EnergySmarts: Part 1 Tara Smith and Sandy Cardon, BSU "When I use Energy"

Transcription

1 Time Frame: Sections A and B: Two full (50-minute) class periods, separated by 10 days Section C: Two 50-minute class periods (can be performed in the timeframe above) Objectives: EnergySmarts: Part 1 Tara Smith and Sandy Cardon, BSU Standards: Common Core Standards for 4 th - High School The Reading and Writing standards are attached as a word document labeled Language Standards. The Math standards are attached as a word document labeled math standards. Students will be able to investigate the variables used in energy consumption. Students will create a clear writing example of their home energy use. Students will gather data from their home electric utility meter. Students will use data available from the local utility. Students will view and interpret a scatter plot provided from the local utility Students will plot multiple profiles of data using a scatter plot. Students will sort data Students will perform calculations such as average, median, mode, standard deviation, percent difference Students will compare graphs Students will begin to understand the overall effect of using electricity Background Information: Intermediate Energy Infobook. The NEED Project Electricity Section: pages Law of the conservation of energy: Energy cannot be created or destroyed it is converted from one form to another. We don t seem to notice how dependent we are on electricity until there is a power outage. The utility has no control over when we turn on light switch, when our hot water heater kicks on, when we make coffee or when we do anything else in our homes that consume electricity. The power that our electronic devices consume has to come from somewhere and it is the utility s job to make sure they can supply our irregular demand. Even an act as simple and, seemingly insignificant, as turning on a light switch is making a power plant somewhere work just a little bit harder. The effect can be compounded significantly when many people start using a lot of electricity at the same time (i.e. a very hot afternoon and everyone is running their A/C at the same time). What is the difference between power and energy? Power is the rate at which work is performed and is measured in Watts (W) or kilowatts (kw). A kw is equal to 1000W

2 Energy is the power (kw) used over a certain time period (hours, h) and can be measured in kwh. o For example, if a device uses 1kW (Power) for 1h (time) it consumes 1kWh of energy o Electricity is billed by the kwh What do typical electronic devices consume? o A 100W incandescent light bulb left on for one hour consumes 1kWh of energy o A 1500W hair dryer used for 6 minutes uses 0.15kWh o Have your students research other devices such as TVs, computers, hot water heaters, ovens/stovetops, etc.! o Kill-a-Watt TM meters display how much power an electronic device consumes. They are available for check-out from most public libraries or may be purchased for less than $20. Materials: Computer with internet connection Home Energy Use Example Data (Excel file) An online account with your local electric utility. The student may need a copy of his/her bill to set-up an account. Procedure: The activities below may be mixed, matched and altered, as needed. Section A: Energy Icebreaker Icebreaker Activity: Power Haus (we are here to pump. you up) Start off with a brainstorm on a large sheet of paper answering the question "What powers your house?" (When you turn on a light switch where does the energy come from?) Answers might be... Power Plant, Electricity, Coal, Natural Gas, Wind, Fossil Fuels...etc. Start a separate sheet with three headings across the top of the page and number them: 1 Low 2 Medium 3 High And brainstorm the following question: What devices in your home consume electricity and what category would you place them in for energy consumption? For example, a light would be "low" and an air conditioning unit would be "high". Divide the students into four groups. Each group will represent one haus and will use various amounts of energy. We will call the one that uses the most energy High Energy, the one that uses the least energy Low Energy, and the ones in between Variables. All four of these houses get their energy from one power plant. We will have one person be that power plant. The power plant will take the first brainstorm paper and attach it to - 2 -

