In this paper, the thermal performance of a shallow solar-pond (SSP) under the batch mode of heat extraction has been investigated theoretically and experimentally. A transient mathematical model has been proposed. A computer program,has been developed based on an analytical solution of the energy-balance equations of different elements of the pond. Numerical calculations have been carried out to study the effects of various configurational and operational parameters on the pond's performance. To improve the pond's performance, an outer mirror is hinged outside the pond to increase the amount of solar radiation incident on the pond cover. Optimization of various dimensions of the pond has been carried out. Effects of the pond.'s water-depth X-w wind speed V, the sides' X-s and back X-b insulation thicknesses as well as the height C and width W of the outer mirror have been investigated. The influence of the number of glass covers over the pond during the night have also been studied. Comparisons between experimental and theoretical results showed that good agreement has been achieved. Experiments indicated that the pond could provide 88 1 of hot water at a maximum temperature of 60 degreesC at sunset. The pond can retain hot water till 7.00 a.m. next day at a temperature of 47 degreesC: this is suitable for domestic applications. (C) 2003 Elsevier Ltd. All rights reserved.