PowerSave Schools Tool Kit Manual

Transcription

1 Alliance to Save Energy s PowerSave Schools Tool Kit Manual Written by Bill Gabler and Leslie Comnes

2 Contents Introduction... 3 Correlations to Science Education Standards... 4 PowerSave Schools Tool Kit Contents... 5 Background Information for the Teacher... 6 About the Tools Surge Protector Light Bulb Socket Infrared Thermometer Light Meter Flicker Checker Watt Meter Tool Kit Activities Lighting Comparing Light Bulb Temperatures Comparing Light Bulb Outputs Measuring Light at Different Distances Assessing the School's Lighting Levels Magnetic or Electronic Ballasts Determining the Energy Costs of Exit Signs Heating, Ventilation, and Air Conditioning Too Hot or Not? - Thermostat Check-Up Investigating Heat Loss through Walls Computers, Appliances, and Motors How Much Electricity Does It Use? General Energy Usage Analyzing the School's Annual Electricity Usage School Energy Audit Alliance to Save Energy s PowerSave Schools Program 2

3 Introduction PowerSave Schools is a comprehensive program designed for K-12 schools that creates energy awareness, enhances experiential learning, and saves schools money on energy costs. Schools spend more on energy than on computers and textbooks combined. Reducing energy use is an effective way to help cash-strapped schools funnel more money into the classroom instead of the local utility. Just as important, the concept of energy efficiency provides multidisciplinary learning opportunities in science, math, computer skills, and language arts. Through the program materials, students learn how to assess energy-use behavior, monitor the effects of behavior change, and track resulting energy and cost savings. The PowerSave Schools Tool Kit is designed to help you and your students investigate energy consumption at your school using professional, state-of-the-art testing equipment. The Tool Kit enables students to collect real data about energy use and waste at the school site and help them evaluate the meaning of the data. This manual will help you get the most of the PowerSave Schools Tool Kit. It describes what each tool is for, how to use it, and what students can do with it. It also suggests activities that make use of the tools for learning about the school's building energy, including lighting; heating, ventilation, and air conditioning; appliances, motors, and other devices; and general energy use. There are many other investigations that your students might propose, once they understand that energy works as a system within a building. Please share these ideas with us so that we can provide them to other Tool Kit users. For more information about the Tool Kit, contact the PowerSave Schools Program at the Alliance to Save Energy, (510) Alliance to Save Energy s PowerSave Schools Program 3

4 Correlations to Science Education Standards National Science Education Standards The activities described in this manual help to teach toward the following National Science Education Standards. Science as Inquiry, Content Standard A As a result of activities in grades 5-8 and 9-12, all students should develop Abilities necessary to do scientific inquiry Understandings about scientific inquiry Physical Science, Content Standard B As a result of their activities in grades 5-8, all students should develop an understanding of Properties and changes of properties in matter Motions and forces Transfer of energy As a result of their activities in grades 9-12, all students should develop an understanding of Structure and properties of matter Motions and forces Conservation of energy and increase in disorder Interactions of energy and matter Science in Personal and Social Perspectives, Content Standard F As a result of activities in grades 5-8, all students should develop understanding of Populations, resources, and environments Science and technology in society As a result of activities in grades 9-12, all students should develop understanding of Natural resources Environmental quality Science and technology in local, national, and global challenges History and Nature of Science, Content Standard G As a result of activities in grades 5-8 and 9-12, all students should develop understanding of Science as a human endeavor Nature of scientific knowledge Alliance to Save Energy s PowerSave Schools Program 4

5 PowerSave Schools Tool Kit Contents* Surge Protector Light Bulb Socket (4) Infrared Thermometer (MiniTemp) Light Meter (Pocket Foot-Candle Light Meter) Watt Meter (KILL-a-WATT) (2) Flicker checker Duffle bag Tool Kit Manual *Tool Kit contents may vary depending on the version that is ordered for your district. For more information, contact your local project leader or the PowerSave Schools Program at the Alliance to Save Energy, (510) Alliance to Save Energy s PowerSave Schools Program 5

