CFD Simulation of Airflow in a New Receiver Concept for High-Temperature Solar Heating

Abstract

Open cavity solar receivers play an important role in concentrated solar power (CSP) systems and hold great promise, particularly in scenarios where their ability to absorb high fluxes at very high temperatures yields beneficial results. This intense concentration of sunlight can be used to produce electricity through various means, such as generating steam to drive a turbine. The efficiency of the open volumetric receiver concept relies heavily on the air return ratio (ARR) which refers to the proportion of air recirculated and returned to the receiver. A high ARR contributes to high receiver efficiencies, as with rising ARR, the reused part of the enthalpy of warm air increases. This paper deals with the design and simulation of a new receiver concept with a conical cavity and square cross-section. The objective is to identify the most effective design arrangement for the square-cone structure, considering different depths, that maximizes both the air return ratio (ARR) and thermal efficiency. The findings demonstrate that increasing the depth of the mentioned receiver leads to a rise in the ARR, up to a certain threshold which can reach values up to 94,53 %, beyond which there is a subsequent decline in efficiency. Furthermore, this study examined how varying the amount of air passing through a specific section of the receiver across a defined area, along with the temperature changes in these sections, affected its operational efficiency.