Abstract

Objective

To investigate, and ultimately reduce, the amount of power that computer peripherals (like printers, monitors, and speakers) use.

Introduction

Saving energy in your home is a great idea for several reasons. First, a large percentage of the energy that most people currently use comes from burning fossil fuels. Fossil fuels are made from animals and plants that lived millions of years ago. Fossil fuels contain hydrogen and carbon, which are known as hydrocarbons. Most of the energy contained in fossil fuels comes from the combustion (burning) of their hydrogen. The carbon that is released as a result combines with the oxygen in the air to create carbon monoxide (abbreviated as CO) and carbon dioxide (CO₂). Carbon monoxide is a highly toxic gas. Carbon dioxide occurs naturally as we breathe in and out, but too much of it can be dangerous. Nitrogen oxides (NO_x) and sulfur oxides (SO_x) are also created by burning fossil fuels and are contributors to acid rain which can harm plants and aquatic animals. If we cut down on burning fossil fuels, we cut down on releasing chemicals that are dangerous for our health. In the year 2006, 35.9 percent of the world's energy came from petroleum, 27.4 percent of the world's energy came from coal, and 22.8 percent of the world's energy came from natural gas—all fossil fuels (EIA, USDOE). In 2007, burning coal created most of the electricity used in the United States.

While helping the environment is a great reason to save energy, another great reason to save energy is to save money. The amount of energy that you and your family use in your house is recorded by the power company. The power company charges your family for the number of kilowatt-hours (kWh) that your household consumes. Consumption is the amount of power used by an appliance or a whole house or apartment over time. The amount of electric energy that you consume is also known as power consumption. Power consumption is the product (think multiplication) of the power that you use, measured in kilowatts, and the total time in which you used that power, measured in hours. For instance, if you have a 100-watt (W) lightbulb in a lamp and you leave it on for 1 hour, the lamp has consumed 0.1 kWh. If you left the 100-W lightbulb on for 10 hours, it would consume 1 kWh. If you don't leave your lights on, then you don't use any kWh and the power company won't charge you for it. Saving a few dollars every month doesn't sound exciting, but at the end of the year, your family could end up with several hundreds of dollars. Who wouldn't like to have an extra few hundred dollars at the end of the year?

There are many things that affect power consumption in your home: the kinds of equipment that you have and how energy-efficient they are, how often and how long you use the equipment, and your own personal habits. For example, many people turn on their computers at the beginning of the day and leave them on all day, even if they are not using them. You can save energy if you turn on your computer only when you are using it and turn it off when you are not using it. But let's not forget the other computer-related equipment that you have, like printers, monitors, external speakers, WiFi hubs, and computer cameras. These pieces of equipment are called computer peripherals. Have you noticed that your printer has a light on it, even when you are not printing? When the light is on, the printer is consuming energy, even when it is not printing. Other equipment, like printer faxes, have clocks that never turn off, even when the equipment is off. That is wasted energy! These appliances are called vampire loads. In fact, about 5–10 percent of residential electricity use is due to vampire loads (LBNL, USDOE). Vampire loads (or vampire power) is responsible for roughly 1 percent of CO₂ emissions (LBNL, USDOE). You can learn more about vampire loads by watching this video from RealWorldGreen.com.

In this science project, you will find out how much energy your computer peripherals consume in one day and investigate a few different scenarios for each piece of equipment, such as using a power strip for your computer and its peripherals. You might be surprised to see which of the appliances that you choose are using energy, even when they appear to be off. Once you find out how much energy your household uses in a day, try making improvements to your power consumption. Put a permanent end to the vampires in your house!

Terms, Concepts, and Questions to Start Background Research

• Fossil fuel
• Acid rain
• Energy
• Kilowatt-hour
• Power consumption
• Efficient
• Peripheral
• Vampire load
• Cumulative

Questions

• What happens when there is too much CO₂ in the atmosphere?
• What is the difference between power and energy?
• What is standby mode? When would you put a computer or peripheral into standby mode?
• How much money is wasted in this country due to vampire loads?
• What does it mean when a piece of equipment or an appliance has the Energy Star designation?

Bibliography

• United States Energy Information Administration, Department of Energy. (2008). World Energy Overview: 1996-2006. Retrieved August 6, 2010, from http://www.eia.doe.gov/iea/overview.html
• Lawrence Berkeley National Laboratory, Department of Energy. (2010). Standby Power: FAQS. Retrieved August 11, 2010 from, http://standby.lbl.gov/standby.html
• Raphael, J. (2008, November 9). Unplug for Dollars: Stop 'Vampire Power' Waste. Retrieved December 6, 2010, from www.pcworld.com/article/153245/unplug_for_dollars_stop_vampire_power_waste.html
• American Council for an Energy-Efficient Economy. (2010, June). Home Electronics. Retrieved December 6, 2010, from www.aceee.org/consumer/home-electronics
• RealWorldGreen. (2008, April 21). Eliminate Vampire Power, Stop Wasting Electricity. Retrieved August 28, 2010, from www.youtube.com/watch?v=teefutIaNGQ&feature=related

Materials and Equipment

• An electricity usage monitor or meter, like the P3 International P4400 Kill-A-Watt Electricity Usage Monitor; available from www.amazon.com
• Computer and at least three peripherals
• Adult helper
• Power strip
• Lab notebook
• Graph paper

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Experimental Procedure

Important Notes Before You Begin:

• In this science project, you will examine the vampire loads of your computer peripherals. You will measure the load for each of four different conditions:
1. Plugged into the Kill-A-Watt meter and wall and turned on
2. Plugged into the Kill-A-Watt- meter and wall and turned off
3. Plugged into the Kill-A-Watt meter and wall and in standby mode
4. Plugged into the power strip, the Kill-A-Watt meter and wall and turned on
• Depending on the equipment that you have and the age of the equipment, it might or might not have the standby mode. It's ok if it doesn't, just remove that test condition.
• You will be testing each computer peripheral for 8 hours, three times each. Please be aware that during this time, you will not be able to use the computer peripheral for other purposes. You can use your computer if you move it to a different outlet.

