Numerical analysis of wind-induced convective heat losses in large-scale open volumetric cavity receivers and the evaluation of countermeasures

Abstract

This study investigates the wind influence on the operation of an open volumetric cavity receiver (OVR) designed with a tower height of approximately 200m and a total thermal power of 240MWth. The receiver design incorporates an air return system where parts of the air are returned between the OVR modules after the heat exchange, while the remainder is recirculated externally from below the receiver. When operating such a scaled-up OVR, ambient wind becomes a relevant parameter in terms of convective losses and the air return ratio, which must be maintained at a high level to ensure economic viability. In this study, ambient wind and the receiver flow are modelled by CFD simulations with the RANS approach. In addition to the evaluation under windless conditions, the simulations in this study cover lateral wind at 4 and 8ms wind speed. The simulations show the vulnerability of externally returned air as it is significantly influenced by lateral wind. As a countermeasure, wind-adjusted external return air distributions are investigated, which show the potential to reduce convective heat losses due to incomplete air return. In addition, the application of aerowindows is investigated, which has limited potential due to the size of the receiver aperture. The results highlight the importance of the design of the external air return system and suggest a controllable return air system that can be adapted to the current wind situation.