3 themselves (we recommend using string like a sign hung around the neck). Set up the groups in this manner... Give each household five minutes to brainstorm what they think will be a "typical" energy usage for their home during any time frame (i.e. turning on lights, computers, TVs, A/C, etc.). To demonstrate how irregularly most homes use energy, encourage the variable homes to use a lot of energy some of the time and very little energy at another time. The teams will then take turns telling the power plant about what electricity they are consuming and the power plant will have to do jumping jacks (i.e. perform work) to power the home. Low energy items will be worth one jumping jack, medium energy tasks will be worth two jumping jacks and high energy tasks will be worth three jumping jacks. Once each team has had a turn, announce that it is 5:00pm and everybody is home cooking, and watching TV, with all of the lights on, and it is a hot afternoon so the A/C is on... Have every group tell the power plan what it needs at the same time over a lapse of 1 minute and see what the power plant does. The power plant will be doing jumping jacks as fast as it can, but not be able to keep up. The goal of this ice-breaker is for the student to understand that 1. a power plant has to work a little harder in order to generate even the small amount of power to turn on a light 2. seemingly small amounts of electricity usage are compounded when a lot of people are consuming it at the same time 3. the utility has to have power available to the consumer at all times, even though it has no control over when the consumers use energy Section B: When do I use energy? An online account with the local electric utility is required. If the family has not already set up an account, the student may do so (with parental permission) on the company s website. The student should only need a copy of their family s utility bill to set up an online account. 1. Keep a journal of your home's energy usage for one week. Record the time and duration (if applicable) of activities such as, but not limited to: a. When family members wake up, take showers, cook, make coffee, do laundry, vacuum, use the computer, watch TV, leave for work/school, turn the heat (if electric)/ac down or up, heat (if electric)/ac usage (do not record every time AC turns off and on, just record general observations like if it is a cool day and the AC isn't on much or if it is a hot day and the AC runs all afternoon), etc. b. At the end of each day, draw a scatter plot (time on the x-axis and energy usage on the y-axis) of what you think your energy usage looks like for that day. c. Consider the following questions: - 3 -

4 i. Which day do you think your family used the most energy? The least energy? Why? ii. What time of day do you think your family is using the most energy? The least energy? Why? iii. What are some things you think your family could do differently to lower it's energy consumption? iv. Other observations/issues? 2. Three days after you complete your diary, log on to your electric utility s account manager. View your "Daily and Hourly Energy Use" for each day corresponding to your journal entries. Answer the following questions: a. How much energy did your family use this week? Each day? b. Which did your family use the most energy? The least energy? How does this compare to your hypothesis? c. What time of day did your family use the most energy? The least energy? How does this compare with your hypothesis? d. Is your family's high usage times consistent by day? What factors affect this (i.e. perhaps the family sleeps in on the weekend so the morning "energy buzz" occurs at 9AM instead of 7AM)? e. What is your family's energy usage at night? Does this seem high or low? Is this surprising to you? What could be using energy at night? f. Does any of this data seem surprising to you (i.e. an energy spike in the middle of the day when everyone is at work/school or at night when everyone is sleeping)? g. How does your energy diary and your online energy usage data compare? Are there any discrepancies (i.e. a peak in the data that does not correspond to recorded activity)? Why might that be? 3. Based on the online data and your energy diary, what do you think are the three devices that use the most energy in your home (i.e. AC? refrigerator? coffee maker?)? a. After answering this question, have your students research the devices that typically use the most energy. The top three "energy hogs" usually are: 1.) heat (if electric)/ac (may not see this if activity performed during spring/fall when not using heat/ac), 2.) hot water heater, and 3.) clothes dryer 4. Using the data obtained, perform the following calculations (use the price per kwh on your bill): a. percent difference in energy use between a "high" use time (i.e. evening) and a "low" use time (i.e. middle of the night) b. percent difference between a weekend day and a week day c. how much your family spent on energy this week. d. how much your family spent on energy each day e. how much your family spent on energy for one night (11pm-7am), day (7am-3pm) and evening (3pm-11pm) i. average, mean, median, modes for energy used and money spent - 4 -

