A Trombe wall is a massive Equator-facing wall that contains a dark color (or ideally masonry product) covering that will absorb thermal energy from sunlight and is covered over with a non-uv panel on the outside and insulating air-gap between the wall and the glaze, creating a cavity for the air to be trapped. This is not our unique idea, but a Trombe wall is a passive solar building design strategy that adopts the concept of indirect-gain, where sunlight first strikes a solar energy collection surface which covers thermal mass located between two surfaces. The sunlight absorbed by the surface is converted to thermal energy (heat) and then transferred into the living space via wall vents. We had our duct guys create a boot that was the depth of our wall that would accept a traditional 4″ x 24″ register vent on each side of our wall during the mechanical rough-in. In the Summer months, the vents in the glazing will remain open and hot air will escape via chimney effect.
Taking a look at the photos, and the illustration arrow pattern, you can start to get a sense of how this works and how the air travels passively into the home. If you are struggling to see how this can create heat inside the home, think of how hot it gets inside your car in the summer time with the windows rolled up. As soon as the windows are open, the hot air moves to the cooler space.
I’ve recently made a visit to this project on a very cold January day and the heat gain was outstanding. It was almost too hot to touch the interior vents. During construction, we used a mercury thermometer that would read out temperature of 140 degrees and they quickly maxed out. I will say this particular feature of our project had some doubters, but they have since become believers.