Turbine layout for and optimization of solar chimney power conversion units

[摘要] ENGLISH ABSTRACT: The power conversion unit of a large solar chimney power plant converts the fluid power, first into mechanical power, and then into electrical power. In thisdissertation a tool is developed to determine the layout and the number of turbinesof the solar chimney power conversion unit providing the lowest cost ofelectricity.First, the history of the solar chimney concept and the related fields of researchare presented. Potential features and configurations of the power conversionunit are introduced, and it is shown how the solar chimney power conversionunit compares to those of other applications. An outline of the dissertationis given, and its potential impact is discussed.An analytical turbine model is developed. Several modelling approaches andthe performance of single rotor and counter rotating turbine layouts are compared.Preliminary turbine designs are investigated, experimentally and numerically.The main aim of the experimental investigation is to verify the applicabilityof the loss model used in the analytical turbine model. The aim of the numericalinvestigation is to evaluate a commercial software package as a tool in contextwith solar chimney turbines.For each component of the power conversion unit an analytical performancemodel is introduced. Using these models, the single vertical axis, multiple verticalaxis and multiple horizontal axis turbine configurations are compared froman efficiency and energy yield point of view, and the impact of the various losseson the overall performance is highlighted. A detailed cost model for the powerconversion unit is also presented. To optimize for cost of electricity this costmodel is then linked to the performance models, and the resulting optimizationscheme is applied to several plant configurations.It is shown that for a large solar chimney power plant the power conversionunit providing minimal cost of electricity consists of multiple horizontal axis turbinesusing a single rotor layout including inlet guide vanes.

[发布机构] Stellenbosch University