nibm - lecture - three
TRANSCRIPT
-
8/3/2019 Nibm - Lecture - Three
1/23
BUILDING SCIENCE for INTERIOR DESIGNLecture three natural &
artificial lighting24.10.2011
Archt. RANGASOYSA. BSc[BE],MSc[Arch],AIA[SL]
-
8/3/2019 Nibm - Lecture - Three
2/23
BUILDING SCIENCE for INTERIOR DESIGN
Lighting designTime duration two lectures
Out line
1. Source of light
2. Lighting metrics
3. Lighting terms
Tutorial :
1- advantages and disadvantages of natural lighting
-
8/3/2019 Nibm - Lecture - Three
3/23
BUILDING SCIENCE for INTERIOR DESIGN
Sources of LightNeed for artificial lighting :
1. Absence of natural lighting
2. To compensate for low levels of natural lighting
-
8/3/2019 Nibm - Lecture - Three
4/23
BUILDING SCIENCE for INTERIOR DESIGN
Types of light sources1. Incandescent
i. General service
ii. halogen
2. Low pressure discharge
i. Florescent
ii. Low pressure sodium
3. High pressure discharge
i. Mercury vapor
ii. High pressure sodium
-
8/3/2019 Nibm - Lecture - Three
5/23
BUILDING SCIENCE for INTERIOR DESIGN
Incandescent lampsLight produced by filament heated to
incandescence by an electric current.
Discharge lamps
Light produced by the passage of electrical currentthrough a vapour of gas.
Ultraviolet lighting phosphorus Generate light
-
8/3/2019 Nibm - Lecture - Three
6/23
BUILDING SCIENCE for INTERIOR DESIGN
General service lampsProperties :
1. Lamp construction2. Shape
3. Efficiency
4. Operating characteristics
-
8/3/2019 Nibm - Lecture - Three
7/23
BUILDING SCIENCE for INTERIOR DESIGN
General service lamps1. Lamp construction
Glass enclosure soda lime / Clear or frosted
Inside filled with gas [ argon or nitrogen ]
Reduce lamp blackening caused by filament evaporation
Filament tungsten
Propertiesi. High strength
ii. high ductility
iii. High melting point
iv. Low evaporation
v. Favorable radiation qualities
-
8/3/2019 Nibm - Lecture - Three
8/23
BUILDING SCIENCE for INTERIOR DESIGN
-
8/3/2019 Nibm - Lecture - Three
9/23
BUILDING SCIENCE for INTERIOR DESIGN
General service lampsSupport wires - copper or nickel plated
Base - made of aluminum or brass
conducts electricity to filament
holds lamp at socket
3. Lamp efficiency
Increase with wattage high luminance at high watts
[ 5W, 10W, 15W , 25W, 40W , 60W , 75W, 100W, 125W
-
8/3/2019 Nibm - Lecture - Three
10/23
BUILDING SCIENCE for INTERIOR DESIGN
-
8/3/2019 Nibm - Lecture - Three
11/23
BUILDING SCIENCE for INTERIOR DESIGN
General service lamps4. Operation characteristics
1. voltage variation effects to life cycle, lamp out put, efficiency
[General voltage in sri lankan and other countries ]
2. burning position base up vs base down
3. usage residential, retail, theatrical , art galleries
4. average rate : 750 1000 hrs
-
8/3/2019 Nibm - Lecture - Three
12/23
BUILDING SCIENCE for INTERIOR DESIGN
-
8/3/2019 Nibm - Lecture - Three
13/23
BUILDING SCIENCE for INTERIOR DESIGN
General service lampsTypes of incandescent lamps :
1. General service :
common residential application
Typically A and PS types
Screw type and pin type
Between 10W to 1000W
2. Reflector type lamps :
R type reflector
ER type elliptical reflector
PAR type parabolic aluminum reflector
life span 2000 hrs
Less efficient than general service lamps
Usage spot lighting , flood lighting and projection
-
8/3/2019 Nibm - Lecture - Three
14/23
-
8/3/2019 Nibm - Lecture - Three
15/23
BUILDING SCIENCE for INTERIOR DESIGN
General service lampsDisadvantages :
1. Relativity short life span
2. Poor maintains at voltage tolerance
10-15 % tolerance reduce 75 % of life space - [ need of stabilizer ]
3. Inefficient only 10 % of wattage [ energy ] uses as light.
4. High heat effects fire hazards
-
8/3/2019 Nibm - Lecture - Three
16/23
BUILDING SCIENCE for INTERIOR DESIGN
Florescent lampsMechanism :
1. Voltage is applied across the electrode
2. current runs through the cathode wire to heat tungsten and emissive
material.
3. Electrons are emitted from the cathode and accelerated towards the
anode by the electric field across the electrode [ this creates arc ]
4. Electrons collide with mercury atoms and cause them to emit UV
radiation.5. UV radiation is converted by prospers in to visible radiation.
-
8/3/2019 Nibm - Lecture - Three
17/23
BUILDING SCIENCE for INTERIOR DESIGN
Florescent lampsConstruction :
1. Bulb :
shapes
Diameters
Inner surface coated with blend phosphorus
2. Electrodes
Located at each end of the lamp [ cathode and anode ]
Coiled tungsten wire coated with alkaline earth material
3. Gas
Mercury vapor
4. Ballast - choke
Electric pulse [ high voltage ]
5. Base - conducts electricity to cathode and holds lamp in socket
-
8/3/2019 Nibm - Lecture - Three
18/23
BUILDING SCIENCE for INTERIOR DESIGN
Florescent lampsProperties :
Life span 12000 hrs 24000 hrs [ at 3 hours continues burn ]
Voltage variation :
Affects lamp life
Increase and decrease coloration
Lower lumen maintenance
Low operating cost
Ambient temperature : optimum lumen output at 77 F [ 25C]
-
8/3/2019 Nibm - Lecture - Three
19/23
BUILDING SCIENCE for INTERIOR DESIGN
Florescent lampsTYPES
1. Pre heat
electrodes are pre heated for 5 sec before the start
Starting switch is unreliable
Lamps are interchangeable with rapid start lamp
2. Instant start
No preheating required
Arc is created with by applying high starting voltage
High starting voltage reduce lamp life
-
8/3/2019 Nibm - Lecture - Three
20/23
BUILDING SCIENCE for INTERIOR DESIGN
Florescent lampsTYPES
1. Pre heat
electrodes are pre heated for 5 sec before the start
Starting switch is unreliable
Lamps are interchangeable with rapid start lamp
2. Instant start
No preheating required
Arc is created with by applying high starting voltage
High starting voltage reduce lamp life
-
8/3/2019 Nibm - Lecture - Three
21/23
BUILDING SCIENCE for INTERIOR DESIGN
-
8/3/2019 Nibm - Lecture - Three
22/23
BUILDING SCIENCE for INTERIOR DESIGN
Lighting related termsLamp - transforms electricity to visible light
Luminaries - complete lighting unit
Efficacy lumens per watt
Efficiency - luminaries to lamp lumens
Power budget total lighting power on a project [ watts ]
Power density - watts per square density
-
8/3/2019 Nibm - Lecture - Three
23/23
BUILDING SCIENCE for INTERIOR DESIGN
Lighting related termsVoltage - [ V ] electrical potential [ pressure ] measured in volts
Current [ I ] Flow of electrons measured in amps
Resistance [ R ] oppose flow of electrons / friction measured in oms
Power [ P ] energy consumed to perform work, measured in watts
Energy [ E ] power consumed to perform work measured in watts