Concept and initial design of a stationary concentrator photovoltaic system based on a mirror array

We propose a stationary module in which a mirror array is inserted between a lens and a solar cell. Each mirror is set up so that the light passing the principal point of the lens reaches a fixed point on an exit plane and that the length of its optical path is equal to the focal length of the lens. The light passing the other points in the lens reaches other mirrors. If the reflected light mostly reached the area near the fixed point, a slightly larger solar cell would harvest it. We have carried out ray tracing simulations to see how the optical power is distributed on an exit plane of such a module. The model consists of a hollow rectangular parallelepiped containing a mirror array, a plano-convex lens attached to the top plane of the parallelepiped, and a detector attached to one of the side planes. A light source generates parallel beams with various directions defined by the declination angle and the hour angle. Although the irradiance distribution at the exit plane depends on these angles, the basic concept of confining the optical power inside a certain area is demonstrated. Further studies on its design would improve its light utilization. For example, the rays with large incident angles suffer from total internal reflection at the bottom of the lens. Filling the hollow parallelepiped by a material with a matching refraction index solves this problem.