Transcript Building Operator Certification * Level I for TSTF 32BJ

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:
 If you don’t need it at full power, turn it down.
 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
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
# of Lamps Wattage
#
Fixtures per Fixture per Lamp
101
Fluorescent
12
3
40
Input
Voltage
120
BALLAST
Input
Power
Current
Draw
.84
100w
# 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/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.masonpud3.org/conservation/commerciallighting.aspx
• Linear and CFL
• CFL (“compact”) replaces
directly screws into
incandescent base
• T12 – most common older
version of Linear tube
• Newer versions (T8, T5) 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
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 (%)
50
40
30
20
10
Private Office
Open Office
Conference Room
Computer Room
Restroom
0
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
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.}