Testing of a Secondary Concentrator Integrated with a Beam-Down Tower System under Non-liquid Cooling Strategies

Abstract

© 2018 Author(s). Three dimensional secondary concentrators are exposed to high radiation fluxes, part of which is absorbed by the reflecting material, leading to elevated wall temperatures which may cause reflectance degradation and mechanical distortion. Temperature monitoring and thermal management is required. Existing 3D secondary concentrators used in beam-up or beam-down tower plants use water-based convective cooling for which failures and leaks have been reported. The present work tested two alternative non-liquid-based cooling strategies: enhanced radiative cooling using a high-emissivity paint and forced-air convective cooling. The concentrator under no cooling enhancement reached temperatures above the acceptable limit, indicating the need for better cooling. Forced-convective cooling had the most noticeable effect and proved sufficient for the considered testing conditions. The impact of radiative cooling enhancement was lower in the considered incident flux conditions, as the initial temperature without enhancement was relatively low.