Optical-thermal-mechanical analysis of high-temperature receiver integrated with gradually sparse biomimetic heliostat field layouts for the next-generation solar power tower

Three gradually sparse biomimetic (GSB) heliostat field layouts, which gradually extend from the inside to the outside, are proposed herein. Annual optical performance is compared with the standard biomimetic (SB) layout and the widely used staggered layout. In the end, the receiver's optical-thermal–mechanical performance is analyzed with the above five heliostat fields for the next-generation solar power tower (SPT) with the receiver's outlet temperature at 720 °C. The results show that the GSB layout with a linear increasing factor (Linear-GSB) has the best optical performance. Compared with the staggered layout and the SB layout, the Linear-GSB layout can increase the annual intercepted energy (E_ann) by 1.5% and 1.3% under the same heliostat number, respectively. Moreover, GSB layouts can simultaneously reduce the receiver's maximum heat flux (q_max), maximum thermal stress (σ_w,max) and improve its heat flux distribution homogeneity. Compared with the staggered layout, q_max, σ_w,max, and heat flux maldistribution index of the receiver under the Linear-GSB layout at noon of spring equinox are decreased by 4.2%, 4.3%, and 19.8%, respectively. Meanwhile, the Linear-GSB layout can achieve slightly higher receiver efficiency compared with the staggered layout.