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A solar chimney or thermal chimney is a passive solar cooling and heating system that regulates temperature, improves ventilation, and enhances fire safety inside a house.
It uses environmental elements such as solar radiation, cool night breeze, and air pressure differences to adjust indoor temperatures.
A thermal chimney is a hollow vertical structure that connects the interior parts of the building to the outside. When the air inside the chimney heats up and its density decreases, it moves outside, leaving empty space inside. This allows the high-density, cooler air at the base to move into the solar chimney and eventually out of the building. As a result, the ventilation and subsequent cooling process occur.
The size of the thermal chimney is important for its effectiveness; the greater the size, the better. Ideally, a solar chimney should be placed on the south-facing wall if a house is built in the northern hemisphere.
A solar chimney should be carefully designed, and its construction material should be able to absorb the maximum possible heat to make sure that the thermal chimney performs satisfactorily.
The materials used for the construction of a solar chimney should be carefully selected because they affect the effectiveness of the structure.
Materials with high heat-absorbing capacity are desirable for the construction of thermal chimneys, example:
- Tinted glass
- Insulated glazing
How Does Solar Chimney Work?
When the air inside the thermal chimney heats up due to the sun’s heat, it moves out of the system. This brings the cooler air from below into the chimney, creating ventilation inside the building.
As shown in Figure-2, the cool air comes through the windows placed at a lower level of the house or an underground pipe system. The former is more economical and does not increase the total cost of construction.
The effectiveness of a solar chimney relies on its placement in the building structure. It should be placed at a location in the building that is naturally hit by the sun’s rays, especially the afternoon sun, which releases maximum heat energy.
The thermal chimney can be closed during the winter season to keep warm air inside the building and maintain a comfortable indoor temperature.
- Reduce energy costs by 50%
- Help saves lives in a building fire by increasing evacuation time
- Cheap to construct
- Low maintenance cost
- Ventilation can be controlled through an adjustable vent opening
A solar chimney is a solar heating and cooling technology that regulates temperature, improves ventilation, and enhances fire safety inside a house. It is a hollow container that connects the interior parts of the building with the outside.
When the air inside the thermal chimney heats up due to the sun’s heat, it moves up outside of the chimney. This pulls cooler air from below into the chimney. So, this process will create ventilation inside the building.
A solar chimney is effective in humid and hot climates. It should be tall and wide to increase the surface area that can absorb solar radiation and maximize surface area in contact with the air inside the chimney.
1. Tinted glass
2. Insulated glazing
1. Reduce energy costs by 50%
2. Help saves lives in a building fire by increasing evacuation time
3. Cheap to construct
4. Low maintenance cost
5. Ventilation can be controlled through an adjustable vent opening
How does passive solar cooling work?
How to provide shading for passive solar buildings?
What are design considerations for passive solar heating system?