A numerical model to evaluate the flow distribution in large solar collector fields in different operating conditions

A numerical model to evaluate the flow distribution in a large solar collector field was developed in Matlab and is presented in this study. Model and measurements from a solar collector field were compared and a good agreement was found. The model was then used to study the flow distribution in different an-ay layouts.

Balancing valves proved to he an effective way to achieve uniform flow distribution also in conditions different from those for which the valves were regulated, as well as in case of irregular layouts with different compositions of the collector rows. A Tichelmann connection gave a uniform flow distribution, especially if the distribution pipe diameter is reduced so to give a constant pressure drop gradient.

The reduction in power output from the collector field was approximately proportional to the square of the root-mean-square deviation of the flow distribution, but was generally small, at least under the considered assumptions.