In the present work, a thermal evaluation and optimisation for the components of a solar water heating system was studied. An implicit graphical method was developed to estimate the optimum Ac and V on the basis of the load requirements as well as maximum system efficiency. This method depends on the temperature of hot water extracted for the load, as well as the annual solar factor. The developed method was applied to estimate the optimum dimensions when a daily quantity of hot water (175 l) at 60°C was extracted. The final results showed that with the given load requirements and a solar factor 70%, the optimum Ac and V were 16 m2 and 700 l, respectively.
