Optical Simulation Of Heliostat Field In Solar Tower Power System And Its Application

The solar tower thermal power system has drawn more and more attention as an ideal method to produce electricity in large scale. The concentrating subsystem which provides the energy the plant needs is the basis of the whole system. But its cost is enormous. Therefore there has been plenty of research focused on the simulation of the concentrating subsystem. However commonality of current simulation software or codes is not satisfied and the accuracy and calculation speed might be sacrificed when dealing with large number of heliostats or with some complex sunray model. On the other hand, the simulation research in recent years has been concentrated on the design of the heliostat field, but not the operation optimization.To solve the problems above, this thesis mainly focus on the optical simulation of the heliostat field, acceleration of the algorithm, and application based on the proposed simulation method. The main contributions of this thesis are as follows.1. All the elements involved in the transmitting of the sunlight are described, including the heliostat field and the receiver. The meaning and components of the optical efficiency are analyzed. The efficiency of the whole field is calculated based on the optical efficiency of one single heliostat. The validity of the code is verified by the simulation results of several heliostat fields.2. The Graphic Processing Unit (GPU) and the CUDA platform is used to accelerate the method of calculating the optical efficiency of the field with parallel computing. The running speed is obviously increased with no loss to the accuracy.3. Based on the GPU codes for the efficiency calculation, heliostat schedule is studied. Various schedule strategies are proposed in the case of open-loop and closed-loop. The effectiveness of the methods is demonstrated by the simulation results.4. The unparallel sun ray model is studied, and the discrete convolution was used combined with imaging projecting. The image on the receiver of one light cone, one heliostat and multi-heliostat are simulated. Consequently the interception efficiency was calculated.