motivation - [principle] - technology - energy production costs

The solar updraft tower basically operates like a hydroelectric power plant, but instead of water it uses hot air (Fig. 2).

Beneath a large glass roof air is heated. It enters a vertical tube placed at the center of the roof and creates an updraught there. Inside the tube Kaplan-type wind turbines with electrical generators are producing electricity. Contrary to the power plants with reflecting mirrors, the glass roof collector of a solar updraft tower also operates with overcast sky, resp. diffuse light - a decisive advantage!

Fig. 2: Principle of the solar updraft tower: glass roof collector, chimney tube, wind turbines.

Continuous 24 hours-operation is guaranteed by placing tight water-filled tubes under the roof. The water heats up during the daytime and emits its heat at night. These tubes are filled only once, no further water is needed (Fig. 3 and 4).

Day:

Night:

Fig. 3: Principle of heat storage underneath the roof using water-filled black tubes.

Fig. 4: Electricity output during 24 h as a function of the thickness of the water layer.