daylight and daylight

dynamics on our

biologi-cal clock (circadian

rhythm)

Energy-efficient

generation of light

Finally, the quality of a

lighting system also

de-pends on its economic

efficiency Although there

should be “no compromise

on lighting quality features

just to reduce energy

con-sumption” (DIN EN 12464,

subclause 4.9), artificiallight should be generated

by the most energy-efficientmeans possible

Among the factors shapingthe economic efficiency of

a lighting system are theenergy savings achievedthrough the use of lamps/

lamp+ballast systems withhigh luminous efficacy rat-ings, luminaires with a highutilisation factor, lamps, bal-

lasts and luminaires with along rated service life, andsystem components ofinstallation/maintenance-friendly design

Quality and lightingelectronics

Finer tuning to ments, more customisation,flexible, even dynamic con-trol, utilisation of daylightand efficient generation oflight – all these featurespresent technological re-quirements which are metonly by lighting electronics

require-Today, we have “intelligent”

energy-efficient operating

and control devices at ourdisposal, permitting lightingmanagement and thusbetter quality of lighting –quality which enables light-ing to perform an ergo-nomic function at the work-place as well as beinggood for our health

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DIN 5035 and DIN EN 12464

The main lighting standard atpresent is DIN 5035 “Artificiallighting”, which is essentiallybased on visual performancestudy results and industrial re-search findings amassed over

a period of more than 50 years

This national standard sets outminimums without any differen-tiation; it always refers to entirerooms

The new European standard DIN

EN 12464 “Guideline values forindoor and outdoor workplaces”,however, focuses on visual taskzones and their immediate sur-roundings It permits lightingmore finely tuned to require-ments

In March 2003, some of the tents of DIN 5035 Parts 1, 2, 3 and

con-4 were superseded by DIN EN

12464 “Light and lighting” Part 1

“Lighting of indoor workplaces”

Agreeable lighting climate and lighting tailored to re- quirements for a sense of wellbeing

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Illuminance has a major

bearing on the speed,

reliability and ease with

which we perceive and

perform a visual task So

together with luminance

distribution, it is important

for visual performance

Illuminance (symbol: E) is

measured in lux (lx) and

indicates the amount of

lu-minous flux (see page 6)

from a light source falling

on a given surface: 1 lx

illuminance is where an

area of 1 square metre is

uniformly illuminated by

1 lumen of luminous flux

Given the same level of minance, a white room ap-pears brighter than a darkone (see also “reflectance”,page 6)

illu-Measurements are taken onhorizontal and vertical sur-faces The yardstick usedfor defining how well verti-cal surfaces and objects in

a room – especially faces –are identified is cylindricalilluminance (see Fig 13)

Uniform distribution ofbrightness makes a visualtask easier to perform Uni-formity of illuminance takes

a surface as its referenceand is expressed as theratio of the lowest to themean illuminance regis-tered

Minimum mean illuminancevalues are stipulated instandards, e.g 500 lx foroffice work, 300 lx for gen-eral machine work and

500 lx for fine machine

work in metalworkingshops Illuminance values

in the immediate ings can be approximately

surround-a third lower; these vsurround-alues,too, are stipulated in thestandards

Illuminance levels can behigher than standard val-ues, of course, becausehuman beings are daylightcreatures: 100,000 lx insummer sunlight and20,000 lx on an overcast

day are what nature vides to meet our require-ments

pro-Luminance distributionLuminance distribution inthe visual field (distribution

of brightness) impacts onvisual performance and vi-sual comfort Luminance(symbol: L) is the bright-ness of an illuminated orluminous surface as per-ceived by the human eyeand is measured in cande-

a surface is defined by itsreflectance and the illumi-nance registered on it.Luminance distribution inthe visual field has a cru-cial bearing on visual per-formance because it de-

fines the state of adaptation

of the eye The higher theluminance, the better thevisual acuity, contrast sen-sitivity and performance ofocular functions (contrac-tion/dilation of pupils, eyemovement, etc.)

Visual comfort is impaired

• where luminance is toolow and differences inluminance are too slight;this creates a disagree-able lighting atmosphereproviding little stimula-tion;

Conventional quality features

100 300 500 700 900E (lx)

2,5 2,0 1,5 1,0 0,5

3,0 S

2,5 2,0 1,5 1,0 0,5

Fig 13 Cylindrical illuminance is the

mean vertical illuminance (E v ) on the

surface of a cylinder.

