Lesson 3: Lighting. Light Bulb Debate

Transcription

1 Lesson 3: Lighting Light Bulb Debate In 2007, President George W. Bush signed into law the Energy Independence and Security Act, which focused on reducing energy consumption and greenhouse gas emissions. Part of this legislation requires light bulbs to be 25% more efficient by To achieve this goal, inefficient incandescent light bulbs will be gradually phased out, beginning with a ban on manufacturing and importing 100 watt incandescent bulbs planned to take effect in January, By 2014, most incandescent bulbs are scheduled to be banned, except for some specialty bulbs that are exempt from the law. As a result, consumers will be required to purchase higher efficiency compact fluorescent lights (CFL) or light emitting diode (LED) lamps when they need replacement bulbs. Today you ll be watching a segment from the NBC Nightly News about the light bulb ban. Listen to the arguments that people are making in the video, and list at least three of them in each column below. As the debate is happening, take notes on the opposite side. For: Why do you think the ban is a good idea? Against: Why do you think the ban is a bad idea?

2 Using the arguments you heard in the video and in your class discussion, fill in information on the diagram that organizes the effects of the light bulb ban (both good and bad) into each of the Three Spheres: People, Planet, and Profit. Circle all of the positive effects and underline all of the negative effects.

3 Lighting: Comparing Bulbs Have you ever noticed how hot incandescent bulbs can get? So hot, in fact, that for years they ve been used to hatch chicken eggs and bake cookies in Easy Bake Ovens. Research indicates that up to 99% of the energy an incandescent bulb uses is transformed into heat. Compact fluorescent lights (CFL) and light emitting diode (LED) manufactures claim that their bulbs are much more efficient because they produce the same amount of light while using less energy and generating less heat. Directions : Use the following procedure to test this claim and compare the energy inputs and outputs of three equivalent household light bulbs. Part 1. Measure Energy Input 1.Record the wattage that is printed on the bulb itself. 2.Use a watt meter to determine the actual Measured Wattage, and record in table 1. Part 2. Measure Heat Output 1.Record in table 2 the room temperature before you turn any of the bulbs on. 2.Arrange each thermometer 3 inches away from each lit bulb. 3.Record in table 2 the temperature at each listed time interval. 4.Calculate Ambient Heat Generated by subtracting the Room Temperature from the Temperature After 7 Minutes, and record in table 2. Table 1. Energy input of three equivalent household light bulbs Bulb Type Listed Wattage (watts) Measured Wattage (watts) Light emitting diode (LED) Compact fluorescent (CFL) Incandescent Table 2. Energy output of three equivalent household light bulbs Bulb Type Room Temp ( ) After 3 min ( ) After 5 min ( ) After 7 min ( ) Ambient Heat Generated ( ) LED CFL Incandescent

4 Lighting: Life Cycle Cost Many energy efficiency upgrades cost more money up front than the products that they replace, but claim to save you money on energy costs in the future. How can we evaluate these savings? For any potential efficiency upgrade, a good way to compare the price of different technologies is to calculate their Life Cycle Cost, which factors together the price of the product itself, its projected life span, and how much energy it will consume in the future. Compact fluorescent lights (CFL) and light emitting diodes (LED) cost more per bulb than incandescent light bulbs, but offer greater energy efficiency and longer life spans. Which will ultimately save you the most money? Use the data below to find out how much each technology costs in the long run. We will use a common 25,000 hour life span about seven years with the light on 10 hours a day to compare each bulb. Use the following information in your calculations (updated as of 2015). Incandescent Bulb Compact fluorescent (CFL) Bulb Light emitting diode (LED) Bulb Light Output : 860 lumens Energy Used : 60 watts Life Span : 1,000 hours Cost Per Bulb : $2.42 Light Output : 900 lumens Energy Used : 14 watts Life Span : 10,000 hours Cost Per Bulb : $1.49 Light Output: 800 lumens Energy Used : 9.5 watts Life Span : 25,000 hours Cost Per Bulb : $ Calculate the Total Cost of Materials (A) for 25,000 hours of light: (use the cost per bulb from above) Incandescent CFL LED # Bulbs needed for 25,000 hours of light x Cost per bulb = Total Cost of Materials (A) 2. Calculate the Total Watt Hours (B) used when producing 25,000 hours of light: Incandescent CFL LED # Hours in each bulb lifespan x Wattage for each bulb x # needed for 25,000 hours of light

