A numerical study of a charging process of thermal energy storage (TES) system with solar tower receiver was investigated under real environmental condition of Jeddah area, where molten salt was considered as the working fluid of the TES tank. Incident heat flux data which was computed from beam radiation data of Jeddah area with ray tracing technique is used as an input power to the TES system. The Cranck–Nicolson numerical technique is used to model the transient temperature profile of the TES system, while the classic empirical equation is incorporated in the numerical modelling to consider the heat loss from the tank. Hourly variation in efficiency of the solar tower receiver, the transient temperature profile of the TES at different position of the tank, the transient profile for the average temperature of the TES system, and the transient energy storage profile of the storage tank was investigated in this study.