Experimental demonstration and validation of tubular solar cavity receivers for simultaneous generation of superheated steam and hot air

Cavity receivers with absorber tubes inside the solar tower systems are the most studied and suitable concept for supplying such hot steam and air due to its design flexibility and efficiency. However, a receiver concept of simultaneously generating high-temperature steam and air has not been experimentally studied on scales beyond laboratory scale. Therefore, our study focused on the experimental demonstration for such receiver concept and the validation of the developed numerical model. Experimental results demonstrated that the proposed receiver concept (i.e. a cavity receiver with cylindrical and conical helical tubes) with 70 kWth nominal power can simultaneously produce high-temperature steam (811 °C) and air (863 °C) with standard deviations of less than 3 °C (outlet temperature), 3 kPa (outlet pressure), and 0.2 kg/h (mass flow rate). Comparison of experiments and simulations proved to be in very good agreement, with errors of less than 10 %. The results presented here provide a basis for future scale-up and demonstrate the high potential of combining concentrating solar thermal technology with high-temperature electrolysis for the mass production of green hydrogen.