A Trombe wall is a sun-facing wall built from material that can act as a thermal mass such as stone, concrete, adobe or water tanks combined with an air space, insulated glazing and vents to form a large solar thermal collector.

During the day sunlight shines through the glazing and hits the surface of the thermal mass, warming it by absorption. The air between the glazing and the thermal mass warms (via conduction) and rises, taking heat with it (convection). The warmer air moves through vents at the top of the wall and into the living area while cool air from the living area enters at vents near the bottom of the wall.

At night a one way flap on the bottom vent prevents backflow which could act to cool the living area and heat stored in the thermal mass radiates into the living area.

Common modifications to the Trombe wall include:

• exhaust vent near the top that is opened to vent to the outside during the summer.
• Windows in the trombe wall. This lowers the efficiency but may be done for natural lighting or aesthetic reasons. If the outer glazing has high ultraviolet transmitance and the window in the trombe wall is normal glass this allows efficient use of the ultraviolet light for heating while protecting people and furnishings from ultraviolet radiation when compared to using windows with high ultraviolet transmitance.
• Electric blowers controlled by thermostats.
• Fixed or movable shades.
• Trellises
• Insulating covering used at night on the glazing surface.
• Tubes, pipes or water tanks as part of a solar hot water system.
• Fish tanks as thermal mass.
• Using a selective surface to increase the absorption of solar radiation by the thermal mass.

It is an example of passive solar heating, and is named after the French inventor Felix Trombe .

External links

• Trombe Walls http://www.nrel.gov/documents/trombe_wall.html