Fig 12 Illuminance (E) is measured on

horizontal (E h ) and vertical (E v ) surfaces.

Fig 15 Impact of illuminance

E on relative visual performance

P for simple (top curve) and

difficult (bottom) visual tasks

Fig 16 Impact of illuminance

E on visual acuity S of a person with normal eyesight

Fig 17 Visual acuity S as a function of age (average values)

Fig 18 to 21: Reflected glare

on screen (18) or glossy surfaces (20) impairs visual comfort and impedes visual performance.

Fig 14 The brightness of a luminous

or illuminated surface as perceived

by the human eye is known as luminance

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20

• where differences in

lu-minance are too marked;

this gives rise to fatigue

because of the constant

need for adaptation;

• where luminance is too

high; this can cause

minimum values for glare shielding are set out

anti-in standards Reflectedglare can be prevented by

careful positioning of lightsources, the use of mattsurfaces in the room andoptical control elementswhich limit the luminance

of luminaires

Where psychological glare

is avoided, there is

normal-ly no significant risk ofphysiological glare

Glare limitationGlare can be caused di-rectly by luminaires orother surfaces – even win-dows – which are exces-sively bright (direct glare)

or it can be caused rectly by reflections onshiny surfaces (reflectedglare) Both direct and re-flected glare are a source

indi-of visual discomfort chological glare) and im-

of the pupil The adaptiveprocess – and hence thetime it takes – depend

on the levels of nance before and afterany change in brightness.Adaptation from dark tolight takes only seconds;the process in the otherdirection takes minutes The state of adaptationaffects visual perfor-mance at any moment:the more light available,the faster efficient visualperformance can be re-stored Visual impairmentoccurs where the eyecannot adapt to differ-ences in brightness fastenough

lumi-Lamp

No lamp, no light: theterm “lamp” refers to anengineered artificial lightsource – incandescentlamp, fluorescent lamp,etc

The term “luminaire”refers to the entire elec-tric light fitting, includingall the components need-

ed to mount and operatethe lamp Luminaires pro-tect lamps, distribute theirlight and prevent themcausing glare

Fig 23: Direct glare is assessed by the UGR method; it takes account of all luminaires which could cause a sensation of glare

as well as the brightness of ceiling and walls

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Direction of light and

modelling

Shapes and surfaces in the

room need to be clearly

(visual performance) and

comfortably (visual comfort)

identifiable This calls for

balanced, soft-edged

shad-owing Shadow formation is

affected by the direction of

light, which is itself defined

by the distribution and

arrangement of luminaires

in the room

Highly directional light

gives rise to deep

hard-edged shadows Where no

shadows occur, however –

which happens when

light-ing is very diffuse – the

ef-fect is equally unpleasant

According to DIN EN

12464, the correct degree

of modelling is achievedwhere a balance is struckbetween directional anddiffuse lighting

For demanding visualtasks, e.g reading or work-ing with small parts, visualperformance is consider-ably improved by direction-

al lighting This can beused as supplementarylighting as long as theshadows created do notinterfere with performance

of the visual task

Light colour Light colour describes thecolour appearance of the

al colours appear under alamp’s light The colourrendering properties oflamps have implicationsfor visual performance andvisual comfort

The colour rendering index

is based on frequently

100 is the best rating; thelower the index value thepoorer the colour render-ing properties In interiors,

a colour rendering index of

regard-ed as a minimum

light which is radiated by

a lamp Light colours arebased on colour tempera-ture expressed in degreesKelvin (K):

warm white (ww)

< 3,300 K neutral white (nw) 3,300 K to 5,300 Kdaylight white (dw)

> 5,300 K

The light generated bylamps of the same lightcolour can have differentcolour rendering properties(see Fig 24)

Light colours affect the mosphere of a room andthus impact on visual com-fort: warm white light is felt

at-to be homely and cosy,neutral white light strikes

a more businesslike note

Daylight white light is onlysuitable for interiors whereilluminance exceeds 1,000lx; below that, it creates awan, monotonous atmo-sphere

