We are constantly reminded by the media of the vital role we can play in the drive to use energy more efficiently by switching off non-essential equipment not in use. At schools we often see that the workstations in the computer laboratories are kept on during the night causing it to go into “sleep mode” until the next morning when it is interacted with for the first time. The question to ask is whether switching off the workstations at the end of a day will have any significant effect on the school's energy consumption.
It is estimated that an average computer uses about 186 Watt of energy per hour while it is in use (110 Watt for the CPU and 76 Watt for a CRT monitor) and about 145 Watt of energy while not in use (sleep mode)
Scenario: School X uses their Khanya laboratory on average 6 hours per day. The workstations are kept on at the end of the school day, but are only turned off during weekends and holidays. The workstations will go into sleep mode when not used and will wake up in the mornings when it is first interacted with.
We can calculate the energy usage of school X on a monthly basis as follows:
Daily usage while in use (6 hours) = 27 900 Watt (25 x 186 Watt x 6)
Daily usage while not in use (18 hours) = 65 250 Watt (25 x 145 Watt x 18)
Total weekly energy usage for school X = 465 750 Watt
Monthly energy usage for school X = 1 863 000 Watt = 1863 kW
Total monthly cost @ R0.2945 per kW = R 548.65
From the scenario above it is clear that more energy and money is spent on the equipment while it is not is use. School X will be able to save 1 305 000 Watt of energy (which equates to R 384.32) a month by simply turning off the workstations in their computer laboratory at the end of the school day.
Is the above enough reason to switch off the workstations at the end of the day?
Monday, March 17, 2008
Saving energy
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4 comments:
It is good enough a reason to switch off workstations when not in use.Sometimes small measures matter big.Any amount of power we save these days,however negligible it may look,will make a huge difference on the national grid.
The obligation now lies on us as Facilitators to spread the word,the figures are there to prove the effectiveness of powering off our workstations when not in use.
Does anyone have a handy tool whereby one could calculate the electricity usage per ICT item and then translate that to Rands and cents?
Some stickers on each appliance and a spreadsheet will do. Usually there are power and/or voltage and/or current ratings on the appliance itself. A simple spreadsheet with Denric's formulas will do the trick.
Alternatively use the Data Harvest device/TRAC equipment for a few days to log the current and voltage data per device per day. Furthermore, calculations can be done as suggested in this blog. Give this task to a science student - Grade 11 or 12
Accurately measuring a computers power usage is not a simple task, since the usage depends on a few factors, eg. the size of the hard drive, what kind of memory is being used, video card type, etc. I am busy with a spreadsheet where all these factors will be taken into account and will assist you with acuurately measuring the power usage of your computer.
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