GUIDE TO SCHOOL SMALL AUDIT FOR TEACHERS & STUDENTS By Clare Pries April 2008 Coolmob trading as Environment Centre Northern Territory, April 2008
SMALL AUDIT Nearly all small appliances use stand-by power, there are some exceptions such as most toasters, electric kettles, blenders, but generally if an appliance is turned on at the power point it will be consuming energy, even when it is not turned on at the appliance switch. Compared to the amount of power it requires when it is operating this energy requirement is small, however because the amount of time it is in stand-by it is not uncommon for an appliance to use more energy while waiting to be used than actually in use. For example a video cassette recorder which is used for 2hrs per day and requires 14 Watts of power to operate will consume 14W x 2 hrs = 28Wh = 0.028kWh of electricity. If this appliance has a stand-by power of around 3 Watts then over the remaining 22hrs in the day the appliance will use 3W x 22hrs = 66Wh = 0.066kWh, almost 2 ½ times more than when running. When you consider that out of the 8760 hrs per year, students are in class for only around 1340 hrs, and, that there are hundreds of small appliances at schools, there can be considerable opportunity to reduce the amount of energy they use. In addition, these systems generate heat, which in turn increases the load on the air-conditioning systems. COMPUTER SYSTEMS Turn off computers, printers, scanners, and modems at the power point when not in use. Ask your IT staff which computer servers at your school could be turned off on weekends and school holidays. Table 1 lists typical power used by components of computer systems when idle, in stand-by, and/or when turned off at appliance switch. $ IDLE STAND-BY POWER Desk Top Computer 110-7 Monitor 50 5 1 Hard-Drive 60-4 Speakers 3 3 2 Laptop Computer 20-3 Printers (small) Scanners 8 8 3 10 10 1 Modems Servers 6 6 2 40-120 - - Table 1 1 SCREEN SAVERS DON T SAVE ENERGY! Configure the energy saving features on computers. When idle a desk-top computer will consume around 110W (depending on the graphics, using screen savers can use more), just under half of this power requirement is for the screen. Most computer systems can be set up to automatically turn off the screen after a period of inactivity. Follow the steps below to set up the power options on your computers. Step 1 Select Control Panel Step 2 Select Power Options Step 3 Select power scheme or manually select time-out options 1 The energy consumption figures used within the tables have been sourced from: L. Harrington, P. Kleverlaan, April 2001, Quantification of Residential Standby Power Consumption in Australia: Results of Recent Survey Work, National Appliance & Equipment Energy Efficiency Committee, available at http://www.energyrating.gov.au; COOLmob Appliance Energy Use and Greenhouse Impact Infosheet, available at http://coolmob.org; and, Sustainable Solutions Pty Ltd, 2003, A Study of Office Equipment Operational Energy Use Issues Final Report, available at http://www.energyrating.gov.au.
If these features are not available on your systems, implement a monitor switch off policy in which users switch off monitors when not using for more than 5 minutes. Consider getting students and teachers into the habit of switching off computers when they finish using them in the hope the habit will be continued at home. STEREOS, MICROWAVE OVENS, PROJECTORS, DISHWASHERS, BATTERY & PHONE CHARGERS, TV S, VCR S, DVD PLAYERS Turn off these appliances at the power point when not in use. Table 2 lists typical stand-by and/or power off for these appliances. $ STAND-BY POWER Portable Stereo 10 2 Microwave Oven 4 - Dishwasher 2 2 Phone Charger 1 - Battery Charger 1 - TV 10 0.2 VCR 8 5 DVD 10 1 Projectors 14 4 Table 2 7 PHOTOCOPIERS, LARGE PRINTERS AND FAX MACHINES Photocopiers and large printers can use 200W to 1300W when operating, when idle the power consumption of these machines can still be 20W to 200W depending on the model. Activate power save mode on photocopiers (if warm-up times are low), and turn off at the power point at the end of each day. If fax machines are not required overnight turn off at power point. Table 3 lists typical idle, stand-by and/or power off for these appliances. $ IDLE POWER SAVE/STAND-BY Fax Machines 8 8 0.5 Large Photocopiers 80 1* - 80 0* - 70 Large Printers 30 30 0 5 *Low power save, stand-by, and off power requirements are features of Energy Star compliant photocopiers. Energy Star is an international standard for energy efficient electronic equipment. Table 3 7 PA SYSTEMS Turn off school public address system at the end of each day. An idle PA system consumes around 40W for the main control components, plus 100W to 300W for the speakers installed throughout the school. If the timers associated with recess and lunch bells require resetting each time system is turned off talk to your IT contractor about reconfiguring system for you. $ SPLIT-SYSTEM AIR CONDITIONERS Split-system air conditioners can use anywhere from 1W to 15W 2 of power in stand-by mode. Some of these systems are powered from a power point and can easily be turned off manually when not required, most however are hard-wired or have difficult to access on/off switches, these units should be turned off through the appropriate circuit breaker in the electrical distribution board when not required for extended periods. $ SEVEN DAY TIMERS Where people may not often remember to turn equipment off after hours, or for hard to reach power points consider using a seven day timer. Times can be set for each day of the week and can be easily over-ridden if needed to be used during after hours periods. A copy of the after 2 Based on limited survey through COOLmob home energy audits. Generally older models will consume more than newer models.
