LIGHTING SYSTEM CONTROLS Flashcards
a variety of switches and controls are used to manage operation of lighting installations.
lighting system controls
A __________ is an electrical device that opens an electrical circuit, thereby shutting the lights off or closing the circuit to energize the lighting installation.
switch
switches are a simple on/off switch that controls a
lighting installation from one location.
Single-pole, single throw (SPST)
are required to control a lighting installation from two locations
Two three-way switches
____________ and one or more four-way switch are required to control a lighting installation from three or more locations.
two three way switches
deactivate the lighting circuit after a preset time period has lapsed.
automatic switches
can be used to vary the luminous flux (lumen output) from lamps in a lighting installation.
dimmer switches
limit access to switches for lights and equipment to authorized personnel. They are available with SPST, and capabilities. Often used in lighting installations to provide better control of lighting
keyed switches
can activate a lighting circuit when a door is open or closed
door switches
can be used to control the time period that a lighting installation operates.
time clocks
ꟷ automatically control operation of a lighting installation with electronic
components that are wired into the circuitry.
ꟷ They allow great flexibility as they can easily be set for daily and weekly
cycles.
ꟷ It requires relay switching on larger lighting loads.
electronic timers
sense light and can be used to control night lighting in lieu of a time clock or timer.
photocell controls
control a lighting installation by sensing occupants in a space and usually mounted on the wall or ceiling. Works well in interior spaces such as classrooms and offices.
occupancy sensorS
A __________________________ offers building operators full control of multiple
lighting installations from a single location
central lighting control system
the efficient and effective use of direct, diffuse, or reflected sunlight to provide full or supplemental illumination for building interiors during hours of
sunlight.
daylighting
excellent color rendition and brilliance.
• diminishes the need for artificial light in buildings and thus saves lighting costs up to ___% (in some buildings).
sunlight, 80
strikes a surface and reflects off the
surface in another direction.
ꟷ the receiving surface absorbs some
sunlight before reflecting the light.
reflected light
travels in a straightline
path from the
sun
ꟷ more intense than
diffuse and reflected
sunlight.
direct light
ꟷis light that has been reflected or
refracted by clouds, glazing, or other
objects.
ꟷLess intense than direct and reflected
light and typically results in less glare.
diffuse light
a measure of how easily heat travels through an assembly of materials
Overall Coefficient Of Heat Transfer (U)
Thermal insulating ability is also measured by the thermal __________ (R): a higher R factor indicates a ______ insulating performance.
resistance, better
The R factor is the inverse of the ___ factor
U
• the fraction of solar heat that is transmitted through the glazing and ultimately becomes heat.
Solar Heat Gain Coefficient (SHGC)
In general, _____________ windows in buildings designed for passive solar heating should have windows with a high SHGC to allow in beneficial solar heat gain in the winter.
• _______________-facing windows that receive undesirable direct sunlight in mornings and afternoons should have lower SHGC assemblies.
south facing, east-west
is the percentage of visible light (light in the 380 to 720 nm range) that is transmitted through the glazing.
Visible transmittance
Light-to-solar Gain Ratio (LSG)
is the ratio between SHGC and VT of a single glazing.
• It provides a gauge of the relative efficiency of different glazing types in TRANSMITTING DAYLIGHT WHILE BLOCKING HEAT GAINS
• The higher the LSG ratio the brighter the room is without adding unnecessary amounts of solar heat.
in glazing materials, ______ is used for the outer sheet, where it can provide considerable protection to the plastic, while the inner plastic sheet protects against glass breakage.
▪ Ordinary window glass strongly absorbs the damaging UV portion of sunlight, so a
plastic material will survive longer if it is installed inside glass.
glass
must be designed to provide illumination in areas where it is most needed and to do so without adversely affecting occupant comfort.
daylighting systems
The main functions of _______ are
to bring in daylight and fresh air (if
windows are operable) and
introduce a view of the outdoors.
windows
is a design term that describes
WINDOW size, arrangement, and
glazing type (the glass and
coatings used in the window).
ꟷ it affects daylighting, passive solar
heating, space cooling, and
natural ventilation.
fenestration
is a fenestration arrangement in an upper story wall
that extends above one roof surface; it introduces
daylight into the ceiling area of the space.
clerestory window system
________ is an interior courtyard covered with
glazing. Rooms and spaces 8 adjoining the ______
receive daylight entering through the glazed roof.
atrium x2
are effective daylighting strategies because they introduce daylighting deep into a structure.
atrium and clerestories
In cold climates in the northern hemisphere, the low position of the sun produces a shallow angle and a ________ that contributes to space heating.
heat gain
a slanted south-facing window surface should be avoided because it gains heat all year long and is particularly poor at limiting solar heat gains in the summer.
fun fact
fun?
is a transparent panel located in a ROOF OPENING that allows direct and diffuse sunlight into the building.
- are commonly made from glass, glass composites, plastics, and plastic composites.
skylightS
is a type of skylight system that is a raised, typically triangular shaped, extension of a
roof and that has at least one glazed surface.
- provide large quantities of reflected and diffuse light into the interior of the building.
roof monitor
_____________ can be a favorable application of skylights
warehousing
is a PASSIVE (non-mechanical) architectural
element or mechanism that allows sunlight
to enter DEEP into a building.
ꟷ may be located on the interior or exterior
of the building envelope.
ꟷ Exterior light shelves may also function as
____________ that shade the window from the
high summer sun.
ꟷ Properly designed light shelves allow
daylight to penetrate the interior of the
space up to 21⁄2 times the distance
between the floor and the top of the
window.
reflective light shelveS, overhangs
Most commercially available _________
consist of an _______, roof-mounted
transparent dome, a reflecting _________, and a diffuser for installation at the
ceiling level of the space.
ꟷ It can pass through attic spaces much
more easily.
ꟷ Flexible pipes are easier to install, but
they suffer more light loss from
increased light absorption from reflection
and scatter on the inside surface of the
pipe wall.
light pipeS, exterior, metal pipe
ꟷis a type of light pipe that has a
movable mirror or light-refracting
system and that can be used to align
the incoming sunlight with the axis of
the light pipe, thereby minimizing
reflection losses.
ꟷThe light reflecting apparatus gets in
the way of the whole sky when the sun
is obscured. Another disadvantage is
the need for occasional maintenance.
sun tracking light pipe
Translucent __________________ can be used to introduce daylight through the ROOF ITSELF.
ꟷ The main use for fabric structures has been for sports stadiums, shopping malls, harbors, and airports (Denver International Airport).
ꟷ Fabric structures may be divided into two categories: tension and air supported.
fabric roof membranes
A fabric roof membrane that use a
membrane, supported by air pressure, to act as the roof and walls of the structure
air-supported structures
ꟷPolyvinyl chloride-polyester and
Teflon-coated
basta memoraysa ra
Illuminance of outdoor sunlight: __________ fc
6000
