# Solar AC?



## hunterseeker (Aug 4, 2012)

Nit exactly a homesteading question, but definitely dealt with electricity. If it's in the wrong place, please move it.

I've been considering some kind of cooling unit for a camper top on the back of my truck. I want to use the bed for well, a bed, but since it has been so hot lately, I have been making other arrangements. So I was thinking about a solar cell and deep cycle batteries to power it but was curious if anyone had an idea on a cooling unit to knock the heat back. I know it takes a lot of power for one to cycle on and don't know if a solar power system can handle it. Any ideas?


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## hunterseeker (Aug 4, 2012)

Keep in mind this entire system needs to be mobile.


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## BillS (May 30, 2011)

An air conditioner would require a thousand times the power of a small solar cell and battery system. One talked about on this site would use 1200W of power. That's equal to 12-100 watt light bulbs:

http://www.overstock.com/guides/common-questions-about-window-air-conditioners

According to this site you would need 1,000 square feet of solar panels to power a 1200W air conditioner:

http://answers.yahoo.com/question/index?qid=20080409072650AAQY5O6


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## hiwall (Jun 15, 2012)

If you are in a dry climate you could maybe use a RV swamp cooler. Even just a fan uses alot of power


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## Davarm (Oct 22, 2011)

You could look into Peltier Cooling devices. Take less juice than a traditioal AC.

http://www.eicsolutions.com/peltier-cooling-devices.php


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## hunterseeker (Aug 4, 2012)

Gee! That would be mobile. Hmm. Back to the drawing board. 

The main thing I'm after is a way to cool that camper without running the truck. Guess I'll just have to wait a few months and let nature do it.


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## hunterseeker (Aug 4, 2012)

Davarm said:


> You could look into Peltier Cooling devices. Take less juice than a traditioal AC.
> 
> http://www.eicsolutions.com/peltier-cooling-devices.php


Now we're talking. I knew there had to be something out there. This is definitely a start in the right direction. Now implantation....


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## hunterseeker (Aug 4, 2012)

Looks like solar is not the option here but I am curious about charging the batteries through the vehicles alternator now. Hmmmm...


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## hiwall (Jun 15, 2012)

Actually the Peltier 2500 btu uses about twice the power as a 5000 btu window ac. Both 120 volt. I can not see any advantage and certainly not power savings. But an interesting cooling system.


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## LincTex (Apr 1, 2011)

Correct... Peltiers are pretty power hungry.

Not portable... But I think in a good day's work I could rig up an old water pumping windmill to turn an old A/C compressor from a car. Possible, but still a lot of work to plumb it, charge the freon, etc.


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## Davarm (Oct 22, 2011)

Their is one advantage to the Peltier cooling devices, the dont have the high current draw at start-up like the conventional ac(compressor) units do.

Not saying that the Peltier is the way for someone on solar to go but if a choice beween the two "HAD" to be made, it is one advantage. Personally, I think that a shady spot on the river bank would be more practical but I was tossing out an option.


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## hiwall (Jun 15, 2012)

Thanks Davarm, I had never heard of them before. I did a bunch of research after you told us about them. And you are corect that is why people plant shade trees


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## CrackbottomLouis (May 20, 2012)

LincTex said:


> Correct... Peltiers are pretty power hungry.
> 
> Not portable... But I think in a good day's work I could rig up an old water pumping windmill to turn an old A/C compressor from a car. Possible, but still a lot of work to plumb it, charge the freon, etc.


If you had a small windmill attached to an alternator it seems logical to turn it flat and the wind while driving would charge the battery. When stationary if it was mounted correctly you could just raise the bar it was attached to and have it spin in the wind. Ive never done anything remotely like this just what popped into my head qhen reading. I still think a back up system would be necessary as ac takes a lot of power as I understand it.


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## kejmack (May 17, 2011)

If you live in an area that has lower humidity, you can use a swamp cooler. It is much more efficient than AC.


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## eddy_dvyvan (May 8, 2012)

There is no efficiant way of having a/c.

Either do it natural with laying out near a river under a tree 


or....
Buy a truck above cab a/c unit second hand. Configure something like a thermo fan's on/off switch like the davies craig units and put it in the sleeper.

Instead of hooking the switch/sender upto a thermo just hook it into the ignition.

Temp sender read on temp.........carstarts with a/c(manual dials ect) already set to go....

Temp sender reads off temp.......car switches back off.

1-2 hours later it does it again.

Dont forget a master switch to bypass it

Not an ideal option i know


But a/c is a luxury.......


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## LincTex (Apr 1, 2011)

Dig a deep root cellar... it will be the coolest place in the hot summer.


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## Marcus (May 13, 2012)

You might also consider an AC unit like those that are made for travel trailers. Seems I recall some work off of propane.


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## Conelrad (Sep 2, 2009)

A lithium bromide absorption system would work essentially from solar energy alone, but the size necessary to get it to run efficiently would make it impractical for a mobile application.

To wit: 300' lineal feet of reflector solar collector, a large converter unit (about the size of a big refrigerator, $10K), and a chilled water air handler. This will yield about 40 tons of refrigeration, and need about 1800 Watts of electrical power to tun a couple small pumps and a fan.

Really efficient, very low maintenance, no toxic or environmentally sensitive refrigerant, but costly.

http://www.sakura-aircon.com/News/Sakura_Developed_Mini_Solar_Absorption_Chiller.html

http://www.yazakienergy.com/waterfired.htm

DG


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## LincTex (Apr 1, 2011)

A really big Icy Ball?

http://en.wikipedia.org/wiki/Icy_Ball


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## hunterseeker (Aug 4, 2012)

Portable vs. cost effective does not equal feasible. I wish a riverbank was an option but in this case it's not. I can't even find a shade tree where I need it. At least it will be cooling down naturally soon.

Going to leave the air conditioning to greater minds. One day, somewhere......


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## Offgridgiles117 (Sep 18, 2012)

Depending upon your location Solar to drive your A/C would be feasible. Just use the Solar to charge a battery bank and size the bank to drive your AC.

Limit the number of hours per day it runs to minimize the reserve.

Of course the size of the NEEDED unit matters as well.

You can also consider Mini-split systems which use minimal electricity in their low settings and still keep things cool. Good insulation as well...

It is totally feasible with solar. Just depends up on how much you want to spend....


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## LincTex (Apr 1, 2011)

Offgridgiles117 said:


> It is totally feasible with solar. Just depends up on how much you want to spend....


Yeah but he wants portable, too - and that many batteries are not portable, unless you pull your travel trailer with a Freightliner.


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