Lighting Controls
A GUIDE TO ENERGY EFFICIENT AND COST EFFECTIVE LIGHTING
Lighting control technology and techniques can significantly reduce lighting energy use whilst
maintaining the quality of illumination. Effective control systems can reduce lighting energy
requirements by between 40% and 60% in most applications.
UP TO
60%
SAVINGS
CONTROLS, 11, 02
ENERGY EFFICIENT AND COST EFFECTIVE LIGHTING
Lighting controls help ensure that lighting is delivered at the right
levels for particular areas or workspaces when required. Up to 60%
of the installed lighting load can be saved with proper use of the
appropriate lighting controls. Lighting controls can be used
for a range of applications such as dimming, presence detection
and to switch off lights when there is sufficient daylight.
LIGHTING CONTROL TECHNIQUES
The main strategies for lighting control include: local switching and dimming, presence detection, daylight linked and time operated.
The following diagram shows effective strategies for lighting control.
LIGHTING
SYSTEM
AUTOMATIC
CONTROL
AUTOMATIC
PRESENCE
CONTROL
DAYLIGHT
LINKED
ON/OFF
PHOTOCELL
ACOUSTIC
MANUAL
CONTROL
TIME
CONTROL
CONSTANT LUX
DIMMING
LOCAL
SWITCHING
PART LOCAL
SWITCHING
TIME
SWITCH
PROGRAMMED
CONTROLLER
MICROWAVE
DYNAMIC
INFRA RED
GROUP
SWITCHING
MOVEMENT
DETECTOR
ULTRA SONIC
INFRA RED
Each zone where lighting controls are to be used should be
evaluated for the best strategy of control. Manual control includes
the way the switches are linked to individual and groups of
luminaires. Controllers can also be automated, and these can react to
presence detection, daylight availability or time of day. Multiple zone
controllers use a communications protocol known as a ‘BUS’ system
to link each component together. The main control strategies are
outlined below.
Manual Control
These are either permanently wired (such as the standard wall
switch), or ceiling mounted pull switches, and can be used for
switching or dimming. Part switching and group switching allows
a certain number of luminaires or lamps to be controlled from local
locations e.g. with appropriate separate ‘zones’, on bright days the
luminaires closest to the windows would not need to be switched
on and would therefore save energy. While manual controls are
cheap to install they still rely on the occupants turning lights off
when they are not needed. Raising awareness of the lighting
requirements and the profile of lighting energy use will be required
to encourage manual switching. This can be done through well
labelled switches and guidelines on what lights are to be used and
when. Responsibility for turning lights on/off outside business hours
needs to be allocated e.g. cleaners or security guards. One Irish retail
chain uses different levels of lighting matched to store activities
or the time of day. Lighting levels are increased in staff entrance
areas during staff shift changeovers and levels are adjusted for store
opening times, cleaning, re-stocking shelves and overnight security.
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Automatic Controls
Presence control
This can be used to:
ƒƒ automatically switch lights on and off as people enter and leave
an area or room
ƒƒ manually switch lights on upon entry and automatically switch
lights off when people leave an area or room.
It is suitable for:
ƒƒ rooms which are used infrequently, such as store rooms,
washrooms, and other small areas
ƒƒ rooms such as class rooms or rooms where the person entering
has their hands free and upon exit has their hands full.
Passive infra-red (PIR) units are low cost traditional presence
detectors which can also have daylight sensor facilities.
Fig.2 Infra-red beam pattern, sufficient
for smaller areas
Some types of PIR sensors can be set to keep the lights off when
there is sufficient natural light and detect presence, automatically
switching the lights on or off when a person enters or exits a space.
Adjustable sensitivity is possible for both presence detecting and
daylight sensing. The Link/Passive infra-red wall mounted (PIRWM)
is a low cost, fast- fit presence detector to replace traditional wall
switches. A built in sensor can be set to keep the lights off if there
is sufficient natural light. This type of product does not require a
neutral connection, so it can easily replace an existing light switch. It
does not have a dimming facility.
