Black-box identification of solar collector dynamics with variant time delay

This paper treats black-box identification of the solar collectors at an air conditioning plant. The collectors have nonlinear dynamics and a flow variant time delay that complicates the use of conventional black-box identification methods. A method for compensation of such flow variant time delays is proposed. Thereafter a black-box method for nonlinear systems without time delays can be applied. The obtained nonlinear model describes the collector dynamics well, and has a mean square of the prediction error of the output that is approximately 10 times smaller than that obtained for the best linear model achieved by the same method.