Experimental and numerical analysis of a new hybrid type solar air collector

The main reasons why the use of solar air collectors, which is one of the simplest ways to transfer heat from solar energy to the air, is not widespread is the low thermal efficiency of the collector and the lack of continuity of thermal energy due to solar radiation. In previous studies to increase the thermal efficiency of the collector; researches have been carried out on the effect of thermal efficiency of geometrical structures (distance between collector absorber plate and jet plate, distances between jet holes, geometries of jet holes as circle or square, use of rough surface absorber plate in jet impact collectors, depth of air duct) and air flow shape (parallel, unidirectional and opposing flow conditions of air in the duct, laminar and turbulent flow conditions, jet and different flow encounter angles where flow diverters of different geometries are used together) of the collectors. In this thesis study; the effect of jet impinging to the absorber plate with smooth surface, hemispherical rough surface and sinusoidal surface the jet flow passing through conical nozzles of different geometries on the jet impact plate in solar air collectors on the thermal efficiency of the collector was investigated experimentally and numerically. To obtain the optimum configuration of the collectors in order to maximize heat gain and increase heat transfer, different geometrically shaped jet impact plates and different shaped absorber plates inside the collector case are designed to be removable and reinstallable. From the experimental and numerical analysis, it is observed that the thermal efficiency of the jet-impact air solar collector using hemispherical absorber plate and circular conical nozzle pair (HAP-CTN) provides an increase of 12.33% on the average outlet temperature compared to the jet-impact air solar collector with flat absorber plate. In the experimental study for the same combinations in JIPSAC using HAP-CTN pair, the highest average efficiency of the collector was 0.0185 kg/h. mass flow rate was 24.5% and the highest average collector outlet temperature was 47.8 oC. Experimental and numerical studies have shown that for optimum collector efficiency, collector outlet temperature and laminar flow on the jet plate, Sinusoidal Absorber plate and conical jet nozzle with circular cross section (SAP- CTN-JIPSAC) are more compatible. In this configuration, the average collector efficiency is 54%, the average collector outlet temperature is 71.2 oC and the useful energy obtained from the collector is 625 W.