6 Background Information for the Teacher Strapped with aging buildings and ever-increasing energy costs, our nation's K-12 schools are challenged to serve expanding student populations with ever-tightening budgets. Every year, K- 12 schools consume a total of $6 billion in energy. Although space heating is important, electricity makes up 72% of education energy costs and lighting represents 56% of electricity costs. The good news is that many low- and no-cost changes can make a dramatic impact on a school's energy consumption. By some estimates, the average school uses about 25 percent more energy than is necessary. Reducing this waste can return real dollars to the school budget, freeing up more money for salaries and school supplies. Many of the same changes that help lower energy costs can also improve the classroom environment and increase students' ability to learn. A recent study conducted by the California Board of Energy Efficiency shows that student test scores were 15% to 26% higher in classrooms that used natural lighting rather than artificial lights. It makes sense that students who are more comfortable, in classrooms with lighting and air temperatures at appropriate levels, perform better in school. More important than saving money at an individual school, reducing energy has an impact on our society as a whole. Energy production and use account for nearly 80 percent of air pollution, more than 88 percent of greenhouse gas emissions, and more environmental damage than any other human activity. It also affects our natural security: the United States imports even more oil now than it did during the oil crisis of the late 1970s. Preventing energy waste can benefit the environment by reducing pollution and conserving our natural resources. What is Energy Efficiency? Energy efficiency means getting the most from every energy unit by reducing waste and using energy wisely. The goal of energy efficiency is to get the desired energy services comfortable homes and schools, profitable businesses, convenient transportation with less energy use, less air pollution, and lower total cost. It often relies on state-of-the-art technologies to provide daily needs in the most economical way. For example, installing programmable thermostats that automatically turn down the heat when the building is not in use provides substantial energy and cost savings. For schools, homes, and small businesses, energy efficiency means using less energy to heat, cool, light, and power the building. How Can Schools Be More Energy Efficient? The tools in the PowerSave Schools Tool Kit will enable students to evaluate the school's energy use in the areas of lighting, heating/cooling, and computers and other devices. These areas have a potential for the greatest energy savings. Used by energy auditors and other specialists to assess a building's energy uses, the tools can help students propose strategies that help their school save energy. The tools can also be used to assess how well these strategies, once implemented, have worked. In general, the lowest cost options involve turning things off, turning things down, and cleaning and maintaining existing systems and appliances. Medium-term solutions, such as upgrading lighting or capital improvements, require more up-front costs but can dramatically increase the Alliance to Save Energy s PowerSave Schools Program 6

7 energy efficiency of the school building. In looking at cost-effectiveness, students should understand life-cycle costs and that a school is constructed with an expected life span of 50+ years. Lighting Some schools use up to 35 percent of their energy consumption for lighting. Much of that energy may be wasted because there may be more lights than necessary, the lights may be left on longer than they are needed, light bulbs and types may not be the best for a specific use, or the lighting may be dirty or inefficient. Turning off. There are several ways schools can reduce lighting energy. The simplest is to turn off lights that are not being used. As students conduct a general audit of the school's energy use with the Tool Kit, they may find situations where unneeded lights are kept on. For example, special-use rooms such as the auditorium or cafeteria might be lit when no one is using them. Occupancy sensors, which automatically turn off lights when the space is not in use, can help. However, a no-cost alternative is to train staff to turn off lights and assign students as energy monitors to be sure that lights are switched off. Turning down. Another no-cost strategy is to reduce the amount of electric lighting and make use of natural sunlight where possible, so that there is an appropriate amount of light. Many schools and offices waste energy by having more light than is needed in certain areas. Illumination is measured in foot-candles, one foot-candle being a lumen of light distributed over one square foot of surface area. 1 The ideal illumination is the minimum amount of light necessary to do a task comfortably, efficiently, and safely without straining the eyes. For classroom tasks, foot-candles is adequate; for restrooms, foot-candles is adequate; while foot-candles is sufficient for corridors and stairways. Using the PowerSave Schools Tool Kit, students can measure the illumination in different areas of the school and compare it to their local building codes for each task area. Longer-term solutions. Replacing standard incandescent bulbs with compact fluorescent light bulbs (CFLs) can save 60 to 75 percent of the energy cost of a particular fixture. While CFLs use substantially less energy than incandescents, they produce an equivalent amount of light, measured in lumens. With the PowerSave Schools Tool Kit, students can compare the energy used and the light output of various bulbs and calculate the potential energy savings of replacing bulbs (called "relamping"). Students can also test to see whether the school has magnetic fluorescent ballasts or newer electronic ones, which are more comfortable and more efficient. Relamping with modern T8 fluorescent lamps that include electronic ballasts can reduce lighting energy consumption by 35 percent. Heating and Cooling The heating and air conditioning system is often the largest energy consumer in a school. Even modest improvements in system efficiency can represent relatively large savings in a school's operating budget. In some ways, a school building is like a hot cup of tea. If you set down the tea, it will get cold. The same is true for the school building. If you turn off the furnace on a cold night, the building 1 The metric unit of illumination is lux, with one lux being equal to one lumen per square meter. Alliance to Save Energy s PowerSave Schools Program 7

