On the influence of rotation on thermal convection in a rotating cavity for solar receiver applications

In order to address the worldʹs high-energy demand, a novel particle receiver concept for concentrating solar power (CSP) plants has been developed. A key feature of the concept is to exploit a receiver rotation being able to adjust the receiver outlet temperature to different load states. Within the scope of identifying the thermal receiver efficiency investigations regarding convection losses of a rotating cavity are conducted. Special attention is paid to the effect of rotation on convective flow in a cylindrical cavity with heated side walls for solar applications. Experiments with a rotating cavity in laboratory scale have clearly revealed a negligible effect of rotation on convective losses in the considered rotation speed range. Compared to the influence of receiver inclination, where the convective losses can be decreased up to 90% for downward-facing receivers, rotation affects them only by at most ±10%. Considering overall thermal losses in the receiver (including conduction and radiation losses), the effect of rotation might be even less than 1% of the incoming solar power.