NCQLP Study (2011)
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Codes are national, state or local regulations governing (in the case of lighting) minimum requirements for energy usage per sq. ft., occupancy sensors, types of energy conserving equipment etc.
Building Automation System Or Energy Management System
The Building Automation system (BAS) - or Energy Management System (EMS) - typically control HVAC systems and security systems . They can also control lighting using a relay system, although this is fairly expensive (usually $300 to $800 or more per "point" sensed or controlled).
Commissioning is the adjusting and testing of controls (and other equipment) after installation: make sure they work, adjust the device according to manufacture's specifications, listen to occupant feedback and make corrections quickly, encourage periodic maintenance.
energy savings by integrating all of the energy conservation measures (ECM's) into one system.
Daylighting involves a procedure of using daylight to illuminate a space, generally, this requires adding controls to conventional lighting system so that light levels will remain constant against changing atmospheric conditions, Review also "adaptive compensation".
Cooling/Heating & HVAC Effects
The effect of lighting on HVAC "heating" and "cooling" adds to the savings even in cold climates.
The diversity factor adjust the "connected load" to the "actual load" - the fact that some lights would be off even in the absence of advanced controls. This may be true because someone turns off the lights or because of the lamp burnout factor (LBF). Savings should be based on the connected load multiplied times the diversity factor (typically 0.8-0,9).
Dimming can be manual or automatic, Essential it involves lowering the light level and thereby the energy consumption (though not a linear relationship). Automatic dimming can be accomplished using photosensor s with dimmable fluorescent or HID ballasts.
In this instance Electric Rate, helps define the complexity and aggressiveness of the control system You must determine the kWh rate, the kW rate, time-of-day rate adjustment. All will influence the cost-effective nature of the improvement.
Standard rating for touch switches is 1000volt-amperes (VA) at 120 V. "Touch on touch off" switches are electronic and the circuit is not broken by an air gap. In the "off" position a tiny amount of current still flows posing a i hazard to service personnel. Most electronic switches include an air-gap disconnect for servicing.
Effects of Switching Frequencies on Lamp Life
To sum up: Though potential ''lamp burning hours" decrease with frequent switching on/off, "calendar hours" lengthen and energy savings increase. This outweighs any additional cost in relamping.
This is not really a definition as much as an observation. Electronic dimming ballasts have low harmonic distortion, while their incandescent counterparts have high harmonic distortion.
An electronic device that records when lights are on, and when they might be turned off or dimmed. They can sense light in a fixture, monitor current in a switch leg, record occupancy etc.
Lighting controls are devices that turn off or dim lights when they are not needed. They include simple switches, dimmers, occupancy sensors, time clocks, photosensors, and complex building automation systems.
Load Shedding means reducing lighting power and other types of sheddable load (e.g. HVAC) at times of peak electrical demand.
Lumen maintenance means lowering light level when lamps are new and lumen output is higher than needed then gradually increasing to full power at the low end of the maintenance cycle to maintain proper light levels.
Maintenance: essentially keeping the system tuned up and running according to spec over the life of the equipment. It involves making sure sensors work, time clocks sensors and timers are properly set and calibrated, photocells and photosensors are cleaned, related dimming packages ate functioning according to spec.
- Occupancy Sensors are devices which switch Lights on or off' based on detection of motion within a specific or area.
- Types include: Passive Infrared (PIR), Ultrasonic (ULT), Audible, Dual Technology
The Coverage Pattern is the manufacturer's sensor coverage template, diagram, or specification. It helps the designer prescribe the correct sensor for the conditions in a particular room or setting.
Dead Spots include areas of the room or space outside the detection zone of the occupancy sensor. Why?: Sensor range smaller than room, installation not to spec, obstructions in the room, sensitivity set too low.
False Off/False On
- False Off - lights go off when people are in the room: sensor sensitivity set too low, sensor time delay too short, infrared "line-of-sighf" blocked
- False On - lights go on when no one is in the room: motion in adjacent room or hall, hanging objects, mobiles, flags, air currents.
