Solar Chimneys- Another Viable Energy Source

After reading Alex's last post I was reminded of a physics project from high school in which the goal was to design a "Cool House", or a house that could stay cooled in the summer months and warm during the winter without the use of air conditioning or heating.  I remembered something called a solar chimney that my group included in our presentation as a means of natural air conditioning so I did a quick google search to refresh my memory as to exactly how it worked only to discover that a solar chimney isn't what i thought it was at all.  Even though I was mistaken as to what a solar chimney was, my google search was not useless.  I discovered that solar chimneys are used as a fairly cheap way to generate energy using plain, old air.  I will attempt to describe how they work even though it is described better and in more detail in the video posted below.  An area of land is covered in special plastic but with room underneath for air.  This air is heated by the sun, and follows a basic rule of air, when heated it rises.  There is a chimney with turbines which serves as the only way out for the air.  When the air is forced to escape through the chimney it turns the turbines, creating energy.  The cost to build a solar chimney is relatively cheap and air and sunshine don't cost thing, making this method of energy harnessing extremely viable and eco-friendly.