A New Methodology for Building-Up a Robust Model for Heliostat Field Flux Characterization

Abstract

Abstract:The heliostat field of solar central receiver systems (SCRS) is formed by hundreds, even thousands, of working heliostats. Their adequate configuration and control define a currently active research line. For instance, automatic aiming methodologies of existing heliostat fields are being widely studied. In general, control techniques require a model of the system to be controlled in order to obtain an estimation of its states. However, this kind of information may not be available or may be hard to obtain for every plant to be studied. In this work, an innovative methodology for data-based analytical heliostat field characterization is proposed and described. It formalizes the way in which the behavior of a whole field can be derived from the study of its more descriptive parts. By successfully applying this procedure, the instantaneous behavior of a field could be expressed by a reduced set of expressions that can be seen as a field descriptor. It is not intended to replace real experimentation but to enhance researchers' autonomy to build their own reliable and portable synthetic datasets at preliminary stages of their work. The methodology proposed in this paper is successfully applied to a virtual field. Only 30 heliostats out of 541 were studied to characterize the whole field. For the validation set, the average difference in power between the flux maps directly fitted from the measured information and the estimated ones is only of 0.67% (just 0.10946 kW/m 2 of root-mean-square error, on average, between them). According to these results, a consistent field descriptor can be built by applying the proposed methodology, which is hence ready for use.

Experimental and Numerical Investigations of Solar Flux Density Distribution Over Flat Plate Receiver of Model Heliostat System

“…Venkatesh et al [24] developed a dimensionless correlation with respect to tower height and receiver size (diameter and height) as a function of heliostat size and its position in the field. Nicolás C. Cruz [25] had been proposed and described an innovative methodology for data-based analytical characterization of the heliostat field and modelled a whole heliostat field by a reduced set of analytical expressions.…”