Experimental study of solar collector with helical coil

The solar parabolic trough concentrator (PTC) is superior to all other solar collectors owing to its concentration ratio. Various methods are being employed to enhance the efficiency of the PTC system, the most common of which are enhancing the reflectivity of the collector surface, increasing the absorptive capacity of the absorber tube, using high thermal capacity fluid in the absorber tube, and using inserts in the flow of fluid in the absorber tube. In the present study, the parabolic trough is constructed of a mild steel sheet with a receiver made of copper positioned at the focal point, and water was used as the working fluid. Using a bare tube helical receiver with a 2-cm pitch and a black-coated helical receiver, we measured the temperature variations. The results showed that the maximum absorber temperature occurred on the 21st of June at 13.17 PM after maximum solar radiation, which was 148°C. The higher temperature at this time is due to higher instantaneous solar radiation. Also, the minimum collector receiver temperature recorded was on the 21st of December at 13.12 PM, after maximum solar radiation, which was 91°C.