Numerical investigation of modified conical cavity receiver with different heat transfer fluids

Abstract

ABSTRACT The parabolic dish system is viable for meeting high-temperature requirements by harnessing solar energy. The receiver has a significant impact on the thermal efficiency of the solar parabolic dish system. Historically, the cavity receiver (CR) has been preferred over other receivers due to its reduced heat loss. Over the past two decades, numerous CR geometries have been developed in an effort to further improve thermal performance. The influence of several heat transfer fluids, including water, thermal oil, thermal oil/Al2O3 nanofluid, and thermal oil/MWCNT nanofluid, was investigated in this research using a three-dimensional numerical simulation on a modified conical cavity receiver (MCCR). Heat transfer fluids are considered to flow through copper tubes in a MCCR. The temperature contours, the inlet and outlet temperatures were numerically predicted. The experimental results were used to validate the numerical conclusions for the outlet temperature of the heat transfer fluid (water). According to the numerical results, Al2O3/thermal oil nanofluid attained the maximum exit temperatures (83.8°C to 95.1°C) and exergy efficiency (7.68%). The average thermal efficiency of systems with working fluids MWCNT/Thermal oil, Thermal oil, and Al2O3/Thermal oil was found to be 15.3%, 21.8%, and 28.2% greater than water, respectively. For the given solar radiation, the thermal oil/Al2O3 nanofluid achieved the highest average thermal efficiency of 59%. Whereas the average thermal efficiency of thermal oil and thermal oil/MWCNT was found to be 56%, and 53%, respectively. In addition, a correlation for the Nusselt number was developed in terms of the Prandtl number and the Reynolds number.