This paper presents the results of optimization analyses of four main sizing-parameters for stationary flat-surfaces under various load profiles in four different locations in Libya (Tripoli, Lat. = 32.87 degrees N; Benghazi, Lat. = 32.10 degrees N; Sebha, Lat. = 27.02 degrees N; Kufra, Lat. = 24.22 degrees N). The study is aimed at matching the load profile with the energy available from the solar collection sub-system. The parameters optimized in this study are tilt angle of the solar flat surface (beta), the design time (T-D), the collector array capacity (C-A), and the relative storage capacity (C-S). (C) 1999 Published by Elsevier Science Ltd. All rights reserved.