Colour renderingThe colour rendering prop-erty of a lamp indicates theeffect its light has on theappearance of colouredobjects This is rated by

which indicates how

natur-Conventional quality features

8 9 10 11 12 13 13 15

16 17

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19 20

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1 De luxe fluorescent lamps, daylight 7 Three-band fluorescent lamps, daylight

2 Metal halide lamps 8 Metal halide lamps

3 De luxe fluorescent lamps, white 9 Three-band fluorescent lamps, white

4 De luxe fluorescent lamps, warm white 10 Compact fluorescent lamps, white

5 Tungsten-halogen lamps 11 Metal halide lamps

6 Incandescent lamps 12 Three-band fluorescent lamps, warm white

dw daylight white

nw neutral white

ww warm white

Closest colour temperature T CP

A lamp’s light is the same colour as a black body heated to that temperature.

Colour rendering index Ra

13 Compact fluorescent lamps, warm white 19 High-pressure sodium vapour lamps (Ra≥ 60)

14 High-pressure sodium vapour lamps (Ra≥ 80) 20 High-pressure mercury vapour lamps

15 Metal halide lamps 21 Standard fluorescent lamps, warm white

16 Fluorescent lamps, universal white 25 22 High-pressure sodium vapour lamps (R a ≥ 20)

17 Standard fluorescent lamps, white

18 Metal halide lamps

rate at which light isemitted by a lamp It de-scribes the visible lightradiating from a lightsource in all directionsand is measured in lu-mens (lm)

Reflectance indicates thepercentage of luminousflux reflected by a sur-face The reflectance oflight surfaces is high;that of dark surfaces islow This means that thedarker the room furnish-ings, the more light isneeded to create thesame brightness

Visual tasks are defined

by light/dark and colourcontrasts and the size ofdetails The more difficultthe visual task, the higherthe lighting level needs to

be

Visual performance isdetermined by the visualacuity of the eye and itssensitivity to differences

in brightness and ness

dark-Figs 25 to 30 Directional lighting (25, 26) gives rise to hard-edged shadows;

diffuse lighting (27, 28) results in a lack of shading Lighting which contains both

directional and diffuse elements (29, 30), however, makes for soft-edged shadows

which make shapes and surface structures clearly identifiable

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Light affects us physically,

spiritually and emotionally

The rhythm of day and

night and the dynamics of

daylight have a

fundamen-tal impact on our lives It is

not surprising, therefore,

that daylight indoors is

found agreeable and

heightens our sense of

wellbeing

The very least a building

needs to have is enough

windows to permit visual

contact with the world

out-side and thus at least

es-tablish a link with daylight

The advantages of daylight

can be harnessed much

more effectively, however,where it is actively directedinto interiors and distrib-uted there

Daylight systems (alsoknown as daylight control

systems) have been cifically developed for thispurpose They avoid thedisadvantages of uncon-trolled daylight incidence –uneven distribution of illu-minance, lack of light indeeper parts of the room– and provide anti-glareshielding on sunny daysand a means of regulatingroom temperature Anothermajor argument in favour

spe-of daylight systems is theamount of energy andmoney they save by har-nessing daylight as a full

or partial replacement forartificial lighting

Harnessing daylight tomaximum effectTaking a lead from VDIGuideline 6011 “Optimisa-tion of the Use of Daylightand Artificial Light”, pub-

lished by Verein DeutscherIngenieure (VDI) e.V., thedaylight utilization promo-tion group Fördergemein-schaft innovative Tages-lichtnutzung (FiTLicht) for-mulates basic requirementsfor the design of daylightsystems (German-languagewebsite: www.fitlicht.de):

• deflection of light to minate deeper parts ofthe room, enhancement

illu-of visual comfort, greateruniformity of luminancedistributed in the room,

• anti-glare shielding forlimiting luminance, espe-Harnessing daylight

Photo 39: Building façade with prismatic panels

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cially where VDU

work-places are present,

• transparency of the

sys-tem for maintaining a

link with outdoors (visual

contact), minimum

alter-ation of the colour of

inter-faces with building

auto-mation system or by

self-regulation

This list of requirements

shows that daylight

utiliza-tion cuts right across the

fields of lighting

engineer-ing, electrical and

electron-ic engineering, optelectron-ics,building service engineer-ing, building and façadecomponents, and architec-ture