Fig.3 Ultrasonic/Microwave beam pattern,
appropriate for larger areas
The mounting position of automatic presence detectors (on the wall
or ceiling) will be determined by the size and shape of the area:
ƒƒ for small areas, infra-red detectors mounted on the wall, as
shown in Figure 2, are likely to provide sufficient detection and
the detector should be able to be ‘seen’ from all positions in
an area
ƒƒ for larger areas, ultra-sonic or microwave detectors, as shown
in Figure 3, are more sensitive to movement and therefore
more suitable for areas where small movements are made. The
direction of the detector head needs to be considered as a sonic
beam will detect movement through glass i.e. outside the office.
The most appropriate mounting position for infra-red detectors is
shown in Figure 1. Be careful not to over space the detectors and
follow manufacturers’ guidance, as not all types have the same
covering pattern.
Daylight linked control
Daylight controls/photocells linked to switch or dimming luminaires
respond to daylight levels. The luminaires in a large workspace could
be split into three lighting control zones. One zone along windows, a
second zone in the middle of the room and a third zone at the back
of the room. The luminaires in each zone can then adjust lighting
levels depending on the natural light entering the space.
Time control
These are used to switch lights off when they are not required, such
as at lunchtime or at the end of the day and in any situation with
a regular period of occupation (always provide manual override to
allow users to switch lights on if necessary).
Range up to 7m
Fig.1 Mounting position for infra-red detectors
CONTROL STRATEGY FOR AN OCCUPIED AND INTERMITTENTLY OCCUPIED SPACE
Person present
Insufficient daylight – lights on
Person present
Sufficient daylight – lights off
No-one present
Insufficient daylight – lights off
2
No-one present
Sufficient daylight – lights off
control aPPLICations
LIGHTING CONTROL STRATEGIES FOR A RANGE OF BUILDING TYPES
Space/Area
Typical Pattern
of Use
Automatic Control Upgrades from Manual Switching
(Control strategies are listed in general order of preference)
Open plan office
Usually occupied
2, 5, 7, 9
Variable occupation
2, 5, 7, 9
Usually occupied
1, 2, 9
Variable occupation
1, 2, 5, 7, 9
Corridors
General
5
Guest rooms
Variable occupation
2, 3, 4, 8
Restaurants and bars
Restaurants and bars
2, 3, 9, 10
Meeting / Conference room with
various activities
Variable occupation
4, 5, 7
Reception or atrium
Usually occupied
2, 9
Canteens
Variable occupation
5, 7, 9, 10
Store rooms, laundry rooms,
photocopying/sorting areas, toilets
Variable occupation
1, 2, 3
Waiting rooms
Variable occupation
1, 2, 3
General classrooms
Usually occupied
2, 3, 4, 9
Variable occupation
2, 3, 4, 9
Laboratories
Usually occupied
2, 3
Warehouses
Variable occupation
6
Retail area
Usually occupied
2, 3, 4, 9
Bookshelf areas
Variable occupation
2, 3, 9
Reading areas
Variable occupation
2, 3, 7, 9
Assembly and sports halls
Variable occupation
6, 9
Sufficient daylight available
Private office
Device
Insufficient daylight available
Lighting guides covering each of these building types are available from SEAI
Automatic daylight sensing to ‘Off’ or ‘Dimming’
Offices
Manufacturing and
Warehouses
Appropriate automatic occupancy sensing
Hospitality Business
Retail
Hospitals
Libraries
Schools
Sports and Leisure
‘Key-fob’ master control
Dimming/scene
setting
Time Operated
3
EXAMPLES OF AUTOMATIC LIGHTING CONTROL DEVICES
1 Passive infra-red wall mounted
6 Microwave*
Functions
Functions
ƒƒ r eplaces the standard
manual switch
ƒƒ presence detection
ƒƒ manual on – auto off
ƒƒ n
o ‘neutral’ connection
is required
ƒƒ daylight sensing to off
ƒƒ 15, 30 & 60 metre range
ƒƒ daylight sensing to off
ƒƒ a uto reduce range to avoid
random switching
ƒƒ 5-9 metre range
ƒƒ 3 to 10 Amp loadings
7 Microwave*
2 Recessed infra-red
Functions
Functions
ƒƒ presence detection
ƒƒ presence detection
ƒƒ manual on – auto off
ƒƒ manual on – auto off
ƒƒ daylight sensing to off
ƒƒ daylight sensing to off
ƒƒ constant lux
