High-Resolution Flux Measurement for High-Flux Solar Simulators: Characterisation of Irradiance Distribution with a Thermopile

Concentrated solar power (CSP) systems impose high demands on individual components such as receivers, optical elements, etc. due to high solar flux. Characterisation of these components often requires measurements under defined, constant conditions, which can be challenging or even impossible in real-world applications due to changes in irradiance, weather conditions, accessibility, tracking inaccuracies, etc. . Solar simulators are used for this purpose, with the challenge of providing sun-like, uniformly distributed and highly concentrated light. This paper presents an approach to automatically investigate the irradiance distribution of concentrated light in a solar simulator. A water-cooled flux meter (thermopile) is used in combination with an XY table to scan the area of interest, resulting in a high-resolution image of the irradiance distribution in the target area. The results are presented and discussed based on measurement data recorded in a real solar simulator. Issues such as sensor area i.e. spatial resolution, light spectrum dependence, temperature influence, and measurement speed are addressed.