Flux Mapping

The flux distribution on central receivers can be computed rapidly and accurately by means of the convolution-projection method. As illustrated in the figure: (1) receiver panels are discretized in a mesh of equally spaced nodes, (2) mesh nodes are projected onto the image plane in the direction of the main reflected ray, (3) the analytic function is evaluated at the nodes in the image plane, and (4) the flux density is transferred to the receiver nodes, multiplying by the cosine of the incidence angle on the receiver panels. As reported in the references, this method has been validated against experiments and raytracing simulations.

The resulting code computes, not only the flux density distribution on the receiver, but also the heliostat optical loss factors (i.e. shading and blocking, spillage, cosine, atmospheric attenuation). Any heliostat field layout and receiver size can be introduced, resulting in a flexible tool. A freeware version, named FluxSPT, is available at ISE website.

Software tool

Related publications

Solar flux distribution on central receivers: Aiming factor to flatten the flux distribution on cylindrical receivers