Calculating power consumption

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messiahmessiah
Posted:
in Genius Bar edited January 2014
How do I calculate how much it costs to run the following for a year?:



30" Cinema Display (standby mode 12hrs of the day)

23" Cinema Display (standby mode 24hrs of the day)

Power Mac G5 Quad (running in 'Reduced' mode 24/7)

17" PowerBook (connected to the mains 24/7)



The only spec I could find concerning power consumption was for the Cinema Displays (150W for the 30"). But how does this relate to KWh, is the 150W figure per second, per hour or what?

Comments

  • Reply 1 of 8
    theapplegeniustheapplegenius Posts: 584member
    I think the Quad sucks down 500-600W, if not more.



    Edit: This should help you a bit. http://www.amug.org/amug-web/html/am...articles/quad/

    A 1KW power supply in that beast. Wow.
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  • Reply 2 of 8
    messiahmessiah Posts: 1,689member
    Quote:

    Originally posted by theapplegenius

    I think the Quad sucks down 500-600W, if not more.



    Edit: This should help you a bit. http://www.amug.org/amug-web/html/am...articles/quad/

    A 1KW power supply in that beast. Wow.



    Holly Cow!



    24kWh per day?



    8,760kWh per year?



    Anybody want to buy a Quad?
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  • Reply 3 of 8
    mr. hmr. h Posts: 4,870member
    Quote:

    Originally posted by Messiah

    How do I calculate how much it costs to run the following for a year?:



    with difficulty



    Quote:

    Originally posted by Messiah

    30" Cinema Display (standby mode 12hrs of the day)

    23" Cinema Display (standby mode 24hrs of the day)

    Power Mac G5 Quad (running in 'Reduced' mode 24/7)

    17" PowerBook (connected to the mains 24/7)



    The displays wouldn't be too hard. You should be able to use the power consumption figures quoted, if you can find numbers for On (at the level of brightness that you use) and Standby (are you saying you never use the 23"? I assume it's a typo, because having a display and then keeping it on standby 24 hrs a day seems excessive )



    The computer is harder to work out, as the power draw can vary substantially depending on what you are doing with it.



    Quote:

    Originally posted by Messiah

    The only spec I could find concerning power consumption was for the Cinema Displays (150W for the 30"). But how does this relate to KWh, is the 150W figure per second, per hour or what?



    Watts are a measure of how much energy is being used per second. One Watt is one Joule of energy being used each second.



    The kWh is therefore a measure of energy. It is one kW * one hour, therefore 1 kJ (kilo-joule) * 3600 (number of seconds in an hour) = 3600 kJ



    Therefore, if you leave a 150 W device on for one hour, you've used 0.15 kWh of electricity (because there are 0.15 kW in 150 W, and you ran it for an hour).



    learn more here



    Quote:

    Originally posted by Messiah

    Holly Cow!



    24kWh per day?



    8,760kWh per year?



    Anybody want to buy a Quad?



    The PSU being a "1 kW" PSU does not mean that it always uses 1 kW of power. It means that it is capable of delivering 1 kW of power output if necessary. Apple have to provide a PSU that can supply the power required if you pack the G5 with all the PCI-E cards and HDDs that you possibly can. If you have a look at the AMUG article that has been linked to already, you'll see that in the tests they ran, the maximum power draw of their Quad was 339 Watts.
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  • Reply 4 of 8
    bentonbenton Posts: 161member
    Messiah:

    Maybe this link to a power meter will be helpful.

    http://www.amazon.com/gp/product/B00...lance&n=228013
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  • Reply 5 of 8
    messiahmessiah Posts: 1,689member
    Many thanks for all the replies guys!
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  • Reply 6 of 8
    thinkingdifferentthinkingdifferent Posts: 1,604member
    Quote:

    [i]Originally posted by Mr. H



    The computer is harder to work out, as the power draw can vary substantially depending on what you are doing with it.





    Cheat, measure current draw with an Amp meter and multiply by voltage. P=IV, right..
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  • Reply 7 of 8
    mr. hmr. h Posts: 4,870member
    Quote:

    Originally posted by ThinkingDifferent

    Cheat, measure current draw with an Amp meter and multiply by voltage. P=IV, right..



    Almost.



    If you're dealing with D.C. the equation is simple to apply. With A.C., it gets a little more complicated because there is reactive power, real power and observed power.



    I imagine that a P.S.U. as beefy as the PowerMac G5's has power-factor correction , which will make the reactive power negligible, so that you can apply the P=Irms*Vrms rule. But, a device that can measure mains current draw can almost certainly measure mains power usage directly anyway.



    If you really want to know how much power your computer is using, definitely the best thing to do is buy a power meter.
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  • Reply 8 of 8
    ebbyebby Posts: 3,110member
    I had this same problem and was fearing I was going to trip a fuse.



    I bought a Furman PM-8 series II power conditioner and have all my gadgets channeled through this one device.

    IMAGE

    As you can see, it has a voltage and current meters (in Amps). Simply multiply the two numbers to get watts. At any time my G5 station is running roughly 600-1000 watts.



    They should have these displays as a screensaver! They are hypnotizing to watch.
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