BASIC LIGHTING Instructor Doug Avery

Issues K Proper Illumination to perform the task K Occupant Comfort K Energy efficiency K Dispatchable and controlled loads

Overview Lighting Theory Technology –Lamps and ballasts Retrofit Options Controls Field Trips for practical experience

Lighting Theory

Lighting Fundamentals K Definitions Candela: The international unit of luminous intensity. This term has evolved from the consideration of a standard candle as a basis of evaluating the intensity of other light 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 of light 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 Footcandle SquareFoot 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

K 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

K Inverse Square Law: This calculation is used to predict the illuminance at a specific point in space. FC = I/D 2 or FC = Candlepower/distance 2 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 violet A wave 500 Nanometers long is green A wave 580 Nanometers long is yellow A wave 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 produce white light Subtractive Property of Light: Colors added together to produce black--primary colors yellow,cyan, and magenta Other colors created by subtracting from black.

Daylight Cool White White Warm White Candle Light 4,100 3,500 3,000 1,800 Degrees Kelvin Color Temperature 5,000

Measured in light output ( lumens) per unit of power input ( watts) Efficiency

Relative Efficacy Incandescent 8-28 LPW Fluorescent LPW Mercury LPW Metal Halide LPW HPS LPW LPS LPW

TECHNOLOGY LAMPS

INCANDESCENT LAMPS

History K 1879-Thomas Edison invented the first commercial incandescent lamp K 1910-Tungsten filament introducedstill in use today

K 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 used 1935: 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 though a tube filled with low-pressure gas that contains mercury atoms.

Diagram of fluorescent tube

Preheat K First fluorescent lamps were pre-heat K Required a ballast and a starter to operate K Starter pre-heated cathode K 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 ( 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 % 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 T 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 K Relatively new lamp K Better optics, higher lumens K Excellent CRI K Require dedicated fixture –High glare potential K 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 ElectronicMagnetic 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 ballast BF 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 K Conventional Dimming ballasts and controls K Variable auto-transformers K 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 K Lighting systems designed for maintained levels of illumination K Achieve this level during last 1/3rd or useful life of the system K System can be tuned using electronic ballasts and a variety of controls –Exact level of light required –Energy savings

RETROFIT STRATEGIES K Incandescent to Incandescent K Incandescent to Fluorescent K Fluorescent to Fluorescent K Incandescent or Fluorescent to HID K Controls

INCANDESCENT TO FLUORESCENT

FLUORESCENT TO FLUORESCENT

2x4 Troffer o 24” k o 24” k 4 Lamp 3 Lamp 2 Lamp 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 controls K Simple controls K On/off based –Placement of detector is key issue –Little commissioning required –Calibration is straightforward K Advanced controls –Generally require dimming ballasts –Integration of multiple components –Allow integration of all lighting control strategies

LIGHTING CONTROLS K Schedule lighting operation K Occupancy detectors K Sweep off control w/ overrides K Daylight harvesting (other names also) K Lumen maintenance K Load shedding –Real time pricing K Tuning

Scheduling K Predictable K Unpredictable K Daylighting K Brightness balance K Lumen Maintenance K Task tuning K 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 K Measure the amount of light in a space K On/off K Send signals to smart system for daylighting control

Dimming electronic ballasts K Stepped Dimming K Continuous dimming

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