One of the many things a home is meant to provide, other than shelter, is warmth. There are many things that can be implemented to ensure temperature stabilisation including passive solar design and thermal mass. However, sometimes, even a stabilised temperate home may need some extra heat. So, how do you supply extra heat in a sustainable, ecological and resource free way?
Enter the Trombe wall.
Designed to absorb solar energy during the day and releases it selectively as convective heat to the interior during the evening, it is a great form of “central heating” that doesn’t require the use of additional resources. Basically, a wall designed to absorb and retain heat, it is often designed as a small alcove containing an air space and separated from the outdoors by a form of glazing. In colder climates, the alcove is larger and contains additional heat absorbtion items such as dark volcanic rocks or steel barrels filled with water. In temperate or tropical environments, a smaller alcove with a black painted wall is more than sufficient.
Connecting this air space with the inner room are two vents, one at the top and one at the bottom of the trombe wall’s air space. As the Sun shines through the day, the UV and infrared waves heat the solid wall behind it and the trapped air is heated. As heat rises, the vents allows a convection vacuum to form, pulling in cold air from the vent below and pushing hot air into the room from the vent above. The real trick with this though, is that for sometime after the sun goes down the now hot wall will still keep heating air and exchanging that heat into the room which is why colder regions tend to fill this void with additional heat absorbing materials.
During summer, if the roof overhang is deep enough, the higher Summer sun will be unable to heat the glass. With an opened vent to the outside put at the top of the outer side of the air space and by closing the inner top wall vent in Summer, you create a Solar Chimney that sucks air out of your house to the outside, giving you a cooling ventilation as well.
Simple heating and cooling without the use of resources.