|Solar Wind Tower Illustration|
Solar towers or chimneys as some call them are low-tech. The power conversion rate is much lower than other solar thermal designs, such as the solar collectors now operating in California and other areas. However, low cost per solar collector area helps offset the low conversion rate.
The solar collectors in California and elsewhere have drawn some criticism. I wrote about Brightsource Energy and its Ivanpah solar thermal power plant in the Mojave Desert in the February 21, 2014 post “The Spaniards are Coming.” Besides the water requirement to keep solar collectors clean, critics are concerned about heat rising out of the structure as well as the land requirement. Solar wind towers deserve the same scrutiny. However, the conclusions might be different.
The real concern for Solar Wind Energy’s design is the water requirement. Pumps deliver water to an injection system at the top of the tower so that a mist can be blown across the tower opening. The water evaporates into air heated by solar rays. The air becomes cooler, denser and heavier than the outside warmer air, and falls through the cylinder at speeds up to and in excess of 50 miles per hour. The company is silent on the amount of water required to operate its solar wind tower, so this is where things get murky for Solar Wind Energy’s environmental reputation.