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Lighting systems to save energy

in educational classrooms

Luigi Martirano IEEE memberUniversity of Rome Sapienza

DIAEE Electrical Engineering AreaRome! Italy

luigi"martirano#uniroma$"it

Abstract

In educational buildings

a significant component

of the energy used is

spent in illuminating the

interior of the building.

As the energy costs rise,increasing effort has

gone into minimizing the

energy consumption of

lighting installations.

This effort could follow

three basic directions:

new more efficient

equipment (lamps,

control gear, etc.),

utilization of improed

lighting design practices

(localised tas! lighting

systems), improements

in lighting control

systems to aoid energy

waste for unoccupied

and daylight hours. "y

controlling the lighting

in such a way that the

lighting leel is always

accurately matched to

the actual need allows to

sae on the energy costs

and to improe the

human comfort and

efficiency. #stablishing

an integrated lighting

control concept is a ery

important part of thelighting design process.

The paper describes two

different smart control

systems designed

according the same

concept but with

different components,

for the lighting systems

in two classrooms at the

#ngineering $aculty of

the %niersty of &ome

'apienza. The

installations are realized

according to a researchproect about the

assessment of the impact

of lighting control

systems in electrical

energy consumption and

energy commitments.

The results are useful to

compare the two

different control

approaches

(switching and

dimming) and the

two different !ind of

actions (with or

without luminaries

upgrade) in order to

analyze costs, energy

consumption and

comfort.

The two different

control technologies

are compared with

respect to a third

classroom without

smart control, used

as reference for

ealuations.

Keywords lighting

systems; lighting

controls; building

automation; energy

management

I"I%&R'DU(&I'%

In educational

buildings asignificantcomponent of theenergy used isspent inilluminating theinterior of the

building" In recentyears the EuropeanUnion EU hasactively promoted

political campaignsto)ard energy

efficiency *$+" Anenergeticmanagement

program could befollo) three basicdirections, ne)more efficiente-uipment .lamps!

control gear! etc"/!utilization of improved lightingdesign practices.localised tas0lighting systems/!improvements inlighting controlsystems to avoidenergy )aste forunoccupied anddaylight hours"1uildingAutomation and(ontrol systems.1A(S/ allo)

pursuit ofintelligent energymanagement2 they

provide comple3and integratedenergy savingfunctions based onthe actual use of a

building! dependingon the user4s realneeds to avoidunnecessary energyuse" &he 0ey todesign anintegrated lightingsystem is theelectric lighting

control strategy" Anappropriate lightcontrol systemimproves theoperating efficiencyof a

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building by combining

the electric lighting

)ith daylighting and

real presence of

personnel"

Several lighting control

strategies are availableto manage lightingenergy use in buildings,scheduling! occupancy!daylighting andluminance control arethe most significant" Anappropriate electriclighting control conceptfor a daylight5buildingconsists of a group ofcomponents coherentand integrated in a

certain se-uence" &het)o main componentsare, the integratedlighting control zonesand the control strategyfor each zone" &his

paper concentrates onidentifying theintegrated lightingcontrol strategy ineducational classrooms!ta0ing intoconsideration the

available daylight andthe actual occupancy of

persons in each zone ofthe classroom"&he main strategies ofthe concepts are,

1) to subdivide theclassroom in differentzones )ith differentuses .i"e corridor zone!teacher zone andscholars zone/ and )ithdifferent lu3 values

.zoning strategy/2

2) to schedule thegeneral '%6'77s)itch by a remotecontroller.schedulingstrategy/2

3) to integrate theelectric lights )ithavailabledaylighting in theroom .daylightingstrategy/2

4) to s)itch '77automatically thelights according thereal occupancy ofthe different zones.occupancystrategy/2

5) to organizefi3ed scenariosactivate d bymanual push

buttons .i"e"teaching!

pro8ection! etc"/&he designer has toarrange the controlgroups in order tosatisfy thestrategies abovementioned" In

particular the lightshave to subdivided,a/ in control groups9( according tothe zones2

b/ in regulationgroups 9R constituted by ro)s

parallel respect the)indo)s"&he concept could

be implemented int)o different )ays,

5 by adoptingnormal ballasts and

s)itching mode!useful in cheaprestoration cases25 by adoptingelectronic controlgear and dimmingmode! useful forne) installations ordeep restorations"&he author arranged thelighting controlconcept in t)oclassrooms )ithsame e3tension andsame e3position

but adopting thet)o different )aysmentioned in order

to analyze theinstallation costsand the energeticimpact" A thirdclassroom is usedas benchmar0 value" &he systemis completed byelectrical energymeters andsupervisory systemto monitor thehours of utilization

of classrooms! theelectricityconsumed by thelights and therelated energysavings achieved"&he pro8ect could

be offer helps toorganize referenceguides for futureinstallations andactions ineducational

buildings in orderto save energy"

:;==5"??

