Analysis of temperature measurements on solar absorber coatings under concentrated solar flux

Kurzfassung

Among CSP systems, solar power tower yield the highest efficiencies of up to 23...35 %, with current working fluid temperatures of about 600 ◦C [5]. While on the one side, a lot of research is invested to reach higher temperatures [6], the cost and benefit for the LCOE has to be considered on the other side. A great part of the total solar power tower LCOE with 98...181$(MWh)−1 is related to the costs of solar receiver and their coatings, converting the concentrated sunlight into heat [5], [3]. Since various aspects, such as absorptivity, emissivity, degradation and reapplication effect the receiver coatings, the levelized cost of coating (LCOC) was introduced to compare different coatings [7]. To reduce this LCOC, one part of the RAISELIFE project aims to increase the coatings lifetime [8]. Therefore researches are carried out with accelerated aging campaigns [9]. In this context the following work concerns with the infrared temperature measurement of receiver coatings, which is essential in numerous aspects. From an industrial point of view, the optimal temperature has to be regulated and monitored, to increase the efficiency, while preventing an overheating of the receiver. For the related research campaign, knowledge about the temperature is furthermore necessary to investigate and compare the durabilities of the receiver coatings. This work is divided into the following four chapters. The chapter 2 (Infrared thermography), concerns theoretical aspects of radiation and infrared measurement. The next chapter 3 (Methodology), defines the boundary conditions of the measurement setup and applies the theoretical findings. The chapter 4 (Results and discussions) gives the findings of the measurements and discusses its validity. The last chapter 5 (Conclusion) summarizes the whole work and shows potentials of improvement.