Progress on Integrated Compound Concentrator Design

Nonimaging optics has been playing an important role in both tracking and non-tracking devices used for solar applications. We will report on our progress on implementing the integrated design within a glass vacuum tube for a non-tracking solar thermal collector. Such a design allows a thermodynamically efficient concentrator to be used for any convex shaped absorber. The acceptance angle of the design is also optimized for the seasonal change of sun. To minimize the material cost of our design, the reflector is integrated with the shape of the evacuated tube. Compared to from the conventional parabolic trough receiver which utilizes bellows and double end seals, our design uses a single end metal glass seal and allows the other end to freely expand. A 0.7 meter prototype is constructed as a prototype. The optical efficiency and incident angular modifier are simulated using a ray tracing program to show that within the designed acceptance angle, the collector performs at around 78% optical efficiency.