Infrared and Ultrasonic sensors only emit electromagnetic interference (EMI) when switching, just like any other switching device. Ultrasonic sensors may interfere with hearing aids when they use frequencies under 30kHz. In health facilities use 32kHz and above.
High-Low Control refers to dimming fluorescent and HID lighting to a low level, instead of off, when the room or area is not occupied. Dimming to 10-20% for fluorescent and 20% for HID.
Passive Infrared refers to a type of occupancy sensor that detects body heat crossing a detection zone. Lens design determines area of detection.
Emits ultrasound. Frequency shift in the reflected signal signifies motion. Like the Passive Infrared it is triggered by motion. Used in odd-shaped rooms. More sensitive to small motions than PIR "false-ons" can be caused by air turbulence.
Two type of photoelectric controls
Photoswitches — turn lights on or off according to the amount of light striking the sensor. Photosensors - can continuously vary light output, usually by controlling fluorescent dimming electronic ballasts.
Powerline-Carrier System use the ordinary building wiring to communicate between tinitiating devices (time clocks etc.) and the power control devices.
Sweep System refers to a type of relay system. They switch individual lighting circuits on and off at set times. Occupants can override lights on for some period of time, typically one or two hours, using a wall switch or a phone-in signal.
Task Light (Personal Occupancy Sensors)
Personal Occupancy Sensors are used to control a range of devices in a workers cubicle - task lights, computer peripherals, space heaters etc.
Time Clock is an electric clock that has a mechanical dial with trippers attached to open or close an air-gap switch at set times. These are being replaced by electronic versions which do the same thing.
Trial Installation, otherwise known as Installing Samples, helps the designer, the installer' and the customer make a good decision with which everyone has an acceptable comfort level.
Manual User Override
Automatic On/Off - user can use a toggle switch to control lights
Manual On/Auto Off - Lights remain off until occupant switches them on
The use of Baffles and Louvers to shield glare at normal viewing angles, thereby contributing to visual comfort. Parabolic Reflectors are often used for glare control because most of the light is directed straight down. Essentially, glare control is accomplished through shielding the bare light source from direct view.
A ballast is a current limiting device. It is inserted between the discharge lamp and the power supply to limit current flow through the arc discharge. The ballast also provides the correct voltage to start the arc discharge.
Brightness is an experience. We hear someone say, "what a bright day!" and we know what is meant by that. This sensation is only roughly related to the intensity of light entering the eyes. Brightness is a function of the intensity of light falling on a given region of the retina at a ceitain time, the intensity of light that the retina has been exposed to in the recent past (called "adaption") and the intensities of light falling on other regions of the retina (called "contrast").
Candlepower is the measurement of a source in candelas in the direction of the point at a distance from the source to the point on the surface. The basic formula for point source illuminance is: I is the candlepower of the source in candelas in the direction of the point. D is the distance from the source to the point.
Two types of circuits: Series: if one light goes out, they all go out. This is because each lamp is a part of the circuit - lose a lamp, lose the circuit. Must use same wattage lamp. This circuit is considered "load sensitive".
Parallel: if one light goes out the rest stay lit. Various wattage lamps can occur on the same circuit This circuit is not considered "load sensitive".
Coefficient of Utilization
The Coefficient of Utilization (CU) stands for the percentage of light output that is expected from a specific luminaire in a room. It accounts for luminaire efficiency: its ability to deliver light to fee work surface compared to the lumens supplied by the lamp(s). This is the amount of light that is not trapped or lost inside the luminaire. The CU takes into account the reflectance of the walls, the ceiling and the floor. The CU is found on chart by locating the correct Room Cavity Ratio and the correct wall, floor & ceiling reflectance.
Color Rendering Index (CRI)
Color Rendering Index establishes the real or apparent color temperature of a given light source.
Second it establishes a comparison between the color rendition of the given light source and of a reference light source.