8 will get cold. That is because heat tends to move from warmer areas to colder areas, in this case moving from the building to the outside air. Warm air may also leak out through cracks in the walls or ducts or around windows. The heating system is designed to provide heat at about the same rate it is being lost. The more heat that radiates or leaks out of a building, the more energy will be required to keep it warm. Air conditioning systems use more energy when heat either leaks or radiates into a building from the outside. Students can use the PowerSave Schools Tool Kit to look for inexpensive ways to save energy for heating and air conditioning. After looking for sources of heat leaks and energy waste, they may recommend such things as plugging leaks in ducts or around doors and windows, making sure the thermostat is accurate, using programmable controls to set the thermostat, keeping doors and windows closed when using the system, rebalancing duct louvers for better efficiency, closing window shades, or planting trees to reduce the need for air conditioning. Turning down. Using the PowerSave Schools Tool Kit, students can evaluate the temperature and usage of various areas in the school, and make appropriate recommendations for turning down the settings. Lowering the temperature settings after school hours and on weekends can mean significant energy savings. However, staff must be sure that after-school activities, such as sports events or theater productions, are not affected. In areas of the school that are used only at specific times (such as auditoriums or cafeterias), turning down the temperature during nonuse times also makes a lot of sense. Cleaning and maintenance. Many heating systems run higher than is necessary simply because the thermostats are inaccurate. Students can use the Tool Kit to check the thermostat to be sure it is accurate. They can also test the air-conditioning temperatures comparing the temperature of the air going to the air conditioner to that of the air coming out of the register nearest the air conditioner. If the difference is less than 14 F or greater than 22 F, a technician should inspect the unit to be sure it is in tune. Longer term solutions. Commissioning is a process in which building engineers observe a building to ensure its systems are operating appropriately and efficiently. Using the Tool Kit, if students find that the heating ducts are greatly imbalanced or that there are other such system problems, commissioning may be a possible option for the school. Studies have shown that monitoring a building's energy systems can lead to 10 to 15 percent reductions in energy bills, mostly from resetting existing controls to increase energy efficiency and comfort. Commissioning can cost between 5 and 40 cents per square foot. If your school is planning a comprehensive renovation of the heating and cooling system, involve students in the process. Many school districts target their most inefficient systems first, and then use the energy savings they enjoy to fund other capital improvement progress. Students can use the Tool Kit to help identify where the greatest inefficiencies lie, and research energysaving alternatives such as geothermal heat pumps and evaporative cooling, for making a recommendation for replacement. Computers, Appliances, and More The economic boom in our society and the growth of new technologies has dramatically increased the number of products that require power in the average school or home. Schools Alliance to Save Energy s PowerSave Schools Program 8

9 today may have multiple computers and printers, copiers, TVs, CD players or cassette decks, and VCRs, as well as overhead projectors, electric pencil sharpeners, refrigerators, microwaves and more. Computer equipment is the fastest growing area of electric consumption in the world. Turning off. Much of the energy used for computers is wasted because they are kept on while not in use. A computer left on 24 hours a day uses $224 a year in electricity. The monitor uses 80% of a computer s energy, so turning the monitor off will lead to significant energy savings. Furthermore, many idle appliances like TVs, VCRs, cable boxes, cordless phones, and microwaves continue to consume energy even when they are switched off. This energy keeps display clocks lit and memory chips and remote controls working. Lawrence Berkeley National Laboratory calculates that idle TVs and VCRs alone cost U.S. consumers more than $1 billion a year. Students can use the PowerSave Schools Tool Kit to assess how much energy is used by the appliances and devices in the classroom. From the data they collect, students will be able to make recommendations on how to save energy, such as making sure that photocopiers, computers and printers are switched off at night and on weekends. Turning down. Soda vending machines eat up a lot of energy. Using the PowerSave Schools Tool Kit, students can analyze the amount of energy these machines use, and make recommendations for reducing it. Two possibilities are to remove some of the large fluorescent lights, or to add an "energy monitor" that can reduce the amount of energy used by the machine; soda manufacturers will often pay for this simple device if asked. Learning More By using the Tool Kit, students will learn life-long skills in evaluating energy usage, developing recommendations and making choices. They will also gain a first-hand understanding of building systems and how they work. The activities described in this manual are meant to be a springboard for your own ideas. We hope that you and your students will want to explore more deeply areas that we have just touched upon. Alliance to Save Energy s PowerSave Schools Program 9

10 Sources The following sources were used in developing this Background Information: "Five Ways Students Can Save Energy: Department of Energy Kicks Off Earth Day 2002," About.Com. Downloaded on July 28, 2003 from Krigger, John. Residential Energy: Cost Savings and Comfort for Existing Buildings. Helena, MT: Saturn Resource Management, "Managing Energy Costs in Schools," Wisconsin Public Service. Downloaded on July 28, 2003 from "Our Schools Are Failing Energy 101," U.S. Department of Energy, Building Technologies Program. Downloaded on July 29, 2003 from "Why Is Energy Efficiency Important?", National Renewable Energy Lab. Downloaded on July 28, 2003 from "Why Teach About Energy?", U.S Department of Energy's Office of Energy Efficiency and Renewable Energy. Downloaded on July 28, 2003 from Alliance to Save Energy s PowerSave Schools Program 10

11 About the Tools* *Note: Always use precaution and common sense whenever using the tools with students. Surge Protector What's It for? The surge protector can be used for plugging in multiple electronic devices, and specifically with this toolkit, it can aid in calculating and comparing electrical usage. How to Use It Plug the surge protector into the watt meter or a standard wall outlet. Make sure that the switch is in the Off position until you are ready to begin using it. Safety Warning Use indoors and in dry locations. Not for use with aquariums or other water-related products. What Students Can Do Using a watt meter, students can measure the amount of electricity one or more light bulbs use. Care and Storage Be sure to unplug the device after use. Store it in a cool and dry place. Light Bulb Socket (4 included in kit) What's It for? The light bulb socket can be used in place of a lamp. How to Use It Screw in a light bulb* and then plug it into an outlet, surge protector, or a watt meter. Safety Warning Do not use a bulb of 660 watts or greater. Be careful of electrical shock; do not touch the inside of the socket when it is plugged in. The socket may be hot after use. Do not get the device wet and use indoors only. What Students Can Do Using a watt meter, students can measure the amount of electricity a light bulb uses. Care and Storage Be sure to unplug the device after use. Store it in a cool and dry place. *Light bulbs not included. Alliance to Save Energy s PowerSave Schools Program 11

