Mathematical Modelling of the Performance of a Solar Chimney Power Plant with Divergent Chimneys

Chimney is a critical component influencing the performance of a Solar Chimney Power Plant (SCPP). An enhancement on the power output of SCPPs with divergent chimneys was observed in a number of experimental and numerical studies using Computational Fluid Dynamic (CFD) models. In this paper, a mathematical model was established to analyse the hydrodynamic features of a series of divergent chimneys in a SCPP. The importance of estimating the loss from the potential diffuser stall in divergent chimneys was especially discussed in this study. The result of the mathematical model was compared with those of CFD simulation to evaluate the validity and the performance of this present model. Subsequently, parametric studies were conducted by using this mathematical model. The performance of divergent SCPPs was found to be governed by the area ratio of chimney entrance over its exit. The result further indicated that the optimal area ratio of divergent chimneys was different when the chimney height varied from 100m to 300m. Besides, several shorter divergent SCPPs showed a comparable power output as the cylindrical SCPPs with taller chimneys, which demonstrated an outstanding advantage of divergent SCPPs for commercial application.