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Energy conversion

  1. Sep 20, 2010 #1
    Hi all,

    Dose kwh/m2 and mwh/cm2 and watt/m2 equal? if not what are the relationship between them?

    How can convert between them??

    Thanks in advance
    Smile_Face :)
  2. jcsd
  3. Sep 20, 2010 #2


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    Science Advisor

    kwh/m2 and mwh/cm2 are equivalent - they differ by some power of 10. In the numerator k=1000, m=1000000. In the denominator m = 100cm.

    watt/m2 is different in that the other two have time as a factor and this doesn't.
  4. Sep 20, 2010 #3
    Thanks for replying :)

    1 mwh/cm2 = 0.1 kwh/m2 is that right??
  5. Sep 20, 2010 #4
    incorrect. You are off by a factor of one hundred million.

    1 megawatt hour = 1,000,000 watt hours
    1 kilowatt hour = 1,000 watt hours

    1 meter = 100 centimeters


    1 megawatt hour per square centimeter = 1000 kilowatt hours per square centimeter.
    since there are 100 centimeters in a meter there are 10,000 square centimeters in a square meter.

    So 1000 kilowatt hours per square centimeter = 1,000 x 10,000 kilowatt hours per square meter = 10,000,000 kilowatt hours per square meter.

    I spelled everything out because I think you were confused by the abbreviations. You lost sight of what the units actually are.
  6. Sep 21, 2010 #5
    Be careful with upper/lowercase in prefixes:
    m = milli = 1E-3; M = Mega = 1E6
    p = pico = 1E-12; P = Peta = 1E15
    (and there´s deci and deka, of course)
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