An innovative diffuse light concentrator with high efficiency and acceptance angle

Time period: 2019-12-02 to 2020-11-15

Project leader: Ilia Katardijev

Funder: Vinnova

Type of award: Project grant

Total fundning: 500 000 SEK

Purpose and goal: The main objective of the project was to design and evaluate the performance of a static light concentrator that concentrates sunlight regardless of the sun´s position in the sky and thus harvests both direct and indirect sunlight with an efficiency that significantly exceeds all current technologies. The project fulfilled its aim completely. The performance of the concentrator surpasses today´s technology for focusing diffuse light in many respects and not least has an efficiency that is only limited by fundamental laws of physics. Expected results and effects: Calculations based on the concentrator´s performance show that one can harvest over 82% of the solar radiation and under realistic conditions convert on average 70% of the original energy into usable forms of energy - electricity and heat. The technology is suitable for "roof-top" systems that can be integrated with the building´s roof and facade and is thought to lead to the development of energy-positive buildings and cities. The concentrators are made of recyclable optical materials which in the long run are expected to be replaced by water-based ones. Approach and implementation: The project is based on previous theoretical work by project manager. The light concentrator consists of a conical mirror which is filled with optical elements (OE) of a certain geometry. It is this geometry and the interaction between the OEs that results in the concentrator´s high performance. The OEs are made of recyclable optical materials such as plexiglass with injection moulding. Performance is evaluated optically by measuring the reflection coefficient as a function of the angle of incidence. The measurements are compared with theoretical calculations.