Trombe Walls
Introduction
A Trombe wall or Trombe-Michel wall is a wall or wall facing the sun, preferably to the north in the southern hemisphere and to the south in the northern hemisphere, built with materials that can accumulate heat under the effect of thermal mass (such as stone, concrete, adobe or water), combined with an air space, a sheet of glass and vents forming a solar thermal collector.
Edward Morse" patented the design in 1881 (US Patent 246626), but it was ignored until 1964. In the 1960s the design was popularized by constructions using the principles of passive solar houses in Font-Romeu-Odeillo-Via, France, by engineer Félix Trombe and architect Jacques Michel "Jacques Michel (architect)").
Operation
Its operation is based on the difference in density of hot air and cold air, which causes currents in one direction or another depending on which hatches are open. These currents of hot or temperate air heat or cool by introducing or extracting hot air from the building or rooms where it is installed.
Construction
It is a device that anyone can build with a minimum of construction knowledge. Although depending on the finish and the materials used, specifically the glass and insulators, it can give more or less good performance.
Operating diagrams
In these simple diagrams we can see how the currents of cold air (blue arrows) and hot air (red arrows) circulate, depending on the position of the trapdoors (yellow) on the wall of the building (orange).
The concept of the Trombe wall
During the day, the sun's rays pass through the glass sheet, heating the dark surface of the wall and storing the heat in the thermal mass of the wall. At night, heat escapes from the wall tending to cool mainly to the outside. But as it meets the glass sheet (it is semi-opaque to infrared radiation) the heat is delivered to the interior of the premises. Due to this, the average daily temperature of the wall is significantly higher than the average outside temperature. If the glazed surface is improved in its thermal insulation (through double or triple glass) the heat loss to the outside is much less, raising the temperature of the room to be heated. This allows that while there are low or very low temperatures outside, the interior of the premises is in hygrothermal comfort and properly designed and calculated, a constant temperature of 18 or 20 °C can be achieved inside the house.