Extension of the hermite expansion method for cassegrainian solar central receiver systems

An extension of the Hermite Expansion Method for performance simulation of central receiver plants is presented. This extension allows simulation and parametric study for a solar central receiver plant based on Solar Concentration Off-Tower (SCOT, or Reflective Tower) design. The extension includes mapping the physical receiver aperture into a Virtual Receiver located near the field's aim point, and performing the Hermite Expansion calculation on the Virtual Receiver. The calculation of aperture intercept/spillage and additional losses due to the Tower Reflector's finite size are discussed. Validation of the extension by comparison to ray-tracing simulation is presented for single heliostats, a group of heliostats and a complete surround field. The results match closely, showing the validity of the method and of its implementation.