Implementation of Spectral Splitting in a Hybrid Concentrator Photovoltaic and Thermal Solar Collector

Supplying the world with energy from fossil and nuclear sources was necessary to drive the industrialisation within the last two centuries and to achieve this high living standard no one wants to miss. However, time has come to start changing the world´s energy supply completely, as the impacts of global warming caused by burning fossil fuels are already immense. The ways into a sustainable future are various. Combining the different opportunities of renewable energies and developing new ones will be one of the most difficult challenges for the current and the following generations. The direct use of solar energy with photovoltaic and solar thermal systems is predicted to be one of the key technologies for covering our energy demand in the future. The concentrating hybrid collector described in this master thesis combines both systems in one component and provides electricity and hot water simultaneously. Further development of this collector shall increase the output temperature of its thermal output to 150°C by introducing the technology of spectral splitting. Therefore, this project work should deliver basic information about the planned modifications of the collector by simulating the current design, performing material investigations, preparing the test rig for measurements and conducting performance measurements under different conditions. The result of the simulation confirms the general constructive disadvantage of Fresnel systems delivering lower performance at low elevation angles. Propylene glycol indicated the best suitability as heat transfer fluid for this application, as the material investigation pointed out. Modifying the measurement setup on the test rig was a time-consuming but essential part of this project to be able to perform the following measurements, which provided thermal and electrical performances of the system including spectral splitting under different operating conditions. Further work on all mentioned topics is recommended to gain more experience with the new technology of spectral splitting. Nevertheless, this concept shows high potential to achieve the targeted output temperature of the hybrid collector and therefore widen its range of application.