trombe walls and thermal mass use
Trombe walls are intended to store heat during the sunny hours of the day and to release it into the house, at night, when temperatures are cold.
Trombe walls are typically concrete-masonry walls located in the sunny side of the house, with a sheet of metal foil glued on its surface and a single or double glass layer, next to the wall.
The goal
Trombe walls are part of natural heating strategies, and demand favorable climate conditions (sufficiently large number of sunny days with cold temperatures at night).
The goal of a trombe wall is to provide comfort and natural heating at night, while acting like a sponge during the day. Trombe walls use thermal mass principles. The image below, from EERE, shows how a trombe wall (at left) is located relatively to the winter and summer's sun, and how it combines with the home's overhangs.
Trombe walls use thermal mass principles. See: Thermal Mass Basics
Trombe walls and climate
Trombe walls can be successfully used in cold climates with sufficiently large periods of sunny time. Homes in temperate climates with cold nights, may also benefit from a trombe wall.
Trombe Wall Elements
Typical trombe walls involves 8 to 16 inch masonry walls, covered with a dark heat-absorbing material and a layer of glass placed at some distance (1 to 6 inches), to create a small airspace and maximize the yielding of heat.
The goal of this system is to generated and store the sun's heat (that passes through the glass and is absorbed by the dark surface in the wall) at a convenient rate.
Heat traveling rate
The trombe wall system is purposely conceived to conduct the heat slowly inward during at least 8 to 10 hours, before its releasing (heat will travel through the concrete wall at rate of about 1 inch per hour). The heat should only be released at a convenient time: a higher rate of conduction would release the heat too soon.
Sheet of metal, painting or Solar Panel
Trombe walls can be painted with a black-absorptive paint. That’s important to help to absorb the sun's heat.
To get higher absorption and better results, you may use a a sheet of metal foil glued to the outside surface of it. That metal foil sheet will absorb almost all the radiation and sun’s heat.
Some solutions use a solar thermal panel next to the trombe wall (instead of a sheet of metal foil), that may also be used to produce hot water. See the left-up image, from AZSolarCenter.
Trombe walls and overhangs
Trombe walls are used in conjunction with properly sized overhangs. The goal of the overhangs is, obviously, to shade the wall during the summer, when the sun is higher in the sky, preventing the masonry wall from heating the rooms in that period.
See: Overhangs basics
Comfort
Trombe walls can produce a very comfortable type of heating (similar to the highly prized radiant floor heating): the heat stored in the wall is diffused by radiation, which is more comfortable than heating with common heaters...
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