AIMFAST: Initial Dish System Alignments Results Using Fringe Reflection Methods

The proper alignment of facets on a dish engine system is critical to the performance of the system. Improper alignment can lead to poor performance and shortened life, through excessively high flux on the receiver surfaces, imbalanced power on multicylinder engines, and intercept losses at the aperture. Alignment approaches used in the past are time consuming field operations, typically taking 4–6 hours per dish with 40–80 facets on the dish. Production systems will need rapid, accurate alignment implemented in a fraction of an hour. In this paper, we present an AIMFAST characterization of a Stirling Energy Systems dish, before and after implementing an alignment using the AIMFAST software. The results of the alignment are correlated with fluxmapper measurements of the dish, and the improvement in the flux pattern projected to an engine receiver is calculated using Sandia’s CIRCE 2 dish optical modeling tool. The alignment substantially reduced the peak fluxes on the flat fluxmapper targets as well as the projection onto the receiver. The fluxmap images correlate well with the CIRCE projections of measured facet normals. In addition, we implemented automated actuation of the facet during alignment, improving the response and accuracy of the system, resulting in total dish alignments with under 0.1 mrad RMS alignment error. We also implemented an adaptive alignment strategy that varied the alignment based on the AIMFAST-measured facet shape.