If 5000K or less, the reference source is the blackbody radiator at the nearest color temperature.
The given color temperature is above 5000K, the reference source is the nearest simulated daylight source.
Color temperature describes how a lamp appears when lighted. Color temperature is measured by kelvins (K), a scale that starts at absolute zero (-273° C). It is the temperature in kelvins as measured by an imaginary object called a blackbody radiator. Note: Incandescent lamps resemble blackbody radiators in that the emit a continuous spectrum of all of the visible colors of light. Fluorescent and HID lamps produce a discontinuous spectrum with blank areas punctuated by bands at specific frequencies to give the impression of white light.
A fluorescent lamp is a low-pressure mercury arc discharge source. It's operation relies on an electrical arc passing between two cathodes, one at either end of a glass tube. Fluorescent lamps require a ballast to provide the proper starting voltage and regulate the lamp operating current.
When the voltage differs between the two cathodes is sufficient to strike an arc, an electric current passes through the mercury vapor within the bulb. As the arc current passes through fee vapor, it causes changes in the energy level of electrons in the individual mercury ions. As the electrons change levels, they release several wavelengths of visible and ultraviolet energy. These radiations strike the tube wall, where some ofthem cause the phosphor material to fluoresce (become luminous) and emit light.
High Intensity Discharge Lamps
The term high intensity discharge applies to arc-discharge sources with a high-power density. In HID lamps, light is produced by passing electric current through a gas or vapor under high pressure, as contrasted with low pressure fluorescent or low-pressure sodium lamps HID lamps belong to three principal families: (I) mercury vapor, (2) metal-halide, and (3) high-pressure sodium. For a complete description of how each type produces light see the text below and also the three (3) main lamp manufacturers and Venture lamp catalogs
The incandescent lamp is a simple device - a hot wire (the filament) sealed in a glass jar (the bulb). An electric current passing through the wire heats it to incandescence and the wire emits light The filament wire diameter and length determine the amount of electrical curr ent consumed by the lamp, regulating its light output.
Compact Fluorescent Lamps
Compact fluorescent lamps operate like the full-size cousins. The provide high efficacy, high color rendering and 10,000 lamp life in a single ended fluorescent lamp. They operate in the pre-heat and rapid start modes; many have a starter built into the lamp base.
They have significantly higher lumen output per unit length the conventional small fluorescent lamps. This is the result of high phosphor loading which is necessary because of their small diameter and sharp corner multi-shape. Requires a ballast to start & operate properly.
Contrast (also Luminance Contrast)
Use of Luminance Contrast as a Design Technique: Proper attention to the manipulation of luminance contrastas a principal technique for the design of lighting systems results in environments that are inviting and inspiring. Without contrast, the environment produced has the quality of a cloudy overcast day. People feel more alert, energetic and positive on a sunny day, a day marked by bright highlights and crisp shadows.
Daylight has two components: (I) sunlight and (2) skylight. Sunlight is the directional beam emited; by the sun; skylight is the diffuse reflection of light from particles in the atmosphere. Daylight provides stimulus and change. A view of the outside helps provide information about the time of day and weather conditions, thus helping maintain our biological cycles.
National Electric Code (NEC) also (NFPA 70)
National Electric Code (NEC) is document governing safe electrical installation practice as approved by the National Fire Protection Association (NFPA). It is also known by its NFPA designation - NFPA 70
National Energy Policy Act (EPACT)
The U S. Energy Policy Act of 1992 established minimum average efficiency standards for certain incandescent (and fluorescent) lamps.
- A variety of shading devices are employed to deliver daylight to where it is needed; and to reduce glare by limiting excessive luminance in the field of view Shading devices are divided into two categories:
- (1) movable
- (2) stationary
Parabolic Louvers control luminance precisely. They consist of multiple cells with parabolic reflectors, and a specular or semi-specular' finish The cells range in size from 1/2" x 1/2" to 1" x 1"
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