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

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 increases 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 Acciona Industrial, S.A., Thermal Power Engineering, S.L., Applied Research Institute for Prospective Technologies, 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 tube material costs can be saved, while for the 100 MWe asymmetric design case, more than 13% of the tube material 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%). As of now, the EPC cost is reduced by 14.41%, and the combination of the solar field, solar receiver and power block optimization has increased the global efficiency of the plant with 2.96%. An LCOE reduction of up to 13.34% 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 EurostarsTM-2 program as well as funding from Innovation Fund Denmark.