Optical efficiency improvement of solar power tower by employing and optimizing novel fin-like receivers

The optical efficiency of the solar receiver is important to the global efficiency of the solar power tower plant. However, the present commercial cylindrical receiver causes a considerable optical loss because most of the sunrays reflected by the receiver surface are lost to the environment. To improve optical efficiency, three novel receivers with vertical finned structures and two novel receivers with horizontal finned structures are proposed in this paper. The optimal configurations of these receivers are obtained after parametric optimization. The optical efficiency and solar fluxes distributions of the optimal novel receivers are compared with those of the traditional cylindrical receiver at the noon of spring equinox. The results show that there is an optimal fin number of 6 for all the receivers with vertical finned structures. The receiver with vertical finned structures and the flat bottom shows the maximal optical efficiency of 63.9%. It indicates an improvement of 3.2 percentage points compared with that of the traditional cylindrical receiver. The receiver with horizontal fins with flat bottom shows the minimal optical efficiency of 60.3% at the noon of the spring equinox. It indicates a decrease of 0.4 percentage points compared with that of the traditional cylindrical receiver. Additionally, the peak solar fluxes on the novel receivers are quite close to each other and are nearly double that of the traditional cylindrical receiver. In the end, a multi-point aiming strategy is applied to the optimal novel receivers, and the results show that the peak fluxes can be obviously reduced. It is concluded that optical efficiency can be effectively improved by using the receivers with vertical finned structures.