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 0 degrees (cavity aperture facing sideways) to 90 degrees (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 degrees and decreases monotonically with increase in angle up to 90 degrees in all three cases. The convection heat losses at 0 degrees and 90 degrees 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 (A(w)/A(1)) on the convective heat loss is investigated for the modified cavity receiver, and an optimum A(w)/A(1) 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. (c) 2007 Elsevier Ltd. All rights reserved.