12 Infrared Thermometer (Mini-Temperature Gun) What's It For? An infrared thermometer measures the surface temperature of an object by sensing its emitted energy, reflected energy, and transmitted energy. This information is collected by the sensor, directed into a detector, and translated by a microprocessor into a temperature reading that is displayed on the unit. It can be used to check for heat leaks through walls, windows, or ducts. How to Use It 1. Point the unit at the object to be tested. Keep in mind that the infrared thermometer measures just the surface temperature of an object. It also works best on surfaces that are not shiny or polished metal. 2. For better accuracy, hold the infrared sensor within a few inches of the object you want to measure. 3. Push down on the larger of the two buttons to turn on the device and to get a temperature reading. Hold down the button to get a continuous real-time reading. 4. Read the temperature of the object on the LCD display. The temperature reading will remain on the screen for 15 seconds after the trigger is released. After 15 seconds, the device automatically turns off. 5. You may set the unit for either 0 F or 0 C. To change the setting, click the Mode button, which is the smaller of the two buttons on the device. What Students Can Do Measure the temperatures of various light bulbs to see how their heat output relates to energy efficiency (see Comparing Light Bulb Temperatures, p. 28, and Determining the Cost of Exit Lights, p. 40). Measure the temperature on the inside of exterior walls to see if there is heat or cold coming through them anywhere (see Investigating Heat Loss through Walls, p. 48). Look for heat leaks by checking the temperature at duct joints or by looking for temperature differences in the return and supply ducts of the heating, ventilation, and air conditioning system. Measure the wall temperature in different rooms to see if the heating, ventilating, and air conditioning system is balanced. Check the windows for heat transfer. Alliance to Save Energy s PowerSave Schools Program 12

13 Check to see if recessed lighting and exit light bulbs are incandescent or energy efficient. If they are hot, they are most likely incandescent. If the fixture is cooler they are likely fluorescent or LED. Check the temperature of heating pipes running through the room. If the room is always too hot, uninsulated heat pipes may be at fault. Measure the temperature at various places in a working motor to find out how efficiently it works (see Measuring Motor Efficiency, p. 53). Care and Storage Keep the infrared thermometer away from temperature extremes (hot or cold) and electric sources. The thermometer should not be used around arc welders, induction heaters, static electricity sources, or other areas with high levels of electromagnetic fields. The unit should not be stored in an area where temperatures drop below freezing (it makes the plastic case more susceptible to cracking). Do not use solvents to clean the plastic lens. Instead, clean it by blowing or brushing off loose particles, or wiping it with a water-moistened swab. If the battery is replaced, be sure to properly dispose of the old battery. Remind students not to point the device in another person s face. Tell them to aim below the head area. Alliance to Save Energy s PowerSave Schools Program 13

14 Light Meter (Pocket Foot-Candle Light Meter) What's It For? A light meter measures (in foot-candles) the light level of a given area or work surface. It tells how much light is actually reaching the work surface where it is placed and can be used to determine whether there is too much or too little light there. Safety Warning To avoid electrical shock, disconnect the external measuring terminals before replacing the battery. How to Use It 1. Turn on the light meter, making sure the sensor is covered. 2. If you are inside, you ll probably want the Range selected to A because the foot candle reading will be less than 200. If you re outside or in a very bright area, select Range B to pick up foot candles of more than Press the Zero button. Make sure the display shows zero (0). If not, hold the "Zero" button until it does. 4. Remove the sensor cover. 5. Read the lighting level. Readings should be taken at the level where the work occurs. For example, in a hallway the reading should be taken on the floor; in the classroom it should be taken on the desk; at a computer it should be taken at the keyboard or monitor. To find the light level for a whole room, measurements should be taken around the room (window, door, chalkboard, desk) and averaged. What Students Can Do Compare the light output of an incandescent light bulb to a compact florescent light bulb (see Comparing Light Bulb Outputs, p. 31). Measure light levels at different distances from a source to determine appropriate light levels (see Measuring Light at Different Distances, p. 34). Measure the light in different areas of the school to find out whether they are appropriately lit (see Assessing the School's Lighting Levels, p. 36). Check local building codes to see whether the school's lighting meets or exceeds these levels. Compare light levels for various tasks. In general, less light is needed when the task can be done at a slow rate or does not require accuracy, when the contrast between the item and the background is great, and when the person doing the task is young. Alliance to Save Energy s PowerSave Schools Program 14

