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Cooling Alternatives

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sunnybouy60

Jan 1, 1970
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Hey guys, I was wondering what those of you that are off-grid use as an air
conditioner alternative? Swamp coolers? DC Fans? Are there any air
conditioners that run on anything other than AC?
 
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Blue Cat

Jan 1, 1970
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sunnybouy60 said:
Hey guys, I was wondering what those of you that are off-grid use as an air
conditioner alternative? Swamp coolers? DC Fans? Are there any air
conditioners that run on anything other than AC?
I use a solar PV powered DC fans for cooling during the early part of a
summer day, thus saving the amount of time I would need to run an air
conditioner.

As for air conditioners. I don't know of any that run on 12 VDC. The
component of an air conditioner, or an air conditioning system that uses the
most power is the compressor motor. I suppose you can find DC compressor
motors, but you will have to look.
 
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SJC

Jan 1, 1970
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sunnybouy60 said:
Hey guys, I was wondering what those of you that are off-grid use as an air
conditioner alternative? Swamp coolers? DC Fans? Are there any air
conditioners that run on anything other than AC?
One of the more cost effective devices I have seen is a solar powered
gable fan. It goes in the attic and vents out at the end of the house. This
keeps the attic cooler and the solar panel mounts right on the roof above
the gable, which cuts down on the wiring.
 
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Steve Spence

Jan 1, 1970
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sunnybouy60 said:
Hey guys, I was wondering what those of you that are off-grid use as an air
conditioner alternative?

ceiling fans and very little clothing. Of course 100f is a rarity around
here. if it gets too bad, it's road trip time in an a/c equipped
automobile to the beach (a bend in the local river). Mountain water
doesn't much above 70F even in summer.
 
E

Ecnerwal

Jan 1, 1970
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sunnybouy60 said:
Hey guys, I was wondering what those of you that are off-grid use as an air
conditioner alternative? Swamp coolers? DC Fans? Are there any air
conditioners that run on anything other than AC?

In these parts (NE USA), if you have sufficient panels to run the
winter, or even nearly run most of the winter, running an efficient air
conditioner in the summer is not likely to be a problem, at least on
sunny hot days...more sun, for more hours.
 
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sunnybouy60

Jan 1, 1970
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You know I have been to roadtrucker.com and have yet to find an AC unit.
 
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Gooey TARBALLS

Jan 1, 1970
0
That "http://www.zetatalk.com/shelter/tshlt15a.htm" was a great link - I
saved it.

There was a technique used or invented by the Romans a long time ago. A
natural form of air conditioning / ventilation was used roughly as follows:

1.. A trench 6 to 12 feet deep and 100 to 200 yards long was dug leading
from the "house" in a straight line away from the house.
2.. Into this trench a large diameter pipe (these days corrugated drainage
pipe 2 or 3 feet diameter) was laid, with holes drilled into the bottom to
drain water that condensed inside the pipe. The trench was then covered
over.
3.. At the far end a 90 degree elbow was attached and more pipe added so
that it reached above ground and the end covered with some sort of wire mesh
attached to keep out unwanted things such as rodents, etc., and then another
elbow could be added at this end to shield against rain.
4.. The house end of the pipe entered the house and was the source of
incoming air.
5.. The key to making this work is to add a convection chimney.
6.. The Convection chimney is built such that it's inside opening is at a
high point inside the building.
7.. On the outside, two intersecting sides of the chimney; are painted
flat black, and the resulting V formed by the two connecting sides face
south (these days , after the pole shift, they may need to face the new
south and be repainted). In other words, the V needs to face the mid point
between where the sun rises and sets.
8.. The two other sides must be transparent, Plexiglas or some equivalent.
Also, the higher/larger the chimney, the better.
How it works: the sun heats up the chimney causing the air inside to rise,
thus drawing air through the cool pipe. The pipe cools the air drawn from
the outside to the temperature of the earth at the depth at which it is
buried (which is virtually constant year around at this depth). By the way,
an interesting note: Even in cold climates where the ground is frozen, the
incoming air is only 32F when the air outside may be much colder, we need
only heat the air by 38F to bring it to 70F; as opposed to heating outside
air of say -15F to 70F we would have to heat the incoming air by 85F - quite
a difference in the amount of heating energy we would have to supply by some
other means.

Of course, without the sun to warm the chimney (or some other source) the
system isn't worth fooling with.

Offered by Ron.
 
Gooey TARBALLS said:
6.. The Convection chimney is built such that it's inside opening is at a
high point inside the building.
7.. On the outside, two intersecting sides of the chimney; are painted
flat black, and the resulting V formed by the two connecting sides face
south... In other words, the V needs to face the mid point between where
the sun rises and sets.
8.. The two other sides must be transparent, Plexiglas or some equivalent.

Transparent sides facing northeast and northwest, in the northern hemisphere?

Nick
 
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Gooey TARBALLS

Jan 1, 1970
0
Picky, picky, piky. The text said "In other words, the V needs to face the
mid point between where the sun rises and sets," and by implication
adjusting the facing direction of the transparent sides. And, I provided
the link: "http://www.zetatalk.com/shelter/tshlt15a.htm" to facilitate your
own research.
 
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greg mushial

Jan 1, 1970
0
Hey guys, I was wondering what those of you that are off-grid use as an air
conditioner alternative? Swamp coolers? DC Fans? Are there any air
conditioners that run on anything other than AC?

sunny -

We're not off the grid (yet)... but are moving that direction. In the
summer we have to deal with 30 days over 110degF, 70 days over 100: so
yes we need A/C. This summer will be our first test of doing w/o PG&E.
Our approach has been to use mother earth to absorb most of the heat,
and what we can't dump there we pump out with room size a/c units.
In terms of dumping the heat into mother earth - we have 300' (+/-)
of 4" ag drop link irragation pipes buried down 30"s. The hottest air
in the house gets pumped through them [heat transfer is proportionate
to temp difference, hence using the hotest air] and what we need over
and above that 500w a/c boxes take care of. (we use real a/c vs swamp
coolers in that we don't like the humid air they produce; neither do
the computers.)

Last summer I was still installing the heat-exchanger (what we call
the underground pipes) but still caught the september heat (114deg
max) and everything worked fine. We hope/expect this summer to
do the whole lot w/o PG&E. (currently at night we use the exchangers
in reverse, ie, the outside air is at freezing or just below, but we
keep the place at 52-53degF using the earth heat, and using wood
for the next 20 degrees. Previous years we've used 5-6 cords of wood
to keep the place warm - this winter (not over yet), in october we
had 5 cords in the shed (that's what it'll hold] and now mid-march we
still have 3+ left. The only problem we've noted is that if we don't
pump air through the exchangers they tend to have mold or ?? grow,
but by making sure that the fans stay on even if we're away for a
week, that problem seems resolved. [the house is a std 2800sqft 4/3
ranch.]

hope that helps,
greg
 
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