Comparison of receivers for solar dish collector system

In this paper, a numerical investigation is performed to study the natural convective heat loss from three types of receivers for a fuzzy focal solar dish concentrator, namely cavity receiver, semi-cavity receiver and modified cavity receiver. The natural convection heat loss from the receivers is estimated by varying the inclination from 0o (cavity aperture facing sideways) to 90 deg. (cavity aperture facing down). The orientation and geometry of the receiver strongly affect the natural convection heat loss. A comparative study is performed to predict the natural convection heat loss from the cavity, semi-cavity and modified cavity receivers. The convection heat loss is high at 0 deg. and decreases monotonically with increase in angle up to 90 deg. in all three cases. The convection heat losses at 0 deg. and 90 deg. inclination of the modified cavity receiver are 26.03% and 25.42% of the convection heat loss of the cavity receiver, respectively. The influence of area ratio (Aw/A1) on the convective heat loss is investigated for the modified cavity receiver, and an optimum Aw/A1 of 8 is found for minimum natural convection heat loss. Among the three receivers, the modified cavity receiver is the preferred receiver for a fuzzy focal solar dish collector system