Solar energy as free and abundant energy is considered among the renewable energy that can replace disappearing fossil fuels. Many solar power systems can be used to capture this energy, but the majority does not have the ability to store this energy in different weather and time conditions. Therefore, salinity gradient solar ponds used in the present work can overcome this issue by simultaneously capturing and storing solar energy. A solar pond is being built at Annaba. In this present work we consider two identical solar ponds subjected to the same solar radiations during a period of 28 days, and exposed to the same climatic conditions, initial and at the limits. in the first pond, nanoparticles of conductive metal, namely copper, are injected with a concentration of $0.09\%$, while the second pond does not contain any nanoparticles. a comparative study was carried out on the temperature profile in the two solar ponds mentioned above to see the influence of nanoparticles on the thermal performance of the solar pond. The mathematical model adopted in this work is based on the equation of heat conduction in two dimensions with an external source of energy to the system. The method of finite differences with ADI scheme was used to determine the temperature distribution in two different directions according to the horizontal axis ox and to the vertical axis OZ representing the depth. An average temperature and insolation values for the last ten years were obtained using the data provided by Annaba saline station. Finally, a comprehensive study was carried out in order to highlight the convergence, consistency and stability properties of the discrete model representing the solar pond.