A Lighting Audit - Assignment Example

Lesson s The purpose of the is to learn the information needed to do a lighting audit. Considerations in choosing types of lighting in aworkplace setting: Task At Hand You need to consider what work is going to be done because various types of work require different lighting types. There are many different types of lamps and they vary in how well they render color and the lighting quality. Color Rendering affects the quality of light. Light has various qualities. One of these qualities is the Color Temperature. Some lamps make everything look cool (blue light) while other lamps render colors in a fashion more similar to natural lighting. Others emphasize warm colors in the red spectrum. Age of Workers The human eye perceives light differently as we age. Seeing text for older workers is more difficult than for younger workers. Cool, high quality light can create eye strain while the same if true if lighting is too warm. The age of the workers is important when considering the type of lighting chosen. Efficacy of the Lamp A lumen is a measure of visible light and a watt is an measure of energy. The lumen/watt ratio gives an indication of how much light is produced per amount of energy input. This is not a measure of lighting quality, but a measure of efficacy (efficiency). Lamp Types Incandescent lights lose most of their energy input through heat. They only convert about 10% of their energy input into lumens. The rest is lost through heat. Halogen lights are better at converting lumens due to the reflective qualities built into the lamp. They are still quite inefficient at converting lumens from energy input. Compact Fluorescents are much more efficient than Halogens and Incandescent. They operate at a cooler temperature. They also produce a cooler light. Regular Fluorescents are even more efficient than Compact Fluorescents. High Pressure Sodium and High Pressure Metal lights are usually used for outdoor lighting. Some of these lights can be modified to work in setting such as big box stores so that the quality of lighting is better and has better color rendering. These modification make the lights less efficient, however. The unmodified lights are much more efficient than either type of Fluorescent, but the light quality is low. Mercury Vapor lights were some of the first High Pressure lights, but they are almost extinct due to low efficacy and replacement by Low Pressure Sodium lighting. Low Pressure Sodium lights are used for outdoor lighting. They have the highest efficacy (lumen/watt) rating of all types of lights. Life Cycle of the Lamps Incandescent lights have a very brief lifecycle when compared to Low Pressure Sodium lights. Incandescent last about 750 hours while Low Pressure Sodium lights last about 24,000 hours. Savings/Conservation In a typical office work environment, 40% of the operating cost for the physical environment is to support lighting. Having the correct type of lighting is important, but using the most efficient lighting is very important as well. These two consideration must balance one another. Lesson #2 Notes Considerations when working with ballasts Remember that a ballast is a regulator; it regulates voltage for the startup of the lamp. Electronic ballasts have mostly replaced the magnetic ballasts that were first used in fluorescent lighting. Total Harmonic Distortion Electronic ballasts can add to this. This can be a problem because it will interfere with other electronics affected by linear distortion. The ideal is to be lower than 20% but 32% is acceptable. The only real thing you can do to reduce THD is to pay for electronic ballasts that produce less THD. This is viewed as a market problem, and manufactures will only make electronic ballasts with lower THD when the demand is there. Compact Fluorescents can have a range of up to 180% THD, but this is not the norm. Electromagnetic Interference This happens rarely but can be very frustrating when it does happen. Electromagnetic Interference can happen when electronics that are sensitive to this sort of interference will not work due to the electromagnetic field created by the ballasts used in the lighting. Professor gave an example of a copy machine in a library that would not work due to this. It worked when the lights were off, not when they were on. They simply replaced the machine. Considerations when installing or retrofitting lighting systems. For improved efficiency, there are three basic approaches that can be taken. One way is to reduce the watts per fixture. To accomplish this you would replace lamps with less efficacy, such as Mercury Vapor lights or Incandescent lights, with lights that produce more lumens per watt. This is why many companies and individuals wishing to increase their efficiency and lower utility costs have switched to fluorescent and Low Pressure Sodium lighting. A second way that increasing efficiency can occur is to use fewer fixtures to accomplish the task at hand. This may involve removing lighting that has been determined to not contribute to accomplishing the task at hand. The level of lumens in a given area may also be able to be reduced with no detriment to worker productivity or safety if several lamps are removed. Removing lamps is a very quick way to save but must not compromise safety, quality or the accomplishment of the task at hand. A third way to achieve better energy efficiency is to reduce the number of hours a fixture is in use. This can be accomplished in many ways. Human behavior is difficult to change so several types of controls have been developed so a mechanical means of control can be used to lower hours of usage for any given fixture. Types of Controls Electronic means of reducing the numbers of hours the fixture is turned on is the job of controls. Timers, movement sensors, occupancy sensors and photo sensors are all passive types of controls. Dimmer switches are active controls that do not reduce the amount of time but alter the amount of watts being used to operate the fixture on a per hour basis. Lesson #3 Notes Occupancy Sensors Infrared sensors detect body heat. When no heat is detected, then the lights in the room will go out. This works by sensing a change in body heat from one zone to another. Zones spiral out from the sensor. Dead zones are possible with this type of occupancy sensor but it does have the advantage of being cheaper than ultrasonic sensors. Ultrasonic Sensors detect movement is a manner similar to sonar. The ability of the sensor to detect movement diminishes with distance. Movement on the outer edge of the sensor’s area of detection needs to be more drastic than movement near the sensor to activate the lights. Occupancy sensors have limitations. They do not work well in areas with lots of obstructions. Infrared sensors will work in a classroom that is occupied with desks and tables, but will not work in an area where there are obstructions such as cubicles or filing cabinets. Ultrasonic detectors will still work in areas like these, but will be limited in places with large obstructions such as libraries with large stacks of books. Timers These are popular controls for areas with very fixed uses. Retail and manufacturing areas that are unoccupied at set times that do not vary. A concern with times is trapping workers in the dark if they are working off hours. Safety issue. Environmental Concerns with Lamp Conversions Lamps contain many materials that can be harmful if disposed of improperly. Mercury is one of the most harmful substances used in Fluorescent lamps. Mercury can leach out of landfills. It can be recycled. One way to help control this is to require luminaries companies to certify how they dispose of the lamps they replace. Newer lamps contain less mercury. Ballasts also have environmentally damaging substances in them. PCB’s are in old ballasts, but have been banned in California since the 1970’s. Light Emitting Diodes (LED) lights are exciting technology that have the potential to change the future of lighting. LED lights operate without mercury so that is an advantage over fluorescents. They are also very efficient. They are being used in niche lighting areas but have not been able to move into general lighting yet. There are some places, such as in a Phillips lighting factory that LED lights are being used as general purpose lighting in canister form, but this is not economically viable unless you are an LED manufacturer. Stability and efficiency are bright spots for LED bulbs. Day lighting This architectural innovation has been used for a long time. Traditional ways of providing natural light for indoor spaces include windows and skylights. This is easy for residential dwellings but harder for large buildings and factories. Solar tubes and light pipes allow light to penetrate even very large buildings. Reflective properties of these features allow sunlight into indoor spaces. This is difficult to retrofit but can be incorporated into the design of new factories and other large structure. Read More