15 Care and Storage Always remember to switch the Power to Off after use. The battery compartment is located on the back lower section of the meter and may be opened by preying open with cover with a small coin or screwdriver. Replace the battery with a heavy-duty 9V battery. Properly dispose of the used battery. The light meter sensor is fragile, so handle with care. Store the light meter in its original box. Flicker Checker What's It For? The Flicker Checker tests fluorescent lights to determine whether they have magnetic or electronic ballasts. It does so using the principle of a stroboscopic effect to detect the light's cycle speed, showing a pattern if the ballast is magnetic and a blur if the ballast is electronic. Fluorescent lights operated by a magnetic ballast turn off and on 120 times per second. While this flickering is not usually discernible to the human eye, it does have a subliminal impact on the human brain and can cause varying levels of disorientation, headaches, and even nausea. Fluorescent lights operated by an electronic ballast cycle off and on thousands of times per second. This faster cycle rate of lights with electronic ballasts does not cause a visual or subliminal effect on people. How to Use It 1. Spin the Flicker Checker like a top on a flat surface under the light fixture to be tested. 1. Watch the top of the Flicker Checker for a discernible checkered or chopped pattern. If there is a pattern, the ballast in the fixture is magnetic. If there are only smooth circles, the ballast is electronic. What Students Can Do Students can test the fluorescent lights at school to find out if they have magnetic or electronic ballasts (see Magnetic or Electronic Ballasts?, p. 32). If magnetic, students might encourage the school administration to switch to electronic. Care and Storage Avoid rubbing or scraping the patterned surface of the Flicker Checker, as this will destroy the pattern. Alliance to Save Energy s PowerSave Schools Program 15

16 Watt Meter (KILL A WATT: 2 included in each kit) What's It For? A watt meter measures the amount of electricity an appliance or other object uses. By plugging any standard 120 volt appliance or electronic device into the meter, you can get a complete analysis of current draw, incoming voltage, cost of operation, run time and more. Safety Warnings Do not touch the watt meter if it is wet. The unit is not water resistant. Use the watt meter indoors only. Never open the case or puncture the plastic overlay above the liquid crystal display. If the case breaks or other physical damage is apparent, do not use. Do not exceed the maximum ratings as detailed on the label. How to Use It 1. Plug the watt meter into a standard wall outlet. The unit will start to accumulate KWH and powered duration time (hour) after power is applied. Then just plug in the appliance you want to measure. 2. Select the correct button to collect the desired electrical usage data. Press the "Volt" button to show the line voltage. Press the "Amp" button to show the current being drawn by the appliance plugged into the meter. Press the "Watt/VA" toggle button once to display the instantaneous wattage currently being consumed by the device or appliance. Press the button again to display volt amps. The LCD will display watts as the active power, whereas VA is the apparent power. Press the "Hz/PF" toggle button once to display the frequency of the output voltage (output is in Hertz). Press the button again to show the power factor, which is a comparison of the active and apparent power (PF=W/Vrms Arms). Press the "KWH/Hour" toggle button once to display the cumulative energy (kilowatt hours) consumed by the appliance or device since the meter was plugged in. Press the button again to show the elapsed time since power was applied to the unit. 3. Consumption will be displayed in Kilowatt-Hours (from 0.01 KWH to 9999 KWH). Time will initially be displayed as Hours:Minutes (from 00:00) and switch to Hours (to 9999). Counters will recycle to zero when they reach their maximum. To reset, remove power from unit momentarily. Alliance to Save Energy s PowerSave Schools Program 16

17 What Students Can Do Find out which items in the room use the most energy (see How Much Electricity Does It Use, p.51). Calculate how much it costs to run all the appliances and electronics in the room for a given amount of time (see How Much Electricity Does It Use?, p. 51) Find out how much energy various items in the room consume even when they are not being used. Compare the wattage a device consumes to the number of watts it is supposed to use each hour (see Comparing Light Bulb Temperatures, p. 28). Wattage ratings are often listed on the product. Students can also look for a tag that lists the volts and current (in amps), and multiply the voltage by the current (amps) to get the wattage rating per hour. Determine whether replacing standard light bulbs with compact fluorescent ones would save money. Care and Storage Do not clean the watt meter with any liquids. If necessary, use a soft cloth to clean the case. Do not take the unit apart. Store the unit in a cool and dry place. Unplug it when it is not in use. Alliance to Save Energy s PowerSave Schools Program 17

18 Tool Kit Activities* *(Some of these lessons are also included in the Road Map Guide for both Primary and Secondary Students.) Alliance to Save Energy s PowerSave Schools Program 18