5 = Total Watt Hours (B) 3. Find the Total Operating Cost (C) of producing 25,000 hours of light: (use your answer for B in the first box) # Total Watt Hours (B) x Price of electricity per watt hour $ $ $ = Total Operating Cost (C) 4. Calculate the Total Life Cycle Cost of each bulb type when producing 25,000 hours of light: (add A + C from above) Cost of Materials (A) + Total Operating Cost (C) = Total Life Cycle Cost Incandescent CFL LED 5. Now, use your Total Watt Hours (B) data to determine the environmental impact of each bulb, in terms of how much carbon dioxide (CO2) gas emissions each type of bulb would release when producing 25,000 hours of light: Total Watt Hours (B) Incandescent CFL LED x Pounds (lbs) of CO 2 released per watt hour lbs lbs lbs = Total CO 2 emissions (lbs) Answer the following discussion questions in complete sentences. 1. Using your life cycle cost calculations, which bulb technology would you recommend in this scenario? Why? 2. This life cycle cost calculation was made for a lighting fixture with high usage (70 hours a week). Would your recommendation change if the light fixture had a very low usage, such as two hours a week? Why or why not?

6 3. Over a 25,000 hour life cycle, how many pounds (lbs) of CO2 can you keep out of the atmosphere by switching from an incandescent to a CFL bulb? 4.Over a 25,000 hour life cycle, how many pounds (lbs) of CO2 can you keep out of the atmosphere by switching to LEDs? Read the following using your annotations. Clean Energy Analyst: Lighting The Challenge At home, at work, and at school lighting plays an important role in our comfort, safety, and productivity. According to the U.S. Department of Energy, lighting also accounts for about 15% of Americans home energy bills. Fortunately, increasing the efficiency of lighting systems is one of the easiest, most cost effective ways to make a building more sustainable. The challenge of the energy analyst is to identify lighting options that are the most cost sensible and energy efficient without sacrificing the quantity or quality of light needed for a particular space. To do so, they must first determine the intended function of the lights in a room; for example, does the customer need bright focused light for an effective workspace, or soft ambient light for a relaxing environment? After lighting needs are assessed, analysts can calculate the potential savings and payback time to conclude the best retrofit. The Solution When evaluating lighting energy consumption, energy analysts look mainly for opportunities to: 1) upgrade inefficient lights, 2) install lighting controls, and

7 3) reduce or modify existing lighting systems to make the best use of available lights. There are three major types of lighting, known by energy analysts as lamps, that are used in indoor applications: incandescent, fluorescent, and light emitting diode (LED). The most common fluorescent lamps are tube fixtures (often found in schools and office buildings) and compact fluorescent lamps (CFLs), which fit into standard sockets and are ideal for domestic use. Fluorescent tube lamps are available in different diameters, and analysts often recommend upgrading to smaller tubes, which deliver a comparable quantity of light while using less wattage to do so. In most cases, energy analysts recommend that all incandescent lamps are replaced with more efficient CFL or LED lamps. LEDs are the most efficient, but are currently also the most expensive, so analysts must perform a cost benefit analysis to determine which lamps are most appropriate for their application. Controls for lighting systems ensure that lights are on only when they are needed, and can be created by installing electronic sensors or timers, or by simply promoting behavioral changes (such as turning off the lights whenever you leave a room) that maximize efficiency. In areas where lights are prone to be left unnecessarily, energy analysts recommend installing low cost motion, infrared, or sonic sensors that activate lights only when a room is occupied. For buildings that are only in use part time, analysts can recommend installing timers on the lighting system to ensure that no lights are left on when the building is empty. Sometimes, lighting can be reduced or removed while maintaining the same level of functionality. Where small tasks are regularly performed such as doing homework at a desk the whole room does not need to be lit, only the workspace does. Energy analysts call this task lighting. In rooms where sunlight is plentiful, analysts also recommend using natural light whenever it is available, also known as daylighting. Finally, energy analysts can improve lighting efficiency simply by recommending regular cleaning and maintenance of light fixtures. Clean fixtures allow lights to achieve their maximum brightness.

8 Lighting: Reduce, Upgrade, Control, and Maintain Energy conservation measures (ECMs) for lighting can be classified by the acronym RUCM: Reduce, Upgrade, Control, and Maintain. Using what you know about the strategies of a Clean Energy Analysts, write your recommended ECMs in the chart below. RUCM: Lighting Reduce: How can we reduce the energy we use for lighting? Upgrade: How can we upgrade existing lighting systems to make them more efficient? Control: How can we control the energy we use for lighting? Maintain: How can maintenance strategies improve lighting efficiency?

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