Trombe wall
Solar collector with double glazing on a wall that faces south; it is used to distribute heat in a room.
air gap 
Space between the wall and the glazing in which air flows; as air heats up on contact with the wall, it rises naturally in this space.
concrete wall 
Masonry structure that is about 15 in thick; it has a black surface to absorb heat from the Sun to heat the air.
cold air 
Fresh air enters the home at the base of the air gap and is heated on contact with the wall.
absorbing surface 
Black wall that catches solar radiation and converts it into heat.
double glazing 
Each of two glass plates placed in front of the concrete wall; they allow solar radiation to penetrate and retain the heat.
warm air 
Air heated by solar radiation is introduced into the room by convection.
shutter 
Flap gate used to control the entry of heat into the home.
solar radiation 
All the electromagnetic waves emitted by the Sun.