19 Comparing Light Bulb Temperatures Objective Students will measure the temperatures of various light bulbs to find out how their heat output relates to energy efficiency. Equipment Infrared thermometer* Watt meter* 3 incandescent light bulbs in a variety of wattages (at least one in the watt range) 1 compact fluorescent light bulb (15-20 watts) A desktop light fixture with a standard light bulb socket Safety gloves * From PowerSave Schools Tool Kit Safety Warning Use safety gloves when changing the light bulbs as they will be hot and can burn. Advance Preparation You may plan to do the Comparing Light Bulb Outputs activity, p. 31, at the same time as this investigation. Leading the Investigation 1. Explain to students how incandescent light bulbs work: The tungsten filament is heated to red hot so that it glows. Point out that only 10 percent of the energy used to run an incandescent light actually goes to lighting the bulb and that the other 90 percent is wasted as heat. Tell students that the investigation will help them determine any relationship between the wattage of light bulbs and how much heat they lose. 2. Follow the procedure described on the student page, conducting this investigation as a class demonstration or as a lab station set up for students. Follow-Up Students can survey the fixtures around the school to make a preliminary evaluation of their efficiency. They may compare fluorescent lights, exit lights, gymnasium lights, auditorium and stage lighting, and recessed lighting fixtures. They may need to use binoculars to read the labels and wattages on light bulbs in ceiling fixtures. Alliance to Save Energy s PowerSave Schools Program 19

20 Student Page Comparing Light Bulb Temperatures Question Is there a relationship between heat output and wattage in light bulbs? Your prediction: Equipment Infrared thermometer Watt meter 3 incandescent light bulbs in a variety of wattages 1 compact fluorescent light bulb Desk lamp with standard light bulb socket Safety gloves Safety Warning Use safety gloves when changing the light bulbs as they will be hot and can burn. Procedure 1. Plug the watt meter into the wall outlet and then plug the lamp into the watt meter. 2. Insert the lowest wattage incandescent light bulb into the lamp. Turn on the lamp. 3. With the watt meter in the wattage mode, record the wattage being consumed by the light. Use the infrared thermometer to measure the temperature of the bulb shell. Every minute after that for five minutes, monitor and record the actual watts and bulb temperature. 4. After turning off the lamp, carefully remove the incandescent bulb using the safety gloves. 5. Repeat the process with each of the light bulbs, ending with the compact fluorescent light bulb (CFL). Data 0 min. 1 min. 2 min. 3 min. 4 min. 5 min. Bulb #1 Wattage rating: Actual watts Bulb temp. Bulb #2 Wattage rating: Actual watts Bulb temp. Bulb #3 Wattage rating: Actual watts Bulb temp. Bulb #4 (CFL) Wattage rating: Actual watts Bulb temp. Analyzing the Results Alliance to Save Energy s PowerSave Schools Program 20

21 1. How does bulb wattage or bulb style relate to the amount of heat generated? 2. Did the actual wattage consumed match the rating of the light bulb? (Possible reasons for not matching include variations in the size of the filament during production runs, poor quality control by the manufacturer, or differences between the rated voltage and the actual voltage.) 3. Which bulb is the most energy efficient (loses the least amount of heat)? 4. What else did you learn from the investigation? Alliance to Save Energy s PowerSave Schools Program 21

22 Comparing Light Bulb Outputs Objective Students will use a light meter and a watt meter to compare the energy use and light output of an incandescent light bulb and a compact fluorescent bulb. Equipment Light meter* Watt meter* Desk lamp with standard light bulb socket 1 incandescent light bulb of watts 1 compact fluorescent light (CFL) bulb of watts * From PowerSave Schools Tool Kit Background Information A typical incandescent bulb may seem cheaper than a compact fluorescent light (CFL) bulb because it costs $1.00 or less compared to $2.00 to $5.00 for a CFL bulb. However, if you compare the life cycle cost, CFLs are more economical than incandescent bulbs. CFLs are much more energy efficient and last much longer than incandescents. Incandescent bulbs waste 90 percent of the energy they consume as heat and generally last only 750 to 1,000 hours, compared to 10,000 hours for CFLs. That means that you will need 10 incandescent bulbs to equal the life of one CFL. If you include in the life cycle cost the costs to manufacture, package, transport, stock, sell, and dispose of 10 incandescent bulbs compared to 1 CFL, the savings are even greater. Incandescent bulbs and CFLs also differ in terms of the light they emit. Incandescents emit large amounts of light in the yellow/orange spectrum, but almost none in the blue range. CFLs, by contrast, use a mixture of phosphors to ensure that a broader spectrum of the color spectrum is emitted and most CFLs emit the full spectrum of light. However, when asked which provides better quality light, people will offer different opinions. Some prefer the warm yellow of the incandescent and others prefer the clear white of the CFL. Note: CFLs should be recycled and not put in the landfill or incinerator. Advance Preparation You may choose to do this investigation in conjunction with the Comparing Light Bulb Temperatures activity, p. 28. Leading the Investigation 1. Introduce the investigation by sharing with students some of the information presented in the Background Information section. 2. Follow the procedure described on the student page, conducting this investigation as a class demonstration or as a lab station set up for students. Follow-Up Alliance to Save Energy s PowerSave Schools Program 22

23 Have students compare the life cycle cost of the two light bulbs. First, find out the cost of each type of light bulb. Next, have students calculate how many kilowatt hours of electricity each type of light bulb will consume over 10,000 hours (the rated life of a CFL). For example, 75 watts x 10,000 hours = 750,000 watt hours = 750 kwh. Then, students use your local electrical rates to determine the cost of operating each light bulb over 10,000 hours. Discuss any additional cost of purchasing and replacing 10 of the incandescent light bulbs for each CFL. Students add up all the costs and determine which is a better buy. Alliance to Save Energy s PowerSave Schools Program 23

