To bridge the gap between supply and utilization of solar thermal energy storage (TES) systems are developed. The TES systems using both sensible and latent heat storage systems are gaining much attention because of its advantages like high energy storage in a unit volume and its isothermal behavior during the charging and discharging processes. The experimental investigation is done to analyze the effect of phase change material (PCM) capsule material on the performance of TES system during charging and discharging processes. The PCM capsules are spherical in shape and its outer diameter is 68mm. In the process of investigation the spherical capsules are made using three different materials viz. i) High Density Poly Ethylene (HDPE), ii) Aluminum (Al) and iii) Mild Steel (MS). The PCM material used in the experiments is paraffin (type II). The TES system is coupled with flat plate solar collector. The experimental investigation showed that the charging and recovery of storage energy is less affected by the spherical capsules material. The variables like charging time and discharging quantity are varied around 5% for the different capsule materials. Even though Aluminum thermal conductivity is much higher than HDPE and mild steel, its influence on performance of TES system is very less due to very high internal heat resistance of PCM material stored in the spherical capsules.