Optimization of an asymmetric solar receiver design in high-performance thermosolar plant in synergy with PV-hybrid autonomous heliostats Free

The PHOTON project, also titled “High Performance Thermosolar Plants based on PV-Hybrid Autonomous Heliostats and Tailored Receivers”, aims to obtain a new and competitive solar thermal electric plant configuration, simplifying the current assembly and commissioning operations. The project targets an increase in the global plant efficiency and improvements of the production/cost ratio making solar power a dispatchable competitive energy source. Within the project, Aalborg CSP A/S collaborates with the four project partners (abbreviated as) Acciona, Tewer, Protech, and Metsolar, to reach the project vision. This paper concerns Aalborg CSP's part in the project concerning development, design, and optimization of the solar thermal power tower molten solar receiver (MSR), in synergy with the PV-hybrid autonomous heliostat development. When comparing the MSR geometry, it is found that the asymmetric MSR designs score higher ratings than both the symmetric and base case designs. The 50 MWe asymmetric design is found to be more pronounced than the 100 MWe asymmetric design, since the 50 MWe design case requires a smaller solar field, thereby obtaining a higher optical quality of the heliostats. For the 50 MWe asymmetric design case, more than 20% of the overall MS receiver costs can be saved, while for the 100 MWe asymmetric design case, more than 13% of the overall MS receiver costs can be saved. The MSR efficiency increases from 91.8 to 92.1 for the 100 MWe design case, and from 91.3 to 92.1 for the 50 MWe design case. However, in all current simulations, Pyromark 2500 has been applied. It should be noted that the MSR efficiency can be further increased based on alternative coating selections (indications show up to 2.94%, when applying a novel non-commercial, multi-layer absorber coating, patented in 2019, in the calculations. The referred coating has been presented twice at the SolarPACES conference, both in 2018 and 2019, with its high-absorption, high-durability performance tests and findings). As of August 2019, the EPC cost is reduced by 14.4%, and the combination of the solar field, solar receiver and power block optimization has increased the global efficiency of the plant by 2.96%. An LCOE reduction of up to 13.3% has been achieved, resulting in less space requirements (e.g. up to 29.7% for the solar field in the 100 MWe-case with two-facet heliostats) and less solar energy requirements to produce the same amount of electricity annually as the base cases. Furthermore, improvements have been implemented in the power block system to reduce the auxiliary consumptions during normal operation. The project has received financial support from the Eurostars^TM-2 program as well as funding from Innovation Fund Denmark.