Glazing Effects on Dynamic‐Insulation TSC Façades: A CFD‐Supported Experimental Study of Flow, Heat Transfer, and Ventilation Preheating

ABSTRACT Transpired solar collectors preheat ventilation air and reduce heat loss through building envelopes, but the effect of glazing remains insufficiently resolved. This study combines experiments, computational fluid dynamics, and techno‐economic analysis to compare glazed and unglazed collectors sharing the same 6 m 2 perforated absorber, 0.35% porosity and 110 mm plenum. Tests covered solar irradiance of 200–1000 W/m 2 and specific airflow rates of 18–144 m 3 /(h·m 2 ). The CFD model was validated against outlet‐temperature rise, absorber‐temperature distribution, and plenum‐centreline velocity and was used to interpret the internal flow and heat‐transfer mechanisms. The glazed collector achieved thermal efficiencies of 48%–75%, compared with 42%–65% for the unglazed collector. The model‐derived energy balance showed that glazing increased the useful‐heat fraction from 55% to 62%, mainly by reducing convective loss from 26% to 17%, while introducing a 5% optical loss. The unglazed collector exhibited slightly higher heat‐exchange effectiveness, whereas the glazed collector produced higher absorber and outlet‐air temperatures. At module level, their heating functions were complementary: the unglazed collector's wall heat‐loss recapture index decreased from 93% to 63%, while the glazed collector reduced ventilation‐heating load by 60%–90%. The glazed configuration also achieved passive efficiency above 50% at the upper tested cavity heights. Including rated fan input reduced efficiency by about three percentage points for both systems. The glazed collector delivered approximately 11% more modelled seasonal useful heat, while discounted payback was 5.5 years for the unglazed system and 6.8 years for the glazed system. Collector selection should therefore balance heat delivery, dynamic insulation, passive‐operation potential, maintenance, and capital recovery.