Solar Chimney

There are some ways to take the advantages of sustainable ventilation during design and construction phases of a dwelling rather than the operation and maintenance phase that are called passive ventilation. Although these passive designs were traditionally popular for ages, they have become the center of attention in modern constructions due to their affordability, simplicity, efficiency and being environmental friendly.  

Solar chimney provides natural ventilation by utilizing the solar energy to create different air pressure and consequently air convection. Just like in fireplace that the air and smoke from a fire will raise through a chimney, the low dense warm air tends to go out through the tunnel and generates air movement and brings cooling effect. This movement can be intensified by increasing the gap between the low and high existing temperatures of the building envelope. Therefore, it is reasonable to make the sunlight collector a good energy absorber by using dark colored thermal mass materials. 

To further maximize the cooling effect, we can integrate the solar chimney with a Trombe wall and force the air to go through underground ducts before it is allowed to enter the building. This system may be reversed during the cold season, providing solar heating instead.

Some advantages of implementing this system are:

• The system even works with diffused solar radiation.
• It can be implemented in windless areas and is not necessarily reliant on wind.
• The system is reliable and not liable to break down.
• The system does not need a large space and minimal exposure to exterior is sufficient.
• Cooling water is not necessarily needed in this system which is important in countries with major problems with drinking water.
• The needed building materials are sufficiently available everywhere.
• In very hot days the system still has a suitable ventilation effect.

This simple system can be designed and built in much larger scale (solar tower) in order to generate electricity out of the solar-thermal energy.