Solar wall

Figure 1. A building with a solar wall. The solar wall is the black, perforated wall on the right side of the image.

Solar walls are a technology used to passively heat a building. Similar to Trombe walls or solar chimneys, solar walls are one way to achieve energy efficient building design. These walls combine exterior construction with interior devices to use solar energy to heat and ventilate indoor spaces. These walls can be installed on new buildings or can be retrofitted onto old ones.

The solar wall is constructed first by placing metal solar cladding on the exterior wall of a building. This cladding is perforated and built in front of an already present wall. In the Northern hemisphere, this wall is south facing. Collector panels are then installed to create an air channel, allowing for the exchange of warmed air between the two walls.

There are several benefits to using this technology. Outside of the cost of operating the HVAC system, the heat from the Sun does not require the burning of fuel like many heaters and boilers do. This reduces the associated carbon dioxide emissions of heating a building. Solar walls can even keep a building warmer in the winter as the added solar wall shields the actual exterior wall of the building from cold air. These walls are also fairly inexpensive because of their simplistic construction, approximately equal in cost to the installation of a brick wall.

How They Work

Figure 2. House with solar wall, Centre for Alternative Technology.

The perforated cladding on the outside of the building is heated by the solar radiation from the Sun. Because of this, solar walls are generally very dark or black. This reduces the amount of radiation that is reflected from this wall. The system must be hooked up to the building's HVAC system, as ventilation fans are used to create negative pressure in the air channel between the walls. This negative pressure pulls air warmed by the Sun into the building. Cool air is expelled from inside the building into the air channel through a vent located at the bottom of the wall. Once this air is warmed, it begins to rise and is then fed into the HVAC system through a vent located at the top of the wall. The warm air is supplied to and distributed in the building via the HVAC system intakes.

For Further Reading

For further information please see the related pages below:

• Thermal insulation
• Home heating
• Convection
• Building envelope
• Air infiltration and exfiltration
• Or explore a random page