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Old 01-12-2015, 17:15   #16
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Re: Power for airconditioning??

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Originally Posted by StuM View Post
200 Amps is about 8000 BTU (assuming a nominal 12V system). If that's enough cooling power, then OK, but it's not a lot.
Stu, I think you made mistake of directly converting electrical power to cooling power. In other words:
200 A x 12 v = 2400 W gen output
2400 W x 3.412 BTUH/W = 8200 BTU/hr (incorrect for cooling)

But an air conditioning cycle uses electrical power to move heat and the cooling capacity in W is greater than the energy input required in W. This is cooling coefficient of performance (COP) and usually ranges between 2 and 4. In USA AC units are rated in SEER which is BTU per Wh ratio of cooling to electrical energy.

If assuming a SEER value of 12 or COP of 3.5 you get (for the 200 A supply):

2400 W elec input x 3.5 COP = 8400 W cooling
8400 W x 3.412 BTUH/W = 29,000 BTU/hr cooling

Of course any generator would need to handle the high inrush current demand of the compressor unit starting, which is usually a limiting factor.
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Old 01-12-2015, 19:16   #17
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Re: Power for airconditioning??

Doh,

All three of you are correct. Mea Culpa! I was totally forgetting about COP/EER (actually EER in this case).
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Old 01-12-2015, 23:43   #18
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Re: Power for airconditioning??

sorry all///I was just trying to get some general info on the issue...
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Old 01-12-2015, 23:55   #19
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Re: Power for airconditioning??

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sorry all///I was just trying to get some general info on the issue...
No problem glad to help ya
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Old 02-12-2015, 01:50   #20
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Re: Power for airconditioning??

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sorry all///I was just trying to get some general info on the issue...
What are you apologising for? It was a legitimate question.

And the subsequent discussions managed to make me look like an idiot and that doesn't happen often.
I occasionally need that to stop me getting big headed.
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