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Old 07-15-2008, 01:07 AM   #10 (permalink)
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1999 Saturn SW2 - '99 Saturn SW2 Wagon
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Mara -

Originally Posted by Mara View Post

It depends little bit how efficient your AC is... but with EER=10 rating 18000BTU unit consumes 1800W. At hot day expect little bit higher.
You got it, 9.7 EER.

My rough estimate is that the PV array STC rating should be about 1.5x of your AC load power consumption. If your location is not very hot, then maybe little less. You'll also need some battery bank to "ride through" some little clouds.
I'm not worried about battery backup because we (eventually) get the ocean breeze. If I can eliminate peak-load, I am a happy camper.

Before I started buying inverters etc... I was looking for DC operated air conditioners. Some are available for trucks, but none I found suitable for household use. (And the pricing was very expensive.) The benefit of DC operated unit is that there is no need for DC/AC inverter that eats about 10% of the power! Also the DC operated AC units claim to be very efficient according to this. You should get better than EER=15! (Don't know at what conditions they have tested...)
Hmmmm, the 2500 Watt/8525 BTU truck version is decent for a one-room summer "panic room".

Overall, I had a similar experience when I researched solar A/C. There were two products that I seriously looked at. I researched the SolCool Millenia :

SolCool - Solar Air Conditioners

Even though it would replace my 1.5 ton A/C, I can't justify $5K (not to mention it seems like it is never ready for public consumption).

Second, I have been tempted by the Solacool swamp cooler :

Solacool solar powered cooling

But, it's a higher maintenance proposition (evaporative pads), so I haven't been anxious to give it a try.

PS - Thanks to your thread, I think I Googled a website that sizes solar panels to categories of A/C usage (yet *another* option) :

Solar Powered Air Conditioning At Incredible Prices !


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