hours use instructions should be displayed near the timer to maintain correct operation. If appliance is not required over school holidays turn off seven-day timers at the power point. Note a seven day timer will consume around 10kWh per year, make sure the savings achieved by reduced appliance operation and stand-by times is greater than this. $ Copies of the override instructions above are available to download at: www.nt.gov.au/infrastructure/bss/everyone/resources.shtml Seven day time switches may be available for NT Government schools from the Infrastructure Sustainability Unit. STUDENT ACTIVITIES 1. Undertake small appliance stand-by audit of your classroom. (Example shown below) TYPE & HOW MANY IN CLASSROOM SURVEY QUESTIONS ARE POWER SAVER OPTIONS ACTIVATED? NO COMPUTERS 1 X LAPTOP 5 X DESK TOP ARE COMPUTERS TURNED AT RECESS? NO - AT LUNCH? NO - AT END OF DAY? YES - AT START OF SCHOOL HOLIDAYS? YES ARE SCREEN SAVER GRAPHICS USED? YES ESTIMATE NUMBER OF HOURS PER SCHOOL DAY COMPUTERS ARE: LEFT IDLING (SCREEN ON) WHEN NOT IN USE 4HRS LEFT IDLING (SCREEN ) WHEN NOT IN USE 0 HRS LEFT ON AT POWER POINT WHEN TURNED AT SWITCH 16HRS PRINTERS TV (CRT, LCD, or PLASMA) 1 X SMALL 1 X CRT ARE THESE S USUALLY LEFT ON AT SWITCH WHEN NOT IN USE? USUALLY LEFT ON AT POWER POINT WHEN TURNED AT SWITCH? VCR & DVD 1 X VCR MICROWAVE 1 USUALLY TURNED AT POWER POINT WHEN NOT IN USE? PRINTER, STEREO, AND VCR USUALLY LEFT ON AT SWITCH WHEN NOT IN USE DURING SCHOOL DAY, AT SWITCH OVER-NIGHT AND ON WEEK ENDS, AT POWER POINT DURING ALL SCHOOL HOLIDAYS PORTABLE STEREO 1 TV IS TURNED AT POWER POINT WHEN NOT IN USE MICROWAVE IS NEVER TURNED
2. Discuss how your classroom could reduce the energy used by your small appliances by changing the way you currently operate them. Estimate the annual energy and green house gas savings you could achieve using the section on Estimating Energy consumption & Potential savings. 3. Whilst stand-by power accounts for around 2% of a schools electrical energy use it can account for over 10% of a home electrical energy bill 3. Discuss the opportunities to reduce stand-by power consumption at home. Students could undertake a stand-by power audit of their homes. 4. Undertake stand-by power audit of school and assess where energy savings can be made. 5. Determine the number of seven-day timers you require at your school and contact the Infrastructure Sustainability Unit to request some for your school. 3 L. Harrington, P. Kleverlaan, April 2001, Quantification of Residential Standby Power Consumption in Australia: Results of Recent Survey Work, National Appliance & Equipment Energy Efficiency Committee, available at http://www.energyrating.gov.au