ƒƒ constant lux
ƒƒ remote control
ƒƒ remote control
ƒƒ scene set
ƒƒ ‘scene set’ - 6 metre range
ƒƒ 7 metre range
ƒƒ 8 Amp load
ƒƒ 7 metre range
8‘Swipe-card’ or ‘Key-fob’ master
control units
3 Surface mounted infra-red
Functions
Functions
ƒƒ c ontrols the flow of electricity
to room systems
ƒƒ presence detection
ƒƒ daylight sensing to off
ƒƒ a djustable time delay
light sensitivity
ƒƒ remote control
9 Time-operated units
ƒƒ 8 Amp load
ƒƒ 7 - 12 metre range
Functions
4 Combined infra-red detector
Functions
ƒƒ presence detection
ƒƒ remote controller
ƒƒ dimming facility
c an range from simple 7 day
mechanical time switches to
more advanced digital devices
ƒƒ
t hese control power to lamps
based on pre-determined
time intervals
10 Dimmer switches
5 Ultra-sonic*
Functions
Functions
ƒƒ c ontrol light levels by controlling
voltage to the lamps
ƒƒ presence detection
ƒƒ p
re-programmable for time
of day or for ‘scene-setting’ for
general ambience
ƒƒ manual on - auto off
ƒƒ daylight sensing to off
ƒƒ remote control
ƒƒ
* Be aware that these are very sensitive and will detect movement through glass,
for example, someone passing by a window.
ƒƒ 6 metre range
(13 metres in corridors)
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Definitions of terms
Manual on – Auto off, requires the occupant to manually turn on the
lights when entering the space, and the controller will automatically
switch them off when nobody is present in the space.
Daylight sensing to off, the controls will automatically switch the
lighting off when the set level of daylight is reached with a short
time delay in case of a temporary lower level, i.e. passing clouds.
Constant lux automatically dims the lighting (when luminaires have
appropriate dimming ballasts) according to the amount of daylight
that enters the zone. This form of daylight linking provides the
greatest energy savings as the savings relate directly to the dimmed
levels, furthermore the lighting will not suddenly go off.
Remote control enables the lighting to be manually addressed via a
hand held or wall mounted controller.
LAMP DIMMING
Typical energy savings when dimming fluorescent lighting are
shown in Figure 4.
Energy consumption of the tube and ballast (%)
All dimming systems provide energy savings. Ensure that lamp and
luminaire types are suitable for dimming. Some lamp types e.g.
compact fluorescent lamps and high intensity discharge lamps can
be dimmed with appropriate dimming control gear (ballasts).
100
80
60
40
20
0
0
10
20
30
40
50
60
70
80
90
100
Light Output (%)
Fig.4 Typical energy savings when dimming tubular fluorescent lighting.
DAYLIGHT BLINDS
Fig.5 Operation of daylight blinds
on a bright sunny day, and on an
overcast day.
Consider ‘daylight blinds’ for areas that receive good quantities of
natural light, as they can eliminate the need for artificial lighting.
These ‘Venetian-type’ blinds reduce glare and allow daylight to enter
the space in a controlled way.
The lower louvres can be closed to control glare while the upper
louvres can be angled to reflect the sunlight against the ceiling to
illuminate the room evenly, as shown in Figure 5.
If the sky is overcast or clear without the sun the slats can be
adjusted to enable the maximum amount of light to be deflected
into the area and they also enable the occupant to view the outside.
SUMMARY
An effective lighting control strategy will ensure that the level of
lighting provided closely matches the needs of the users of the
space. The installation of lighting controls, such as dimmers, timers,
motion sensors and photocells, or providing comprehensive
switching schedules for manual controls can be a simple and
efficient means of reducing lighting energy use and costs.
A tax incentive is available through the Accelerated Capital Allowance (ACA) scheme for approved
lighting products. Further information and details of manufacturers and suppliers of eligible products
are available from www.seai.ie/aca
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Accelerated Capital Allowance
Eligible Products www.seai.ie/aca