Design, theoretical, and experimental thermal analysis of a solar collector with flat mirrors mounted on a parabolic surface

Flat mirrors are used in Fresnel collectors. Mirrors arranged on the right and left reflect the sun’s rays from a distance to the absorber. Meanwhile, parabolic transition-type collectors feature a reflective mirrored parabolic surface and are manufactured as a single unit. In this system, mirrors cut into 11 cm dimensions are placed on a parabolic surface. By incorporating flat mirrors onto the parabolic surface, a hybrib system combining parabolic and Fresnel collector types is created. The parabolic collector has an area of 15 m² with dimensions of 3.35 m × 4.5 m. This system tracks the sun in an east-west direction. Heat transfer oil is used as the heat transfer fluid of the system. In the experiment, the temperatures at the inlet and outlet, the glass tube in the absorber, and ambient temperatures were recorded. Theoretical thermal power and thermal efficiency results were compared with those obtained from experimental measurements. Findings indicate that the thermal efficiency of this system with a thermal power of 4 kW is around 30 %–39 %.