Goals of Sustainable Lighting Low Resource Use Energy

Goals of Sustainable Lighting Low Resource Use • Energy efficiency • Reduce GHG (Green House Gas) emissions • Lower operating cost Healthy, High-Productivity Workplace • Good indoor environment – Workplace satisfaction • Increased performance/productivity of occupants • Lighting QUALITY Accomplish BOTH of these objectives.

Efficient Lighting Practices • Use only the energy required to accomplish the task and no more. • Use the most efficient equipment to efficiently produce and deliver the light. • Design the environment to achieve the desired lighting quality for the intended task. • Control the light to reduce run-time: Ø If you don’t need it at full power, turn it down. Ø If you don’t need it at all, turn it off. • Maintain the light to ensure efficient operation and long life.

I. Lighting Terms • The technical name for a light bulb is a Lamp. Fixture/Luminaire • The lamp is installed in a fixture, also known as a luminaire. • Lumens = light output at the source (i. e. the output of a lamp). • Light Level = the amount of light reaching a surface. Measured in “Footcandles” using a Light Meter. S unit is “Lux”, 1 FC = 10 Lux IES Guidelines Lamp Lumens Light Level

Lighting Metrics Watts: Energy input (to a lamp). Efficacy / LPW (Lumens per Watt) Light Output per unit of energy input Lighting Power Density (LPD) (Watts per Square Foot) Rated power input for lighting per unit of floor area Basis of Energy Codes Notice that neither directly considers delivered light level (FC)

Lighting Standards & Energy Codes The Illumination Engineering Society (IES) has developed recommended ranges of illuminance (FC) levels for a wide range of visual tasks. ASHRAE 90. 1: Energy codes are written to place a maximum limit on the allowable LPD in different space types.

Lighting Power Density (LPD): Calculating Energy Usage of Lighting Power Density = Watts per sq foot § Energy Codes are written this way § Codes limit the allowable amount of energy to be drawn by the lighting in a space. § Reflects “design lighting load” in Watts § Lighting Load is rated in Kilowatts. This is the amount of power the lights are drawing “right now” on a “constant draw” basis. § Does NOT take lighting level into account. § Does NOT consider operating hours or, therefore, energy consumption

Exercise: LPD Calculation LAMPS Room Fixture Type # of Lamps Wattage # Fixtures per Fixture per Lamp 101 Fluorescent 12 3 40 Input Voltage 120 BALLAST Input Power Current Draw. 84 100 w # per Fixture 1 84’ 28’ LPD = Energy (Watts) Area of Room (sf) 7

II. Lamp Types Incandescent Standard - filament type based on pure resistance Tungsten-Halogen High Intensity Discharge (HID) Mercury Vapor Metal Halide High Pressure Sodium Low Pressure Sodium Fluorescent Linear Compact (CFL) Light Emitting Diode (LED) Also other emerging technologies such as Photoluminesence Common lamps are organized into major families, depending on the way the light is produced.

Efficacy of Different Lamps Source: http: //www. ecmag. com/section/lighting-design-101

Incandescent • Very low EFFICACY. • Being phased out. • Can be directly replaced by CFL’s. CFL replacements are often part of “free” energy improvements offered through utility-sponsored energy efficiency programs.

Fluorescent http: //www. masonpud 3. org/conservation/commerciallighting. aspx • Linear and CFL • CFL (“compact”) replaces directly screws into incandescent base • T 12 – most common older version of Linear tube • Newer versions (T 8, T 5) are more efficient • Ballast controls voltage & current.

Ballasts A ballast is an electrical device that performs two functions: • Starts lamps by providing initial high voltage to strike an arc between electrodes. • Regulates light output by maintaining normal operating current and voltage. Fluorescents and HID both use ballasts. Ballasts are NOT generally interchangeable between lamps. Incorrect ballasts can reduce lamp life and/or light output, if they start the lamp at all. Old Ballasts – Electro-mechanical – Low Frequency 60 Hz. Oldest may contain hazardous PCP New Ballasts – Electronic Solid State – High Frequency 5000 Hz

Reading Fluorescent Lamp Specifications When comparing, lamp ordering codes and labels vary by manufacturer but similar abbreviations and codes systems are used. For more information: www. gelighting. com/na/business_lighting/education_resources/literature_library/catalogs

High Intensity Discharge (HID) • Also “gas-discharge” – produces visible light by passing an electric current through a mixture of gases. • As the lamp warms up, the gas pressure increases and the light gets brighter. • Typically used for outdoor or high-bay applications. • Types: • • High-pressure sodium Low-pressure sodium Metal Halide Mercury Vapor (no longer recommended, being replaced by sodium or metal halides).

LED (Light Emitting Diode) • Traditionally used for exit signs and street lamps. • Increasingly be used to replace fluorescents and incandescents. • Waste heat rejection is important consideration – inadequate heat rejection shortens LED life. • Long live, 50, 000 burn-hours. Energy impact unclear – 50% < LFl ? The illustrations above are LED linear fluorescent replacements that are also manufactured in colors.

Section 3: Lighting Controls More effectively controlling the light goes beyond energy savings: Cost savings > Eliminate unneeded light > Extend lamp life Security > Automatic vs. Manual switching > Motion Detection / Occupancy Sensing Lighting Quality > Match appropriate light level to task > Provide for increased Visual Comfort – Daylighting

Circuiting - When designing floor plans for lighting all of the lights that serve the same basic function in the same general area will be put on the same circuit. Because of the limits of the load that can be placed on a lighting circuit breaker, typically 15 amps, a large area may need several circuits. Lighting and convenience or equipment circuits are generally kept separate. > These limits present opportunities. If the owner wishes for all of the lights to be controlled by a single switch, a relay can be used to tie all of the circuits together. These separate circuits can be used for different control strategies to meet differing use and conservation needs. > Completely on and off.

Bi-Level Switching § Two levels of light brightness are possible § High Level is used during occupancy § Low level is used when not occupied Lamps in the fixture are on different circuits and switches

Scheduling Time clocks Programmable lighting control panels that can operate stand -alone or can be integrated into broader building control systems

Occupancy Sensors Typical Energy Savings (%) Occupancy sensors change the light depending upon use (when people are present). Notice the savings go up if the room is used intermittently. Storerooms, warehouses, school rooms and corridors would also benefit from occupancy control. The new Energy Code of NY City requires the use of the Sensors. Two Types: Passive Infrared (PIR) and Ultrasonic

Dimming desirable for many applications Special Ballasts required for fluorescent dimming Manual dimming o Incandescent easy to dim o Dimming by resistance device does not save energy o o The resistors heat up and the light energy becomes heat energy. Fluorescent - needs dimmable ballast Automatic dimming o By schedule o When unoccupied o When daylight available

Daylighting – various ways to introduce daylight Top Lighting – Skylight Side Lighting Light Shelf – High on Window Light Shelf – Low on Window High Reflectance Ceilings Transoms also called “Borrow Lights” located over the doors and high on the walls shared light between perimeter and core spaces Minimize glare of direct sunlight

Daylight variation Why do artists’ studio windows face north?

Daylighting Control (“Daylight Harvesting”) Control systems • Dimmer Control to maintain a constant level of light in the room. • Measures the light level, and responds. • Without adequate control of artificial lighting, daylight savings will NOT be realized. Operational Issues • Avoid “hunting” {hunting is when the sensor reacts too quickly and the variation in the output of the light becomes noticeable} How do you know if it’s working? {if you cover the photosensor you will see a reaction from the lights} • Differential control for perimeter vs room interior {You want the lights near the windows, where the quantity of natural light is greater, to be dimmer than the lights on the interior. }