The study investigates using edible oils (ostrich, mutton, beef, coconut) as natural phase change materials for solar energy absorption and storage. Exposed to 900 W/m2 direct radiation by a solar simulator, these materials harness captured energy at a specific depth to generate electricity through a thermoelectric device. The experimental results showed that coconut oil exhibits the highest thermal energy storage efficiency among others, measuring at 39 %, while mutton tallow shows the lowest performance at 16.59 %. Additionally, the performance of a system employing coconut oil as the best material, in combination with iron oxide nanoparticles and carbonized sawdust (CS) was experimentally evaluated at different mass fractions (0.3 %, 0.6 %, and 0.9 %) to enhance thermal conductivity and sunlight absorption. The carbonized sawdust and its nanoparticles increased the thermal energy storage efficiency of the system by 62 % and 53 %, respectively. Moreover, the stored exergy by the phase change materials indicates that coconut oil and beef tallow had the highest and lowest exergy efficiencies of 6.3 % and 3.3 %, respectively. The combination of coconut oil with iron oxide nanoparticles and carbonized sawdust leads to 10 % and 7.9 % increased exergy efficiencies respectively.

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