Comparison of the energy yield predictions of stationary and dynamic solar collector models and the models' accuracy in the description of a vacuum tube collector

One stationary and five dynamic models for solar collectors are analyzed in different ways. (1) The models are fitted to a set of measured data and the resulting collector parameters are compared. (2) Step responses of the models are compared in order to illustrate their different reactions to transient conditions. (3) The total daily energy yield predicted by the models for three days of different weather conditions is calculated using a reference collector parameter set. It turns out that the stationary model overpredicts the collector output by up to 15% in the case of one-minute averages of input data, while all dynamic models yield similar results. In the case of hourly input data, the error of the stationary model nearly vanishes.