The flat-plate solar collector has been treated as a regulation object. An analog model of dynamics of the collector, based on the equivalent thermal network (ETN) method, has been proposed. The solar collector has been presented as an electrical circuit and has been calculated as a four-terminal network. Model was based on the construction and operating parameters of the collector, which allowed to shape the dynamics of work already at the stage of its design. An innovative solution has been proposed that has not yet appeared in the subject. The analog model has been verified on the digital model determined by experiment with using the parametric identification method. The models are to be used in designing of systems and algorithms for controlling of operation of hybrid supply systems. Transfer functions and step responses for both collector models (analog and digital) has been analyzed.