Innovative daylightsystems

Optical control elements indaylight systems includespecular reflectors, prismsand holograms They changethe direction of diffuse day-light and/or direct incidentsunlight and deflect the na-tural light into deeper parts

of the room They also act

as anti-glare shielding

Innovative daylight systemsare available in variousdesigns as mobile or sta-tionary systems They aremounted on the inside or

outside of exterior walls,integrated into façades orroof surfaces Optical con-trol options range fromshutters and blinds to pris-matic systems and holo-graphic elements Addition-

al components – e.g flective ceilings – can beused to carry the daylightfurther into the room

re-One special form of light utilization involvesguiding daylight over rela-tively long distances: light-pipes or fibre-optic cablescan carry sunlight caught

day-by heliostats deep into abuilding

gy costs are reduced by morethan 70 percent

10 20 30 40 50 60 70 80 90 100

J F M A M J J A S O N D

Fig 43: Daylight varies, depending on graphical location, weather, time of year and day, surrounding buildings and anti-glare measures The average amount of daylight available in Central Europe, however, is al- ways relatively high The chart shows the potential daylight that can be harnessed for

geo-a stgeo-andgeo-ard office from Jgeo-anugeo-ary to December

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Many lighting applications

require standards of visual

comfort, visual ergonomy

and user orientation which

cannot be met by

conven-tional interior lighting What

is needed here is flexible

lighting capable of

deliver-ing the right light at the

right time

The lighting management

required to do this calls for

“intelligent” electronic

con-trol Also, the lighting needs

to operate in different

con-trol states, so individual

lu-minaires or groups of

lumi-naires need to be

sepa-rately addressable

Lighting managementsystems

Lighting management compasses all systemswhich go beyond mere

en-“on/off” control systemswhich control and regulatelighting by responding tovariance from setpointvalues

Lighting management toolswhich can be used at dif-ferent stages either alone

or in combination withothers include:

• pre-programmed lightingscenes for different activi-ties

• motion detectors primedfor instant activation,

Lighting management

to govern individual naires, individual rooms orgroups of rooms or theycan be wired into the build-ing management system(BMS)

lumi-For lighting tuned to quirements, lighting man-agement programmesneed to be accessible from

re-a remote control unit orcontrol panel and it must

be possible to make off overriding adjustments

one-to the lighting This – asexperience has shown –

is also vital for general ceptance: people otherwisefeel they are at the mercy

ac-of technology

Few components, little wiring and

simple programming – these are

the salient features of lighting

the standardized digital interface

for electronic ballasts (EBs)

oper-ating discharge lamps in lighting

control and regulation systems in

individual rooms or small building

units

As well as switching and dimming

individual components or

compo-nent groups, the digital interface is

also designed for more complex

programming, e.g for constant

light regulation DALI can also be

integrated into building

manage-ment systems (e.g BUS)

The working group AG DALI

(www.dali-ag.org), which operates

under the wing of the German

electrical and electronics

associa-tion Zentralverband

Elektrotechnik-und Elektronikindustrie e.V (ZVEI),

Frankfurt/Main, numbers among

its members leading European

and US manufacturers of

electron-ic ballasts and lighting control and

regulation systems

timed deactivation ordimming of lighting inresponse to movement(presence-dependentlighting control)

• daylight-dependent lation of lighting levels bydimming and/or partialdeactivation in response

regu-to signals from– light sensors on individ-ual workplace luminaires,– light sensors in the room, – exterior light sensors

The control and regulationcomponents of a lightingmanagement system areintegrated in luminairesand operator interfaces

They may be programmed

Lighting management makes for flexible lighting tailored to requirements.

