| Abstrakt: |
The thermochemical process of syngas production, exploiting concentrated solar power, requires thermal energy at very high temperature, in the order of 1000-1500 °C, well beyond the maximum operating temperature of actual commercial receivers. The absorbing gas solar receiver, proposed by Synhelion SA, represents a breakthrough in the point focus solar technology allowing to operate at temperature levels higher than 1500 °C. This innovative cavity-type receiver exploits thermal radiation, as major heat transfer mechanism, for directly heating the gaseous heat transfer fluid (water vapor or carbon dioxide). Given the complexity of the physical phenomena taking place into the receiver, a CFD-based approach was followed to accurately replicate its thermo-fluid dynamics behavior under different operating conditions. In detail, a total of three CFD simulations campaigns, assuming the receiver operating at ambient pressure or at 10 bars, were performed with the aim of evaluating the effect of important parameters, such as heat transfer fluid entrance angle, gravity and realistic concentrated solar flux distribution into the cavity, on the receiver performance. An incoming concentrated solar flux on the aperture of 1.2 MW/m2 (corresponding to 600 kW/m2 on the absorptive surfaces) was assumed as reference leading to a total input power of 120 MW and 240 kW in the case of unpressurized and pressurized receiver respectively. According to the results obtained, gravity resulted to be the parameter with major influence followed by realistic concentrated solar flux distribution and heat transfer fluid entrance angle. However, a minimum receiver thermal efficiency of 66%, at about 1600 °C outflow temperature, was observed under the worst operating conditions considered indicating the reliability and robustness of this innovative receiver deign. [ABSTRACT FROM AUTHOR] |
