basic lighting instructor doug avery. issues k proper illumination to perform the task k occupant...

BASIC LIGHTING

Instructor

Doug Avery

Issues

Proper Illumination to perform the task

Occupant Comfort Energy efficiency Dispatchable and controlled

loads

Overview

Lighting Theory

Technology– Lamps and ballasts

Retrofit Options

Controls

Field Trips for practical experience

Lighting Theory

Lighting Fundamentals

Definitions• Candela: The international unit of

luminous intensity. This term has evolvedfrom the consideration of a standard candleas a basis of evaluating the intensity of otherlight sources

• Candlepower: A term used to describe

the relative intensity of a source

Definitions

Lumen: This is the international unit of

luminous flux. One lumen is the amount oflight striking a one-square-foot area, all points of which are 1 foot away from a point source of 1 candela intensity.

• Footcandle: This is the unit of measure

of the density of light striking a surface. One footcandle = 1 lumen striking 1 square foot.

1 FootcandleSquare Foot

Foot Candle

• Footlambert: This is the unit of

measure of light exiting a surface.

• Frequency : The number of complete

cycles a wave makes in one second

• Hertz: Cycles per second

More definitions

Average illuminance:This calculation predicts the average

foot-candles in a space.FC = Lm/Sq.Ft.Example: 5,000 lumens of light evenly spread over an area of 100 sq.ft.5,000 Lm/100 sq.ft. = 50 fc.

Fundamental Lighting Relationships

Inverse Square Law:This calculation is used to predict the illuminance at a specific point in space.FC = I/D2 or FC = Candlepower/distance2

If intensity is 2,000 candelas at a distance of 10 feet, the illuminance will be:

FC = 2,000 CD / 10 ft.2 = 20 fc

Another valuable formula

Light is a form of radiant energy that is capable of exciting the retina and producing a visual

sensation.

Nature of Light

The color of a light wave is determined by its length

A wave 380 Nanometers long is violetA wave 500 Nanometers long is greenA wave 580 Nanometers long is yellowA wave 620-760 Nanometers long is red

Light and Color

White light is:

A relatively balanced combination of wave lengths

Created by the blending of the primary colors of lighting: Red, Green, and Blue

Additive Property of Light:Colors added together to producewhite light

Subtractive Property of Light:Colors added together to produceblack--primary colors yellow,cyan,and magenta

Other colors created by subtracting from black.

Daylight

Cool White

White

Warm White

Candle Light

4,100

3,5003,500

3,0003,000

1,8001,800

Degrees Kelvin

Color Temperature

5,000

Measured in light output ( lumens)

per unit of power input ( watts)

Efficiency

Relative Efficacy

Incandescent 8-28 LPWFluorescent 45-105 LPWMercury 40-100 LPWMetal Halide 60-115 LPWHPS 50-140 LPWLPS 60-150 LPW

TECHNOLOGY

LAMPS

INCANDESCENT LAMPS

History

1879-Thomas Edison invented the first commercial incandescent lamp

1910-Tungsten filament introducedstill in use today

Measured in light

output ( lumens) per unit of power input ( watts)

Incandescent Lamps

– This is the ratio of total lumens to total power input.– The theoretical maximum efficacy of tungsten is 52 lumens per watt.– Efficacy increases as lamp wattage increases, however it also decreases as lamp life increases.

Efficacy

– Filled with iodine or bromine gas.– Has regenerative cycle where the

tungsten molecules go to the bulb wall--combine with the iodine or bromine, which do not adhere to the bulb wall--tungsten is redeposited on filament.

Halogen Cycle Lamps

Halogen Lamps

WHAT ARE SOME GOOD APPLICATIONS FOR INCANDESCENT

LAMPS?

THE WORK HORSE OF LIGHTING

FLUORESCENT LAMPS

History

1896: Edison applies for patent--never used1935: G.E. introduces a green lamp at IES conference.1938: First commercial fluorescent lamps

introduced.

Theory of operation:

Gaseous discharge lamps that produce light by discharging an electric arc

thougha tube filled with low-pressure gas that contains mercury atoms.

Diagram of fluorescent tube

Preheat

First fluorescent lamps were pre-heat Required a ballast and a starter to

operate Starter pre-heated cathode Very slow, usually a few seconds to start

the lamp

Instant start (Slimline) circuits

– Introduced in 1944 to overcome the slow start of the pre-heat lamps– High voltage (400 - 1000 volts) jump start

the lamp– Typically slim-line lamps since external cathode heating is not necessary

Rapid start circuits

– Introduced in 1952 to combine the advantages of both the pre-heat and instant start circuits.

