This is an idea by my uncle actually. I am posting it for
him, as he isn't net savvy (yet).
The idea is to use the movement of hot air to keep the air
circulating. To achieve this he proposes the following
steps
Make a circular hole in the wall near the top of the room.
The hole should be
in the wall where the other side of it
is the outside of your house. (Quite obvious, but then a
mistake in that part could be a costly one). The size of
the hole depends on the size of the room, so cant say
exactly how big. You figure it out. The hole should be at
a slight angle, say 10 degrees, so that it is higher
outside than inside.
Take a metallic pipe of the same diameter (or just small,
we need to insert the pipe through the hole). Make it of
say 3 to 6 feet in length (again, just guessing, you be
the judge). The metal pipe should be one that conducts
heat very well. preferably the ones that are used for
cooking/ to make pipes in the solar heater, etc. Paint it
all black.
Now, we make a solar heat focuser. Google for "solar
death ray" and you will get the idea. You can make the
heat focuser out of anything. Mirror, shiny metal foils,
etc. The only difference here, is that this heat focuser
should be tubular. So that the metal pipe should be heated
from below, through all its length.
Now, we have a metallic pipe from the wall to the outside
of the house, at a slight angle, which is heated from the
below using solar heat. The air inside gets hot, and as a
result, will start rising. Pulling the air in the room
outside.
As an addition, a similar hole _could_ be kept at almost
the bottom of the wall, with a tank of water right next to
it. In theory, this will pull water vapor in and cool it.
I am somewhat skeptical about this one. But the main
concept above should work.
If you want the room to be kept warm, instead of cooling
it, you could probably reverse the angle of the pipe, thus
pushing the air in, instead of out.