Design and development of an optical system for obtaining fixed orientation of concentrated sunlight for indoor applications

Abstract

A novel apparatus has been designed, simulated and fabricated to harness solar energy for indoor solar cooking and day lighting purposes. Herein, a fixed orientation collimated beam of concentrated sunlight has been achieved irrespective of the sun’s position using three optical components, viz. concentrator, reflector and collimator with a dual axis tracking system. Two different designs were simulated using optical ray tracing simulations and the optical output was compared. The first design uses a paraboloidal reflector while the second design uses a Fresnel lens as concentrator. Simulation results show that the first design employing paraboloidal reflector has 52.5% optical loss just after the collimator and 52.9% loss at a 4 m distance from the collimator. Similarly, the second design has 50.6% optical loss just after the collimator and 61.8% loss at a 4 m distance from the collimator. The prototype of the Fresnel lens-based design with automatic dual axis tracking was fabricated and the system was tested from morning to evening. Stationary focal spot was observed throughout the day irrespective of the sun’s position demonstrating the feasibility of the system for transporting solar energy for indoor applications. Optical loss of the prototype system was measured and was compared with the simulation results. Optical loss for the prototype just after the collimator was found to be 61.6% which is in good agreement with the simulation results. Thus, the developed novel system can be used as an alternative and clean source of energy for indoor solar cooking and day lighting applications.