“presentation” Otherexamples of need-orientedlighting control are lightingscenes such as “verybright”, “bright”, “dimmed”

or “working light”, tuated light”, etc

“accen-To permit tailored ment of lighting conditions,lighting scene parameters

adjust-need to be settable less of programming Withelectronic lighting controlsystems for lighting tailored

regard-to requirements, the maingain is convenience; ener-

gy savings are relativelyminor

Lighting scenes

With electronic lighting

control systems, a variety

of lighting scenes can be

simply programmed and

activated at the push of a

button to create optimal

visual conditions for

differ-ent situations

A classic example is

con-ference room lighting, with

programs for “general

light-ing”, “lecture” and

“presen-tation” scenes In an office,

programmed lighting

set-tings might be “desk work”,

“VDU work”, “meeting” and

Motion detectorsMotion detectors controllighting by responding tothe presence or absence ofmovement In many interi-ors where such systemscould usefully be installed,lighting stays on evenwhen no one is in theroom for lengthy periods,e.g during lunch

breaks Where ence is monitored

pres-by motion detectors,the lighting is deactivat-

ed after a pre-defined

“movement-free” periodand re-activated when thefirst person returning fromlunch enters the room

Another example: corridors

In hotels, in particular, thecommunication routes toguests’ rooms are rarelyused during the day Withmotion detectors, lightingcan be switched on when

it is required; there is noneed for maintained light-ing This solution is onlyrecommended, however,where there is enoughresidual brightness frommain corridor lighting oremergency lighting for ini-tial orientation

Motion detectors are alsoused in outdoor lighting

Along paths, at building trances or in parking lots,they provide additional lightwhen it is needed Integrat-

en-ed photoelectric lightingcontrollers ensure that themotion detectors work onlyduring the hours of dark-ness Where fluorescentand compact fluorescentlamps are used with mo-tion detectors, they need to

be operated by hot-startelectronic ballasts (EBs) forextra protection againstswitching voltages

Lighting control

Fig 46 to 48: Light scenes at the push of a button – (from top)

“desk”, “meeting”, “VDU work”

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Light sensors

Light sensors measure the

illuminance of artificial

lighting and/or daylight

(brightness sensors) They

form an important part of

lighting regulation systems

When pre-defined

thresh-old values are reached,

light sensors emit a signal

indicating the need for

dimmable electronic

bal-lasts (EBs), sometimes via

control modules These

may be supplemented by

motion detectors

Daylight-dependent

regulation

Lighting systems which

take account of daylight

entering through windows

or skylights or directed into

the room by special

light-deflecting systems (see

page 8) do not need to

deliver their full light output

at all times to achieve the

level of lighting required

The artificial lighting can be

dimmed and/or partially or

fully deactivated,

depend-ing on the level of incident

daylight

Daylight-dependent

regula-tion systems are normally

designed to ensure that the

sum of incident daylight

and regulated artificial light

maintain a constant level

of lighting throughout theroom (see Fig 50) Be-cause changes in thedaylight component areoffset by increases or de-creases in the amount ofartificial light, the illumi-nance required on thework surface thus re-mains more or less con-stant

When the light from doors is intense, the artifi-cial lighting is lowered;

out-when daylight levels arelow, e.g at dawn, dusk or

in dark winter months, thelevel of top-up lighting israised

Luminaires not near a dow need to generatemore light than luminairespositioned right beside awindow to make up for thelower daylight incidence

win-For visual tasks which quire more light, the set-point value should be re-settable from a handset

re-Daylight-dependent tion systems are realised

regula-on different scales: bilities range from simpleregulation of individualluminaires to centralisedregulation of luminairegroups, to full integration

possi-of all lighting systems intothe building managementsystem

Key components of theselighting regulation systemsare dimmable EBs and sig-nal amplifiers with lightsensors Each luminaire or

group of luminaires for aroom zone is assigned asensor which registers thecurrent horizontal illumi-nance and automaticallyadjusts the artificial lighting

to achieve the preset luxlevel This regulation sys-

tem can also be realisedwith exterior light sensorsinstalled at appropriate lo-cations

Lighting regulation

LLB operation

EB operation, non-regulated

EB operation (dimmable), daylight-dependent regulation

Fig 50: Daylight-dependent regulation for a constant sum of daylight and regulated artificial lighting

Fig 51: Comparison of the annual energy consumption of three rows of luminaires providing artificial lighting for a typical office (cf Fig 50)

Fig 52: In the morning, no light is

needed from the row of luminaires

near the window.

Fig 53: At midday, incident light is generally adequate.

day-Fig 54: In the evening and at night, the lighting needs to operate at full power.

