# Energy conversion

1. Sep 20, 2010

### Smile_Face

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??

Smile_Face :)

2. Sep 20, 2010

### mathman

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.

3. Sep 20, 2010

### Smile_Face

1 mwh/cm2 = 0.1 kwh/m2 is that right??

4. Sep 20, 2010

### mrspeedybob

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

So

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.

5. Sep 21, 2010

### maimonides

Be careful with upper/lowercase in prefixes:
m = milli = 1E-3; M = Mega = 1E6
p = pico = 1E-12; P = Peta = 1E15
(and thereÂ´s deci and deka, of course)