Analysis of spherical cavity receiver of solar concentrator for heat losses

In this paper, analysis of total heat losses has done by constructing an experimental set up of electrically heated spherical cavity receiver of solar concentrator. Hollow spherical cavity receiver of copper material having diameter 385mm and thickness 1.5mm is used in the experimental set up. The numerical analysis has done by using the MATLAB programming. The effect of different opening ratio (0.2, 0.3, 0.4, and 0.5), different cavity inclination angles (0 degrees, 25 degrees, 50 degrees, 75 degrees, and 90 degrees) and different operating temperatures (100 degrees C to 600 degrees C) are studied for total heat losses for spherical cavity receiver. The maximum convective losses are found at 0 degree inclination angle of cavity while the minimum convective losses are found at 90 degree inclination angle of cavity because of decrease in convective zone of air and increase in stagnation zone of air in to the cavity. Conduction and radiation losses are independent of cavity inclination angles. The convective losses are also found to be decrease with decrease in opening ratio from 0.5 to 0.2 for different cavity surface temperatures. Experimental results of spherical cavity receiver are compared with numerical results and good agreement is found between the experimental results and numerical results.