Enhancing thermal performance of parabolic dish collectors: Impact of insulation and flow rates on a conical receiver

This study investigates the thermal performance of a conical cavity receiver (CR) integrated within a parabolic dish collector (PDC), with a focus on insulation methods to reduce heat loss. A satellite dish was modified into a solar reflector, which was used as a PDC and fitted with a two-axis solar tracking system; Additionally, the reflector was equipped with glass mirrors that had a reflectivity of 83 $\%$. The receiver was tested under four different insulation scenarios: no cover, single-layer glass cover, double-glass evacuated cover, and double-glass evacuated cover with an additional layer of glass wool insulation. The glass wool cover, combined with a double-glass evacuated cover, achieved the highest system performance, with maximum temperature of 227 $°C$ and energy and exergy efficiencies of 66.4 $\%$ and 16.9 $\%$, respectively. Additionally, increasing the flow rate from 100 $mL/\min$ to 150 $mL/\min$ enhanced the overall efficiency, reaching a peak value of 57.7 $\%$. A solar receiver that incorporates efficient insulation methods, as verified in this study, can significantly improve the efficiency of cost-effective solar collectors by applying the principles learnt. This enables solar concentrators to be significantly more affordable without compromising their efficiency, as demonstrated by the findings in this study.