Study and Characterization of a Spherical Solar Collector. Part II: Comparative Analysis with Flat-Plate Devices

Abstract

The paper analyses the performance of a spherical solar collector compared to the efficiency of a flat-plate solar collector, which is the type of solar collector that does not use a tracking system in collecting solar radiation for energy conversion. Spherical solar collector benefits from a constant value of the angle of incidence, which optimizes the solar radiation that strikes the absorber of the solar device and maximizes the energy collection. Besides, the spherical geometry has a larger area for equal dimensions, width, and length. The combined effect of a larger surface and a higher value of the effective solar radiation onto the surface of the absorber increases the energy collection and the performance of the solar device. We developed a theoretical analysis to obtain the algorithm to determine the collected solar energy, which increases when using the spherical solar collector. A simulation runs to calculate the predicted values. We developed experimental tests in a spherical solar collector of 1.05 m in diameter, and in a flat-plate solar collector of 1.94 m × 1.025 m. to validate the simulation. The comparative analysis shows that a spherical solar collector generates more energy than a flat-plate one of the same absorbing surface by a factor of 2.09, and 7.75 times more if the width and height of the flat-plate collector equals the diameter of the spherical one.