Passive Solar Heating
A transpired solar collector can be as simple as allowing sunlight into a heated space through south facing windows. The heat energy is then stored in the building materials inside the space. Passive solar collectors use the natural convective movement of heated air to transfer heat from the solar collector into the building. When the sunlight is sufficiently intense, the air between the clear glazing and the dark metal absorber is warmed and rises. This hot air exits into the building through a slot at the top of the wall into the building. A slot near the bottom of the wall allows cool building air into the solar collector to start its cycle again.
Active Solar Heating
Active solar air heating systems use fans to draw in, circulate, and exhaust air. The perforated cladding system is a bare plate solar collector that use fans to draw air through thousands of tiny holes in a layer of unglazed dark metal plating which acts as the solar absorber. Replacing cladding on a wall, the absorber, when exposed to direct sunlight, transfers heat to the air as it passes into the building.