Image Credit: EnviroMission
Today I would like to introduce you to what is known as a natural draft solar tower (not to be confused with a concentrated solar tower). This is a technology that will generate electricity using the power of the sun. The working principle behind this is actually pretty simple, and it has to do with how the density of air varies with temperature.
As we all know, hot air rises. The reason it rises is because it’s density is lower than that of cooler air. This solar tower utilizes the motion of the hot air rising in order to spin turbines – which create electricity. In the image above, you see a big circle with a stack coming out of the middle. The big circle is actually made up of glass panels, and the circumference of this circle is open to the atmosphere. When the sunlight hits the air beneath the glass panels and heats it up, the air wants to rise due to it’s relatively lower density. Since the glass panels confine the upward motion of the air, it is forced to go through the stack in the middle of circle. In this stack, there are a number of turbines which will spin when the hot air rushes through them in order to rise. At the same time, more air is drawing through the circumference of the circle of glass panels.
Image Credit: geek.com