24 Student Page Comparing Light Bulb Outputs Question How does the energy usage and light output of an incandescent light bulb compare to that of a compact fluorescent? Your prediction: Equipment Light meter Watt meter Desk lamp 1 incandescent light bulb 2 compact fluorescent light (CFL) bulbs Safety gloves Procedure 1. Plug the watt meter into the wall outlet. 2. Put the incandescent light bulb into the lamp socket. Plug the lamp into the watt meter and turn on the lamp. 3. With the watt meter in the wattage mode, record the wattage being consumed by the light. 4. Use the light meter to measure the output of the light bulb. 5. Turn off the lamp and, using gloves, carefully remove the incandescent light bulb from it. 6. Repeat the procedure using the compact fluorescent light bulb (CFL) in the lamp socket. Wait 1 or 2 minutes for the bulb to warm up before measuring the wattage and the light output. Data Measured Wattage Incandescent Bulb Compact Fluorescent Bulb Light Output Analyzing the Data How did the light bulbs compare in terms of measured light? How did the light bulbs compare in terms of measured wattage? Alliance to Save Energy s PowerSave Schools Program 24

25 Measuring Light at Different Distances Objective Students will use a light meter to measure the visible light that reaches different distances from a light source as a way to determine appropriate lighting levels. Equipment Light meter* Desk lamp with a watt fluorescent light bulb, or other light source Measuring tape * From PowerSave Schools Tool Kit Background Information The amount of visible light decreases rapidly the further one moves from the light source. The relationship between the distance from a source of light and its apparent intensity is governed by the inverse square law for light. This law states that as the distance between a source of light and its sensor doubles, the light appears to become one quarter as intense. Likewise, as the distance between a source of light and its sensor is halved, the intensity of the light appears to quadruple. Advance Preparation Set up a flat surface, clear of obstacles, that is approximately 2 meters in length. This may be a workbench, two tables positioned end-to-end, or any other combination of items to create the surface. Position the light source at one end of the surface and mark ½ meter, 1 meter, and 2 meters away from it. Leading the Investigation Follow the investigation as described on the student page, conducting it as a class demonstration or as a lab station set up for students. Alliance to Save Energy s PowerSave Schools Program 25

26 Student Page Measuring Light at Different Distances Question How does the distance from the light source affect the amount of light? Your prediction: Equipment Light meter Desk lamp with a watt fluorescent light bulb, or other light source Measuring tape Procedure 1. With the light source turned off, set the light meter sensor at the 1 meter point and position it to measure the light source. Take and record the background light level. 2. Turn on the light source and record the light level at 1/2 meter, at 1 meter, and at 2 meters. 3. Subtract the background light level from the reading taken at each of the measured marks. Data Background level (light source turned off) 1/2 meter from light source 1 meter from light source 2 meters from light source Measured Light Corrected Readings (Measured Light - Background Level Analyzing the Data 1. What happens to the amount of visible light as the distance gets greater? 2. How does doubling the distance affect the amount of visible light? 3. What is the relationship between the distance from a light source and the amount of visible light? 4. What does this investigation tell you about the optimal place to put a light source? 5. How would this placement save energy? Alliance to Save Energy s PowerSave Schools Program 26

27 Assessing the School's Lighting Levels Objective Students will use a light meter to determine whether the school is appropriately lit. Equipment Light meter* Building code lighting specifications for the community in which the school is located * From PowerSave Schools Tool Kit Background Information The level and quality of a school's lighting can have a direct impact on learning. When rooms have dull, gray light, it is difficult to see and to learn. The amount of light needed for a task depends on a number of factors, including: The age of the person doing the task. The younger the person, the less light is needed. The speed with which the task is to be done. The slower the task can be done, the less light is needed. The size of the item or the task. The larger the item, the less light is needed. The amount of contrast between the item and the background. The greater the contrast, the less light is needed. Experts have calculated what the lighting levels should be for each type of room in a school or business. These levels are specified in building codes that are followed by architects as they design a facility. Typical light levels for various areas are: Corridor and Stairways foot-candles Conference and Reception Areas foot-candles Classrooms foot-candles Restrooms foot-candles When using the light meter, put the meter at the surface level where the work takes place. For example, in the hallway, meter readings should be taken on the floor because that is where the work (walking) takes place. In the classroom, readings should be taken on the desk because that is where the work (reading) takes place. Leading the Investigation Follow the investigation as described on the student page, conducting it as a class demonstration or in small student groups. Follow-Up Discuss the results of the investigation. If there is room for improvement in the lighting or energy use, what might the class recommend? For example, if students removed one light bulb or tube out of each fluorescent fixture and light levels remained within standards, the class may recommend leaving it like that. Alliance to Save Energy s PowerSave Schools Program 27

