In this paper, the opto-geometric performance of fixed-focus solar concentrators (FFSCs), namely, the high temperature concentrator (HTC), the Scheffler concentrator and the Scheffler-type solar concentrator (STSC), is analysed. The goal of this study is to determine the behaviours of FFSCs as a function of their dimensions and to compare the results to the results of parabolic dish (PD) solar concentrators. An algorithm based on opto-geometric models of these concentrators was developed, and numerical calculations were performed for each type in a range of thermal power of 1-50 kW. The numerical results indicate that FFSCs require a reflector with a diameter 45% larger than the diameter of a PD concentrator and increase the diameter of the solar image at the receiver by 350% compared with a PD concentrator. The increase in the diameter of the solar image by the fixed receiver in the FFSC produces a lower concentration. For thermal demands of less than 10 kW, FFSCs do not have significantly large dimensions. The proposed algorithm can be employed to evaluate the potential use of FFSCs and an FFSC instead of a PD concentrator because of the operational advantages of the fixed receivers of the different types. (C) 2016 Elsevier Ltd. All rights reserved.