I’m experimenting with a transparent heat transfer wall.
It would be a transparent wall attached to the outer south wall, leaving about one inch between them. The out wall would be painted a dark color. Ideally it would be black but that would be too much of an eye sore. So dark brown would be fine. This way it would attract maximum heat from the sun.

The sun would pass through the transparent outer wall and hit the dark inner wall and get hot. The air trapped within the two walls would heat up and rise, pulling more air from below that would in turn heat up.

During the winter we could have an air passage from that area into the house where the hot air could pass. Because of the pressure of rising hot air it would naturally get pushed into the house. This technology works since I’ve seen similar set ups.

I have thought of another use for the same system but have yet to run it by engineers to see if my physics is right. In the summer the passage to the house would be closed and another one going outside would be opened. This means, if my theory is correct, that the hot air would pass up and back out into the outside, thus pulling heat from the house into the atmosphere.

This seems to be a good natural heating and cooling system using the thermodynamics of simple rising hot air and the sun. The wall could easilly be made out of glass or Plexiglas.