28 If students recommended removing light bulbs, they can calculate how much energy would be saved. For example, if they recommend removing 27 light bulbs rated at 34 watts each and these lights are normally operated 200 hours per month, they would multiply: 34 watts x 27 x 200 hours = watt hours, or kwh (kilowatt hours). From their calculation of kwh savings, students could calculate the monthly dollar savings by multiplying that number by the local rate of electricity per kwh. They could also calculate the amount of savings in emissions. National average figures for emissions are: 1.48 pounds carbon dioxide (CO 2) per kwh pounds sulfur dioxide (SO 2 ) per kwh pounds nitrous oxide (NOx) per kwh milligrams mercury (Hg) per kwh This site from the EPA may help you determine more specific rates for your local utility: Alliance to Save Energy s PowerSave Schools Program 28

29 Student Page Assessing the School's Lighting Levels Question Does the current lighting in specific areas of the school meet or exceed what is considered adequate for these areas? Your prediction: Equipment Light meter Building code lighting specifications for the community in which the school is located Procedure 1. Use the light meter to measure the light levels in a variety of rooms and hallways around the school, for example classrooms, bathrooms, foyers, and offices. Record your findings on the back of this page. 2. Compare the measured light levels to the levels required by your state codes. How do the light levels at the school differ from the code requirements? 3. If you have time, you may want to change the parameters and repeat the measurements. For example, you might measure the light under different conditions (a sunny day, a cloudy day, or at night). Or, you might ask your teacher to have the custodian remove one light bulb or fluorescent tube from each fixture in a classroom; then repeat the measurements. Analyzing the Data Take a look at the data you have collected and see if there are any trends or patterns. Consider the collected data and compose a list of recommendations. Alliance to Save Energy s PowerSave Schools Program 29

30 Magnetic or Electronic Ballasts? Objective Students will use the Flicker Checker to determine whether the classroom's fluorescent lighting has magnetic or electronic ballasts. Equipment Flicker Checker (from PowerSave Schools Tool Kit) Background Information Newer fluorescent light fixtures use electronic ballasts that are much more energy efficient than the older magnetic ones. They also have fewer problems for people who sensitive to fluorescent lights. Fluorescent fixtures with magnetic ballasts actually turn on and off 120 times per second. For many people (approximately 16 percent of the U.S. population) this cycling causes some level of discomfort, headaches or nausea. Electronic ballasts, which cycle thousands of times per second, do not have the same effects. Businesses that have converted from magnetic to electronic ballasts have seen dramatic decreases in sick days and increases in productivity. Stores that have converted have noted that sales increase because people feel more comfortable and spend more time in the store. They also benefit from the energy savings that come with electronic ballasts. Advance Preparation Prepare how you will handle the results. If it is discovered that the classroom lighting has magnetic ballasts, it is quite likely that some students will say that the lights have always bothered them. Be ready to respond to this situation. Leading the Investigation 1. Turn on the room's fluorescent lights. 2. Find a flat surface underneath the light that is to be tested. 3. Spin the Flicker Checker like a top on the flat surface. 4. Observe the top of the Flicker Checker. If a pattern is visible, the ballast is a magnetic. If the top of the Flicker Checker only looks like a blur (there is no discernable pattern), the ballast is electronic. Follow-Up If the lighting has magnetic ballasts, the class may lobby the administration to upgrade the school's lighting. They could cite studies showing that improved lighting in schools raised grades and test performance. Students find out more about the stroboscopic effect and whether it has other applications. Alliance to Save Energy s PowerSave Schools Program 30

31 Determining the Energy Cost of Exit Lights Objective Students calculate the energy and cost savings from changing incandescent light bulbs to LED bulbs in exit signs. Equipment Infrared thermometer* Set of Light Emitting Diode (LED) exit sign light bulbs* Step ladder Safety gloves* * From PowerSave Schools Tool Kit Advance Preparation Check to see which type of exit signs your school has. This investigation is designed for the older style exit signs that are lit by incandescent light bulbs. If your school's exit signs have already been upgraded to the newer fluorescent or LED bulbs, look for a nearby office building, store, or shop with the older signs. Explain the savings that could result from the investigation, and the owner may gladly let you test the exit signs. Find out from your utility or from the custodian what local electricity rate is per kilowatt hour (kwh). Find out from your custodian an estimated annual cost for replacing the exit light bulbs, including labor and material costs. Also find out the wattage and number of bulbs used in the exit light you will investigate. Safety Warning The exit light's incandescent bulbs will be very hot and can burn. Use safety gloves to remove them. Leading the Investigation 1. Discuss the importance of exit lights in terms of safety. Point out that the school would be subject to a fine if the Fire Marshall or Safety Inspector were to find an exit light not working. Have students calculate how many hours per year each exit light burns since it must be on 24 hours a day, 365 days a year (8760 hours). 2. Have students take a look at an exit light. Those with incandescent bulbs often have: Red plastic that has been warped or burned white by the hot bulbs. Broken filaments either from use (they may last as long as 6,000 hours or 7 months) or abuse (students sometimes slap at the lights, which breaks the bulb filament). 3. Follow the procedure described on the student page to compare the energy use of incandescent bulbs and LED bulbs in an exit sign. Alliance to Save Energy s PowerSave Schools Program 31