Equipment Testing

1. Remove the Kill-A-Watt meter from its packaging and learn how to operate the meter. Read the included instructions completely. Note down in your lab notebook the maximum electrical ratings of the meter.
2. Make a list of the computer peripherals you will be investigating. Have an adult help you make sure that the electrical ratings of the equipment do not exceed the maximum electrical ratings of the Kill-A-Watt meter. The electrical ratings of an appliance tell you the maximum voltage and current that the appliance can handle without being damaged. You can find this out by looking at the back of the appliance or under the appliance for a metal plate with the values, or you can read through the appliance's instruction manual. Write the appliance's ratings in your lab notebook. Measuring equipment that exceeds the maximum electrical rating of the Kill-A-Watt meter can damage the meter.
3. In your list of computer peripherals, record which ones have the standby mode available.
4. There are several buttons on the Kill-A-Watt meter. The first button measures the voltage (in volts, V) that an appliance or piece of equipment is using, the second button measures the current (in amperes, A) that is being used, and the third button measures the amount of power (in watts, W) that the equipment is using. The fifth button, KWH/Hour, is a toggle button that displays the cumulative power consumption (in kWh) of the equipment that you have plugged into the Kill-A-Watt meter and the measurement time in hours.
5. Set up your peripheral for the first condition listed above. Turn off your computer and all of the computer peripherals. If these pieces of equipment are plugged into a power strip, turn off the power strip and unplug the power strip. Unplug all equipment from the power strip. Plug the Kill-A-Watt meter into the wall and then plug only the computer peripheral that you are testing into the Kill-A-Watt meter's outlet.
6. Turn on the first computer peripheral that you are testing. Note down the peripheral that you are working on in your lab notebook. Create a data table in your lab notebook, like the one below. Record the time that you turned on the equipment. This is the start time for the test.

7. Let the test go for 8 hours. The test mimics an 8-hour work day and allows for power consumption readings to accumulate to a readable value. After 8 hours, press the KWH/Hour button to take a power consumption reading. Make sure that you are reading power consumption (kWh), and not the time. Record the power consumption and the time that you stopped the test in the data table in your lab notebook.
8. Test the second condition in Table 1. Turn off the peripheral and keep it plugged into the Kill-A-Watt meter. Record the time you started the test in your lab notebook. This is the start time.
9. Repeat step 7 for this condition.
10. Now test for the third condition in Table 1. Turn on the peripheral, keep it plugged into the meter and the wall, and set it to standby mode. Note down when you set the piece of equipment to standby in your lab notebook. This will be the start time for the test.
1. If the equipment that you are working with doesn't offer this option, then just skip to step 12.
11. Repeat step 7 for this condition.
12. Test for the fourth condition in Table 1. Make sure the peripheral is turned off. Unplug it from the Kill-A-Watt meter and plug it into the power strip. Plug the power strip into the Kill-A-Watt. Turn on the power strip and turn on the equipment. Note down the time that you plugged the power strip into the Kill-A-Watt meter and turned everything on. This is the start time for the test.
13. Repeat step 7 for this condition.
14. Repeat steps 5–13 for each of the computer peripherals on your list.
15. Repeat steps 5–14 two more times for a total of three trials. It is always a good idea to repeat your experiments to make sure that your data is reproducible.

Analyzing Your Data

1. Review the data that you collected. Average the power consumption data for each computer peripheral and each test condition (unless your peripheral doesn't support the standby condition) over the three trials. Record the data in a table, like the one shown below.

2. Plot the data on a bar graph. Label the x-axis Test Mode and the y-axis Average Power Consumption. Choose a bar of a different color for each computer peripheral. You can plot all of the data on one plot.
3. Calculate how much money your household is wasting to vampire loads (standby mode and when the peripheral should be off) per month and per year for all of the peripherals you have. Assume 30 days per month. Review your electric bill to get the amount per kWh the utilities company is charging your family. What percentage of the electric bill is due to vampire loads?
4. Did the data surprise you? Is your household losing money to vampire loads? Which test condition proved to be the most wasteful?

Variations

• Broaden your inspection of vampire loads in your house. See if there are other appliances, like microwaves or television sets, in your house that are using power energy, even when they are off.
• Implement changes in your home to reduce vampire loads. Review your home's electric bill before making any changes, then review it again after making changes and see if it decreased.

• For more science project ideas in this area of science, see Computer Science Project Ideas.

Credits

Michelle Maranowski, PhD, Science Buddies

• Kill a Watt^TMis a registered trademark of P3 International.

Last edit date: 2010-11-10 12:00:00