Phase change materials (PCM) are used primarily for energy storage and generation in solar thermal collector systems. Achieving the optimal values indicated for the energy discharge time and the net quantity of energy stored (Qnet) in these materials is crucial for optimizing the efficacy of solar thermal collectors. The MATLAB simulator used in this research was developed using a multi-objective evolutionary method that achieves optimization via deconstruction. The simulation showed that the two objectives are mutually exclusive, hence they cannot be met at the same time. When everything is ideal, Qnet is at its lowest and the amount of time spent in the storage tank is at its maximum. Research into the effects of the input components on the objective functions indicates that under optimal circumstances, the mass of PCM and the mass flow rate of the input water are, respectively, at their smallest and maximum values. This was found by analyzing the effect of the input parameters on the objective functions. Considering the influence of the tube's inner diameter on the aim function of a storage tank, it is instantly clear that the time required to release the energy stored inside the tube increases as the tube's diameter increases. Increases in PCM energy storage are shown when tube width is changed while keeping all other system parameters constant.