Method and apparatus for preheating ventilation air for a building

Abstract From the Canadian patent

Ventilation air for a building is preheated by providing on a south facing wall a sunlight-absorbent corrugated collector panel with the corrugations vertical, thus defining vertical channels between the panel and the wall, and vertical grooves on the exterior of the panel. Outside air passing upwardly along the channels is heated by a combination of solar heat from the panel and heat being lost from the interior of the building through the wall. Air passing upwardly along the grooves is heated by solar heat from the panel. The thus heated air is withdrawn from the channels and grooves and expelled into the interior of the building.