At our school we make sure to keep nice big windows in the trombe wall, so the room is bright enough.
Also I don't like the traditional trombe walls, that are sealed, and you have to operate vent holes in the top and bottom every day. Instead, at our school we keep the trombe wall about 6 nches (15 cm) away fromt he glass, and we don't seal it. That way we can reach inside to pull a curtain or clean the glass. I like that much better. Then we don't have to operate vent holes, which people always forget. For the coldest part of winter we can operate a curtain between the glass and the wall.
Ralf Siepmann wrote:Hi Folks,
yesterday I watched a longer Youtube video about earthen plasters. The guy managed to darken his clay plaster by mixing in finely ground coals left over from his wood stove. Looked good, dark but not pitch black.
This could also be applied to tromb wall plaster.