Novel design of central dual-receiver for solar power tower

A novel dual-receiver with a surrounding solar field was proposed to improve the efficiency of a solar power tower (SPT). The new design combined an external and a cavity receiver, corresponding to the boiling and superheating sections respectively, and provided a simple yet controllable heat flux distribution on both sections. A case study of a 11 MW solar power plant was conducted. It was demonstrated that the present dual-receiver could produce superheated steam of 515 °C and 10.7 MPa at an impressive solar heat absorbing efficiency of 86.55%. By considering various heat losses, the surface heat flux, the surface temperature and the heat transfer fluid distribution were obtained for the dual-receiver. A comparison with a two-external cylindrical receiver showed that the present design could improve the global thermal efficiency by 3.2%. Off-design performance of the dual-receiver indicated that the plant performance was affected significantly by the incident solar fluxes at different times of a day. The influence of heat transfer tube size suggested that an optimized tube diameter for the superheating section of the present dual-receiver should be used