An air mass flow
has a temperature increase
when heated with solar radiation
according to the formula
is the soil absorption factor,
is the glass transmittance factor,
is the density of air, and
is the specific heat of air .
The air mass flow as the result of a temperature difference in a stack of height
and cross section
can be calculated by
is the discharge coefficient for the opening (assumed to be 0.65) .
Solving the above two equations simultaneously gives the temperature between the end of the collector and the entrance of the stack where the turbine is located.
The resulting power of the turbine can be calculated with the formula
For comparison, the solar radiation energy on the same surface area as the canopy roof is
The following quantities are calculated in the Demonstration:
: the mass flow of air in the stack
: the air speed in the stack
: the power generated in the turbine
: the solar radiation energy on a surface equal to the collector roof surface.
The theoretical background of a solar updraft tower is discussed in . Most of the formulas used here come from this article.
Other interesting descriptions are found in .
For a theoretical background of the stack effect see .
A working solar tower in Spain is discussed in .
For solar tower projects around the world see .
 J. Schlaich, R. Bergermann, W. Schiel, and G. Weinrebe. "Design of Commercial Solar Updraft Tower Systems." 1000 Friends of Florida. www .1000friendsofflorida.org