Secondary concentrators are used in combination with primary concentrators to form optical concentration systems to collect and focus solar energy to be used in a variety of applications including power conversion systems, thermal propulsion systems, and solar furnaces.

Secondary concentrators can be hollow reflective cones or solid single crystal refractive elements. GRC is interested in both types of secondaries, but has currently focused on the refractive secondary concentrator for higher power, higher temperature applications.

The refractive secondary concentrator uses refraction and total internal reflection to efficiently concentrate and direct solar energy. The refractive secondary offers very high throughput efficiencies (> 90%), and when used in combination with advanced primary concentrators, enables very high concentration ratios (10,000 to 1) and very high temperatures (> 2000 K).

• How a refractive secondary works
• Benefits of a refractive secondary
• Transient thermal modeling of the refractive secondary

Projects:

• Space Solar Power (SSP) - refractive secondary as part of a solar dynamic power system.
• Shooting Star Solar Thermal Propulsion - refractive secondary as part of a solar thermal propulsion flight experiment
• AITP Ground Demo - refractive secondary designed for a solar thermal propulsion ground demonstration

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Last Updated: 07/30/2002