5 Section C: Exploring example home energy use 1. Calculate the average energy usage of each home for the entire timeframe, for the cooling months (July/August), neutral months (September/October) and heating months (November/December). Calculate also mean, median, mode and standard deviation for each home. a. Do the averages seem high/low/what you would expect? Why? b. How do the averages, mean, median, modes and standard deviations compare between houses (i.e. which one uses the most energy? the least energy?)? Why? 2. Insert a column between House #4 and Temperature. Label it "Total Energy" and give it the units "kwh". Create a data series in this column that is the total energy used by all four houses. This is an example of what the utility sees and is required to manage... the total amount of energy being used simultaneously by all homes in its service area. 3. Choose one day from each cooling category above and graph all four homes and the total energy as an overlay scatter plot with time on the X-axis and energy on the y-axis. Each home and the total energy will be represented on the same plot as a different "series" (five total). Not all four homes have data available on all days so make sure the dates chosen have data for all four homes. For example, Home #1 does not have data available on 7/1/09 so this day should not be chosen. a. How does the energy use vary during the day? b. What might each family be doing during the plotted days to affect the energy usage? For example, a spike at 7AM might indicate the family has just woken up, the lights are on, and people are showering and making breakfast. c. How do the days you have plotted for each month compare to each other? How do the days compare between teams? Why might this be? d. How does the energy usage of each home compare with the total? How much more drastic are demand peaks when compounded over four homes? How might the utility balance this? 4. Choose two days within a given month and plot both days for one house with time on the x-axis and energy on the y-axis (this overlay plot now has two days for one house rather than one day for multiple houses). a. How do the two days within the same month compare? b. Why might they be different? For example, is it a day that falls on Monday through Friday or a Saturday and Sunday? Is it ever possible to have two days with the exact same energy usage? 5. Repeat section 3 and 4 but overlay the temperature (time on x-axis and temperature as a secondary y-axis). 6. Plot temperature (x-axis) vs. energy usage (y-axis) for all four homes. a. How does the temperature affect the total energy usage? The energy usage of each home? (section 3) b. Does the temperature data seem to affect the varying amounts of energy used between two days in the same month (section 4)? - 5 -

6 c. What do the plots in section 5 and 6 demonstrate? Do they show the same information? Which plot presents the data more clearly? Why? 7. Select the entire data set for your home. Sort the data from largest to smallest kwh and plot on a scatter graph. (To sort, highlight the entire dataset for one home. Click data at the top of the screen, then sort. Select the kwh column and largest to smallest or descending order. Click ok ) The resulting plot, known as a load duration curve shows the amount of time over the six month data window that your house uses varying amounts of energy. On the left hand side, it shows how your home uses a great deal of energy for only a small fraction of the time. The same is true on the right hand side of the plot, where the data shows that your home uses very little energy for a small fraction of the time. The broad middle section of the plot shows how much energy your home uses the majority of the time. a. How much energy does your home seem to use most of the time? How does this compare with the average you calculated in Step 1? b. How do the four homes compare? c. How significant or insignificant do the max/min energy usage portions seem? d. Imagine you have 1,000 homes or 10,000 homes or 100,000 homes. How does this affect the significance of the max/min energy usage? What impact does this have on the utility providing power? Assessment: Journal: Ensure that energy usage has been completed in sufficient detail for each day. Did the student include time and duration and a variety of activities for each family member? Did the student form hypotheses based on their observations? Did they use complete sentences? Could someone unfamiliar with the activity read and understand their journal? Was the student able to create a reasonable graph corresponding to their observations (i.e. low energy usage at night and when people aren't at home and high energy usage when they are at home)? Is the graph properly labeled (title and axes) and does it show numbers and units? Was the student able to identify ways his/her family could reduce energy usage? Online data: Was the student able to successfully set up an online account? Was the student able to locate and view the online data? Was the student able to interpret and correlate the online data with their journal entries? Was the student able to identify the energy use high/low days/times? Was the student able to reasonably explain discrepancies between the journal and the online data? - 6 -

7 Was the student able to use their journal and the online data to make reasonable estimates of the top three energy hogs? The student does not need to have the right answer here, but should be able to logically connect their observations with the data to form a conclusion. Calculations: Did the student show his/her work? Units? Correct number of decimal places? Did they show a logical and reasonable thought process, even if answer is incorrect? Did they cancel units correctly? Excel Data/Graphing: Was the student able to create the required scatter graph? Were the axes correctly labeled? Did the chart have a title? Was the student able to overlay plot the data? Was the student able to correctly identify differences between the graphed data (i.e. which house consumes more) and key elements in each graph (i.e. max and min)? Did the student actively participate in the activity and discussion? Did the student answer all questions? Even if the answers were incorrect, was the student able to reasonably support his/her answers? Was the student able to sort the data? Does the student understand that every type of electricity consumption has to be powered by an electricity source? Additional Content: 1. Students can read their electric meter various times throughout the day for several days, record and plot the data and compare to the data available online. Please refer to the Energy Consumption lesson plan ( 2. Additional SmartMeter activities are available in the NEED SmartMeter lesson plan ( 3. Generate a bell curve with the Excel data 4. Have the student plot the entire 6 months of data (sorted by time, not kwh like in step 4). Why does it look so scattered and messy? What does it tell us? References: Idaho Power SmartMeter Account Manager ( Intermediate Energy Infobook. The NEED Project Electricity Section: pages