One-dimensional analysis of compressible flow in solar chimney power plants

A novel theoretical approach for the calculation of the buoyancy driven air flow in all constitutive parts (entrance to collector, collector, turbines, collector-to-chimney transition section and chimney) of a solar chimney power plant is presented in the paper. It consists in the use of one-dimensional model of flow. The flow in the collector and the chimney is considered as compressible, while the flow in entrance to collector, turbines and collector-to-chimney transition section is treated as incompressible. Differential equations that describe the flow in the collector and in the chimney, together with algebraic equations that describe the flow in other parts of the plant are simultaneously solved. As a result, distribution of basic physical quantities, like velocity, temperature, pressure and density, in the collector and the chimney are obtained. The model is tested on two solar chimney power plants: well known Manzanares plant and Enviromission plant. The obtained results are in good agreement with measured results from Manzanares plant known in literature, together with predicted values of turbine power and turbine pressure drop for Enviromission plant. In addition, dimensional analysis of the model equations is performed and the results for mass flow rate, available turbine power, chimney height, etc. are presented. These results can be used as reliable prediction of the performance of solar chimney power plants.