Solar Energy Facts-The Trombe Wall

Trombe was the name of a French engineer who developed the Trombe wall, which forms a large solar thermal collector. A typical Trombe wall is 8 to 16 inches thick masonry faced with a double layer of glass which is placed a few inches from the wall to create a small airspace. The wall absorbs heat from sunlight passing through the glass. The heat is stored in the wall and conducted slowly inward through the masonry. In the northern hemisphere of course we want oiur wall to face south for access to direct sunlight. A dark surface on the side facing the sun facilitates heat absorption.

Solar energy facts show that the wall can be made of concrete, brick, rammed earth, or adobe. This is a technique that can be used for a new building or a solar retrofit. If it is designed right, this method of passive solar can cut down significantly on heating and cooling energy demands. The sun begins to heat the wall about midmorning, and continues to heat it all day. When the sun goes down the wall radiates its heat to the room inside. Rooms heated by a Trombe wall feel more comfortable because of the gentle infrared heat given off by the wall's surface.

Builders can use Trombe walls along with windows, eaves, and other design features, to achieve a balance of solar heating and cooling for a building's interior. Shading and vents to the outside can prevent the wall from gaining heat during the warmer months. A Trombe wall's performance is inhibited if the interior of the wall is not open to the room inside. For example, if shelves or cabinets are placed against the surface. Sometimes designers place projections on the inside wall to prevent bookshelves being placed against the wall. One of the things to remember when a Trombe wall is installed using adobe, rammed earth, concrete or other masonry, is that it may take a full heating season for the wall to dry out completely. The second season should show the true results.

Our solar energy facts lead us to the conclusion that a design including a Trombe wall is well worth consideration. This technique when combined with baseboard heating or even a small wood or gas stove is an excellent choice for new construction. A solar greenhouse including a Trombe wall is a viable option for a solar retrofit. Any good design will incorporate correct use of insulation. When I am ready to put up a new building, I will definitely include a Trombe wall as a part of the whole.