This paper deals with the thermodynamic optimization of a solar driven adsorption refrigeration system. An externally irreversible but internally endoreversible model has been employed to analyse the optimum conditions for which the maximum refrigeration effect can be achieved. It is seen that a chiller attains its highest capacity if the thermal conductances of the heat exchangers are distributed properly. It is also seen that half of the total thermal conductances are allocated between the condenser and adsorber heat exchangers that release heat to the external ambient. The coefficient of performance (COP) for the optimum conditions is also presented. It is observed that the COPopt increases in parallel with the dimensionless collector stagnation temperature, tau (st), as well as with the increase of the required refrigeration space temperature, tau (L), while the COPopt decreases as the ratio of collector size to the cumulative size of all four heat exchangers, B, increases. (C) 2000 Elsevier Science Ltd. All rights reserved.