– Require external heating of the cathodes, therefore use bases with two electrical contacts-- Medium bi-pin and recessed double

contact

T-8 LAMPS VS T-12 LAMPS

WHICH ONE IS THE RIGHT ONE?

F40T12 34 W CW LAMP

• 465 ma lamps operated on a 430 ma ballast• approximately 85 - 87% ballast factor 2900 initial lumens X 85% BF= 2465 lumens• approximately 37 watts (lamp and e.s.ballast)• only difference between std 40WF40 and 34W F40 is krypton gas fill• T12 diameter traps light• thermal losses

32 W T8 4100 K LAMPS

• 265 ma lamp operated with 265 ma ballast• average 91% ballast factor 2900 initial lumens X 91% BF = 2639 lumens• 11% improved efficiency due to high frequency Phosphors love high frequency• tri-phosphors permit better quality of vision

• T-8 size permits more light to exit fixture

T-5 LAMPS

Relatively new lamp Better optics, higher lumens Excellent CRI Require dedicated fixture

– High glare potential Significant energy savings

Ballasts

Ballasts limit current and provide proper voltage to the lamps they operate.

All lamps should be operated on the ballast that was designed for that specific lamp type.

Ballasts

Ballast Comparison

Electronic Magnetic

High frequency

Low heat

Adaptable for control

(dimming and day-lighting)

May cause some RFI,

(Library scanners and simplex)

Harmonics .20<

60 Hertz

High heat

Can not dim

No RFI

Harmonics .25<

Ballast Factor

This term refers to the percentage of rated lamp lumens that will be produced when the lamp is operated on a particular commercial ballastBF X rated lumens= Effective lumens

The Controversy:

Instant Start vs Rapid Start

BALLASTS

INSTANT

WHICH ONE IS BEST?

RAPID

Immediate on

Uses 1.5 watt less

Can not Dim

Can reduce lamp life

Slight delay

Need to maintain cathode heat ( +1.5 watt energy use)

Able to dim

Maintains rated lamp life at less than 3 hours per start

Fluorescent Dimming

Conventional Dimming ballasts and controls

Variable auto-transformers Electronic dimming ballasts

– Stepped dimming– Continuous dimming

Daylight Harvesting

Two strategies:– Turn off lights in

day-lighted area– Use dimming

ballasts and photoreceptors

Lumen Maintenance

Lighting systems designed for maintained levels of illumination

Achieve this level during last 1/3rd or useful life of the system

System can be tuned using electronic ballasts and a variety of controls – Exact level of light required– Energy savings

RETROFIT STRATEGIES

Incandescent to Incandescent Incandescent to Fluorescent

Fluorescent to Fluorescent

Incandescent or Fluorescent to HID

Controls

INCANDESCENT TO FLUORESCENT

FLUORESCENT TO FLUORESCENT

2x4 Troffer2x4 Troffer

o 24” o 24” k k

4 Lamp4 Lamp

3 Lamp3 Lamp

2 Lamp2 Lamp

3 3/4”3 3/4”

Fixture Comparisons

There are times when the best solution is a NEW

fixture

INCANDESCENT OR FLUORESCENT TO HID

Lighting Controls

Categories of controlsCategories of controls Simple controls On/off based

– Placement of detector is key issue– Little commissioning required– Calibration is straightforward

Advanced controls– Generally require dimming ballasts– Integration of multiple components– Allow integration of all lighting control

strategies

LIGHTING CONTROLSLIGHTING CONTROLS

Schedule lighting operation Occupancy detectors Sweep off control w/ overrides Daylight harvesting (other names

also) Lumen maintenance Load shedding

– Real time pricing Tuning

Scheduling

Predictable Unpredictable Daylighting Brightness balance Lumen Maintenance Task tuning Load Shedding

Occupancy Sensors

OCCUPANCY SENSORS are used to automatically control the lights in a space. Infrared Ultrasonic Combination of both

Occupancy Sensors

If not properly installed, calibrated and commissioned, occupancy sensors tend to disabled

Photoreceptors

Measure the amount of light in a space

On/off Send signals to

smart system for daylighting control

Dimming electronic ballasts

Stepped Dimming

Continuous dimming

Control Strategies

Employee awareness Optimal on/off sweeps Daylight harvesting Lumen Maintenance Remote control