Solar Collector Parameter Identification From Unsteady Data by a Discrete-Gradient Algorithm

Abstract

A discrete-gradient algorithm is used to identify the parameters in a one-node and a two-node capacitance model of a flat-plate collector. Collector parameters are first obtained by a linear-least-squares fit to steady state data. These parameters, together with the collector heat capacitances, are then separately determined from unsteady data by use of the discrete-gradient algorithm with less than 10 percent deviation from the steady-state determination. All data were obtained in the indoor solar simulator at the NASA Lewis Research Center.