Research and Optimization of Heliostat Field Layout Based on Mixed Strategy Whale Optimization Algorithm

In the tower solar thermal power generation system, the heliostat field,as an important part of the concentrating system,accounts for about 40%~50% of the total investment cost of the power station, and is directly related to the energy absorption of the absorption tower, so a reasonably arranged heliostat field is particularly important for the tower solar thermal power station. When the construction of the heliostatic mirror field is completed, its layout and related parameters are difficult to be changed again. In order to improve the comprehensive cost performance of the power station,the optimization of the mirror ficld has become one of the indispensable links in the design process. At present, in the field of tower photothermal light, researchers have done a lot of research on concentrating systems,but there are still some problems.It is mainly divided into the following two aspects: Most of the existing mirror field layout studies focus on the regular round and square layout. At the same time,the mathematical model in the layout is not detailed. After optimizing the layout, most studies only describe the improvement of the performance of the mirror field,but rarely explain the change of the layout parameters; In the evaluation of the mirror field performance,the optical efficiency is usually taken as an important measure. but for the shadow occlusion efficiency in the optical efficiency component,many studies do not give specific calculation details duc to the complicated calculation process and the mutual influence between the heliostat. For the above problems, the new heliostatic field layout derived based on the idea of radiation grid layout and the no-occlusion principle is studied。At the same time, the detailed calculation process of the shadow occlusion efficiency is given in the process of establishing the optical efficiency model, and then the key parameters in the mirror field layout are optimized in combination with the intelligent optimization algorithm. The main research contents are as follows: (1)Three tower heliostat field layouts, EB, No blocking-dense, and DELSOL derived from the radial staggered layout and the principle of No blocking-dense loss, are studied. After summarizing the layout mathematical models of the thrce heliostat ficld layouts. The change curve of the radial spacing and the azimuth spacing are obtained from the coordinate data of the mirror fields to verify the rationality of the mathematical model, and analyze the number of heliostine mirrors, optical efficiency,land utilization rate and received energy of the mirror fields in each layout. (2)The various optical efficiency of heliostat is conducted for modeling, and the calculation process and details of shadow occlusion efficiency are carefully deduced. Later, MATLAB and SolarPILOT software were applied to calculate the efficieney of the heliostaticscope field of the same coordinate data, respectively,and the efficiency error did not exceed士3%. (3)After improving the whale optimization algorithm.the MSWOA. WOA.GSA.and the results of test functions show that the MSWOA algorithm is used for better optimization and convergence ability. Later, non-dominant ranking and crowding degree calculation are introduced to make the algorithm applicable to multi-objective optimization problems, and the ability of MSWOA. WOA and GA algorithms to solve two-objective optimization problems is tested on the ZDT test function set. The results show that the Pareto optimal solution set obtained by MWSOA algorithm has better convergence and distribution. (4)Combining the data from MSWOA algorithm and engineering instance GGemasolar power station, optimizing the key parameter azimuth spacing factor Asf and limit reset factor Arlim in the EB layout were optimized with single and double objectives,respectively.The optimal layout scheme is thus obtained.