Picture in Figure 1 was taken with a flash. The flash is reflecting off of a solar mirror sitting face up on the table in the foreground of the picture. The mirror is a rectangular shaped facet of high optical quality. The facet is shaped for a specific focal length. The facet is like those shown in the Stirling engine concentrator.
JPL Booth, Solar Energy Conference, Long Beach CA, 1980
Solar reflective mirror facets are a critical piece of optical technology. Good solar concentrator performance requires high accuracy in the reflection of the sun’s rays. The efficient collecting of the sun’s rays is expensive. Why? High quality optical equipment is required, and high quality optical equipment is expensive.
Figure 2: Test Bed Concentrator
Testing was conducted at Edwards AFB. The high optical quality facets were developed by JPL. The focal length of the facets increases from the center of the dish to the edge.