Browsing by Author "Bode, Sebastian-James"
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- ItemDevelopment of a ray tracer for concentrating solar power systems(Stellenbosch : Stellenbosch University, 2017-12) Bode, Sebastian-James; Gauche, Paul; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: The world limate system is hanging and recent researh shows that man-made arbon dioxide emissions from proesses such as coal-fired power generation is the most likely cause. In South Afri a the bulk of eletricity generation comes from coal power plants. In addition to the possible environmental damage caused by these plants, South Africa's reliance on coal exposes the country to possible fuel shortages and rising fuel prices. Concentrating Solar Power (CSP), which uses lean, renewable solar energy for electricity generation, an possibly mitigate these risks and reduce South Africa's dependence on coal. However, for CSP to play a significant role in electriciity generation, its Levelised Cost of Electricity (LCOE) must be reduced. This an be achieved through research and development of CSP systems. Numerical software tools, such as ray tracing, play an essential role in design and optimisation of these systems. The aim of this research was to develop, program, and validate a CSP ray tracer which an be used for ongoing research at the Solar Thermal Energy Research Group (STERG) at Stellenbosch University. The ray tracer, which has been named SUNRAY (Stellenbosch UNiversity RAY tra er), was written in C++. It was developed with realisti sunshape and reflection modules, a number of geometric shapes, automatic tracking algorithms, acceleration routines, and a method to simulate actual mirror surface profiles using surface scanned data. SUNRAY has been extensively validated using behavioural tests, comparative tests against previously validated ray tra ers, and through experimental investigation. For the behavioural cases, it was found that SUNRAY was able to resolve the correct solution for every test. In the comparative tests the relative difference for the power and flux distribution between SUNRAY and validated ray tracers was, on average, no more than 0.4% and 3%, respetively. Furthermore, the execution times for the simulations were, in most cases, faster than that of the validated codes. In the experimental validation various mirror shape profiles were tested under different weather conditions. The experimental tests demonstrated that SUNRAY an be used to adequately determine the magnitude of flux and flux distribution on a target. This thesis presents the theory behind the various features, algorithms, and routines of SUNRAY as well as the validation of these features. Two novel algo- rithms are also proposed in this thesis. The first is a method which reduces the number of missed rays by only generating rays above each object in the simulation. The second uses statistical tools to predict the number of rays which are needed in a simulation.