Numerical investigation and multi-objective thermo-economic optimization of a solar chimney power plant

This study was conducted to optimize a solar chimney power plant from the aspects of performance improvement and cost saving. Numerical simulation was performed for a Spanish prototype to investigate the parametric sensitivity of several key variables and identify a reasonable range for the variables as the constraints of the optimization. A multi-objective optimization on the prototype was conducted using orthogonal design of experiments, response surface methodology, and the non-dominated sorting genetic algorithm. The optimum chimney diameter tends to reach the upper bound of 30 m, while the optimum collector radius is almost uniformly distributed over the allowable range. The optimum range of the turbine pressure drop ratio is between 0.82 and 0.88 for the cases with a 200-m high chimney. The optimized capital cost per unit power production ranges from 0.018 to 0.026 M€/kW, which is much less than 0.054 M€/kW of the Spanish prototype. Considering the output power and construction cost comprehensively, the Pareto solution set obtained from the optimization may provide a guide to the system design and operation.