2 Previous studies have attempted to enhance the efficiency of solar receivers at high temperatures by increasing solar absorptivity and reducing thermal emissivity by applying special coatings on the receiver’s surface. 1 However, at this temperatures the radiative heat loss (~T 4) is significant, while at high irradiance levels (>300–500 kW/m 2), reflected solar adiation losses can also be large. Compared to the base case analysis (flat tubular panel), the novel tubular panels have shown an increase in effective solar absorptance and thermal efficiency by several percentage points.Ī new generation of solar receivers that are capable of achieving temperatures over 600☌ are required in order to achieve cycle efficiencies of ≈ 50%. The thermal efficiency was then evaluated by coupling computational fluid dynamics with the ray-tracing results using ANSYS Fluent. The effective solar absorptance of the chosen tube geometries and panel configurations were evaluated using the ray-tracing modeling capabilities of SolTrace. Several panel geometries were initially proposed and were down-selected based on structural analyses considering the thermal and pressure loading requirements of molten salt and supercritical carbon-dioxide receivers. The overarching goal of this work is to achieve effective solar absorptances of ~90% and thermal efficiencies above 85% without using an absorptance coating. Similarly, the impact of the incidence angle on the effective solar absorptance and thermal efficiency is evaluated. This paper presents the thermal efficiency evaluation of novel receiver tubular panels that have a higher effective solar absorptance due to a light-trapping effect created by arranging the tubes in each panel into unique geometric configurations. However, these coatings degrade over time and must be reapplied, increasing the receiver maintenance cost. Previous and current tubular receivers, such as the ones used in Solar One, Solar Two, and most recently the Ivanpah solar plants, have used a black paint coating to increase the solar absorptance of the receiver. Traditional tubular receivers used in concentrating solar power are formed using tubes connected to manifolds to form panels which in turn are arranged in cylindrical or rectangular shapes.