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with 36 W fluorescentlamps operated by con-ventional ballasts (CBs) isreplaced by continuousrows of 90 luminaires, eachfitted with two 35 W 16 mm-diameter three-band fluo-rescent lamps operated bydimmable electronic bal-lasts (EBs)

The annual energy saving

is 76 percent Without light-dependent regulation,the new system wouldhave consumed only 15percent less energy thanthe old one

day-Comparison of the

regulat-ed (dimmable EB) systemwith a non-regulated, EB-operated system (see Fig.55) underlines the energy-efficient advantages of reg-ulation: the annual averageenergy consumption (light-ing required 6.00 – 18.00hrs) is 72 percent lowerthan that of the non-regu-lated lighting of the alter-native new system

dependent regulation tem almost always savesmore in energy than itcosts

sys-Office premisesCompared to a non-regu-lated lighting system oper-ated by conventional (CB)

or low-loss (LLB) ballasts,daylight-dependent regula-tion saves more than 70percent of energy costs

Even compared to a regulated system operated

non-by non-dimmable

electron-ic ballasts (EBs), the ings possible with a regu-lated lighting system oper-ated by dimmable EBs arestill very substantial Thedaylight-dependent systemconsumes 60 percent lessenergy Fig 51 shows howthe energy figures comparefor a typical office (2,300operating hours a year): –from left to right (cf Fig 50)– for the row of luminairesnear the windows, themiddle row and third rowdeep in the room

sav-Industrial premisesHarnessing daylight alsomakes a considerable dif-ference to the energy re-quired for lighting in facto-ries A refurbishment exam-ple (see table for compara-

in-dustrial bay with skylights,the old lighting system of

184 single-lamp luminaires

more agreeable than anyother Also, the energy sav-ings such systems permitshould not be underesti-mated Assuming adequatewindows or skylights, light-ing governed by a daylight-

Cost-cutting potential

of daylight utilisation

The decision to harness

more daylight is taken

mainly because of the

pos-itive way we respond to it:

we find natural lighting

* Without dimming, the connected load of the whole system is 7.02 kW Where

light-ing is dimmed, the connected load is based on the reduced output, e.g 6.32 kW

where lighting is dimmed to 90 percent

9 8 7 6 5 4 3 2 1 0 kW

Daylight-dependent regulation cuts energy consumption by more than 70 percent.

Fig 55: Significant savings – the energy consumption of the

day-light-dependent lighting system (yellow) is a great deal lower than

that of the old system (grey) and the non-regulated new system

(blue) Where daylight is harnessed, the annual electricity

con-sumption amounts to only 5,879 kilowatt-hours.

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Fig 56: Overcast sky in the

morn-ing: the artificial lighting is dimmed.

Fig 57: Adequate daylight at day: the lighting system is almost entirely deactivated.

mid-Fig 58: In the evening and at night, the lighting system is fully activated.

Lighting which is tailored

to human needs, meets

high standards of visual

ergonomy, promotes a

sense of wellbeing and is

good for our health - that

is the main argument for

the use of lighting

electron-ics But quality lighting also

calls for energy-efficient

light generation – a quirement which is met byelectronic operating de-vices: they save energyand cut operating costs

re-It was official even beforethe 1997 Kyoto climateprotocol: emissions of thegreenhouse gas carbon

reduced In Germany, ing accounts for less thaneleven percent of totalenergy consumption butevery kilowatt-hour saved

light-on artificial lighting alsopromotes the cause of cli-mate protection

And the commercial aspectshould not be underesti-mated either: energy costsaccount for around 50 per-cent of total lighting costs;acquisition/installation andmaintenance costs accountfor 25 percent each So thegreatest economies are

achieved by cient lighting

energy-effi-Important facts:

• The luminous efficacy(see page 23) of fluores-cent lamps operated byelectronic ballast (EB) issignificantly higher thanthat of conventionallyoperated lamps So isthe system luminous effi-cacy of the lamp and EB(see pages 18/19)

• EB operation lengthenslamp life and reduceslight depreciation Con-sequently, EB-operatedlamps need to be re-placed less often This

Lighting electronics for conservation and economy

Economy

Ecology

by extending the life of lamps

and operating devices

ance

Mainten-Acquisition and installation Energy

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