SolarPACES Guideline for Heliostat Performance Testing

Abstract

This guideline focuses on Concentrating Solar Technologies (CST). Power tower or central receiver systems use 2-axis tracking mirrors, so called heliostats, which reflect and focus the sunlight onto a receiver on top of a tower during the day for heat, electricity or fuel production. The content is fed into the IEC 62862-4-3 Part 4-3: Heliostat requirements and testing started in 2023. The Heliostat Performance Testing guideline is directed to single heliostats of CST central receiver systems. It focuses on the definition of parameters and performance testing of single heliostats during a limited time period. Measurement techniques or other techniques to derive the heliostat parameters are suggested. Durability issues are treated in this guideline only in the sense that the heliostat performance can be tested from time to time. Accelerated ageing and durability tests are not in the scope of this guideline. Although performance testing of a whole heliostat field (consisting of several heliostats with blocking/shading effects, aimpoints issues, etc.) will be based on the Heliostat Performance Testing guideline, the aspects of interaction of the heliostats in a solar field will be treated in a separate guideline called Heliostat Field Performance Acceptance Test Guideline. The objective of this guideline is to serve as a commonly agreed protocol between R&D centers and industry in the field of heliostat performance testing. It is ready to be included in international standards (e.g. IEC) and should be used by national organizations like DKE, AENOR, ASME, ASTM and international organizations for this purpose. The application of this guideline will result in homogenized content of heliostat test certificates which are issued by the different qualification centers. Consequently, bankability of new heliostats should be facilitated. The objective of performance testing of different heliostats according to protocols is to assess heliostat performance on an objective, scientific, but practical level.