B>?$$ IEEE

II"(LASSR''MS

&he t)o classrooms used for

the installations are the

number ; and the number < of

the first floor of the

Enginnering 7aculty of the

University of Rome"

7igure $"

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(lassroom ; and ! 9($" are for zone

$2 9(> is for zone >2 9( is for

zone "

1- Ad8usted in flu3 emittedaccording to the naturalavailable lighting in theclassroom .daylightingstrategy/" At this aim theluminaries )ill be divided in< regulation groups .9R$59R and $? lu3 forone "

2- (onstantly ad8usted only forthe room number ;.luminance control strategy/according to the averagemaintained luminancevalues above mentioned"

window

GR1

GR3 GR2

GR4

GR3

GR5GR4

GR6

GR5

GR7

GR6

GR8 GR7

GR8

7ig" " (lassroom

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&he automatic! manual and

scenario modes could be

enabled by the general

supervisory system located in

the security entrance bo3"

IN" LI9G&I%9('%&R'LAR(GI&E(&URE

&he control is organizedaccording to the G1ESstandards .E% ?$$?/ adoptinga %F system" G1ES systemsare )ith OdistributedintelligenceO as each device is

properly programmed! it has anOaddressO uni-ue in the )holesystem needed to be recognizedas the recipient of the message!scheduled to ma0e an accuratefunction! according to ae3pected mode! )ith anothercomponent of the systemestablished by the program"&he system is programmable

by a H( soft)are system .E&Smode/" &he operation of thesystem is independent of the

presence of a H( or asupervisory system andtherefore it ensures high

reliability" In fact! eachcomponent of the system haselectronic elements in )hichcontains all informationrelevant to the very functioningof the device" In this )ay it isnot necessary to have a central.industrial HL(/ to coordinatecommunication bet)eendevices and for managing theentire operation of the system"&he lac0 of a central element isan undoubted advantage for the

continuity of service2 anyfailure on a device only createsthe inefficiency of the device in-uestion! )hile the rest of the

plant continues to operatenormally"&he system thus created ise3pected to support the systemfor manual control by localcontrol .generic buttons/ orremote controls .buttons ortouch screen/ and a manual orautomatic programmed

scenarios described above"&he system )ill consist of,

1- po)er supply %Fsystem and other %Fdevices2

2- input devices asinterfaces of sensors and %Fsystem and output device

.actuators/ to s)itch theluminaries2

3- occupancy sensors anddaylighting sensors interfaced)ith the %F system using theinput devices"

&he line bet)een %F devicesis provided by a simple t)isted

pair cable"

Classroom number 8 '

")*C+),- %./0

In the classroom number < thetotal flu3 emitted by the systemis regulated by s)itching thesingle ballasts .E(9$ andE(9>/ of each luminaries.switching mode/ in order toguarantee different values of

light, ?P! ?P! $??P .fig"=/"&he control system consists in,

1- > lu3 sensors

2- $ %F input device for thelu3 sensors

3- presence sensors.double technologyinfrared andmicro)ave )ithspecial detector area2

4- $ %F input device for thepresence sensors

5- = %F actuators )ith 3 year/ +

&able II sho)s the LE%I

evaluated for classrooms ; and

< according to the standard

U%I$$:! before and after theactions proposed"

&able II Energetic impact ofactions in classroom ; and ??"

[3] E%$$:Y$ JEnergyperformance of buildings Energyre-uirements for lighting 5 part $,Lighting energy estimationK!March >??"

[4] E% $>==5$ JLight andlighting 5 Lighting of )or0 places 5Hart $, Indoor )or0 placesKStandard >??>

[5] L" Martirano! 9" Harise!Ecodesign of lighting systems!

Industry Applications Magazine!

March5April >?$$! pages $=5$:"

uigi *artirano .StM4:/received the M"S" and Hh"D"degrees in electrical engineeringfrom the University of Rome JLaSapienzaK! Italy! in $::< and >??>!respectively" Ge discussed a HhDthesis on JElectric Ho)er Systems(ircuit HrotectionK" In >???! he8oined the Department of ElectricalEngineering of the University ofRome OLa SapienzaO )here he iscurrently an Assistant Hrofessor"Ge is the author or coauthor ofmore than =? technical publishedpapers and a co inventor of one

international patent" Gis researchactivities cover po)er systemsdesign! planning! safety! home andbuilding automation! protectionand coordination! lighting systems"Ge is a member of the IEEEIndustry Applications Society! ofthe AEI& .Italian Association of

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Electrical and ElectronicsEngineers/ and of the (EI .ItalianElectrical (ommission/ &echnical

(ommittees (&>? and S($$1"Ge has been RegisteredHrofessional Engineer"