Mass Flow, Pressure Drop, and Leakage Dependent Modeling and Characterization of Solar Air Collectors

In comparison to liquid collectors, the thermal efficiency of air collectors strongly depends on the mass flow, and often air collectors can be leaky. Further, for efficient system operation, the air collector's mass flow will be chosen regarding the auxiliary power demand of the fan caused by the pressure drop of the system. In this work the interdependency between thermal and hydraulic behavior and the resulting primary energy demand will be explained. Moreover, suitable mass flow dependent models for thermal efficiency, pressure drop and leakage will be presented. Because of the mass flow dependent correlation of the thermal power gain and the auxiliary power demand, a novel characterization method for air collectors will be proposed considering both.