This paper presents the development, experimental testing, and numerical investigation of water-based phase change material (PCM) thermal energy storage (TES) using the shell-and-tube design with different tube layouts including single serpentine, double serpentine, and spiral. Sodium acetate trihydrate (SAT) with a melting temperature of 58 ��C was used as the storage medium. The major contribution of this study is the sensitivity analysis and performance comparison of the shell-and-tube PCM TES units with different tube layouts. A quasi-three-dimensional dynamic model of the PCM TES unit was developed and used to predict the performance of the TES unit under different design and operating conditions, which was validated against the experimental data. A global sensitivity analysis was implemented to quantify the influence of the design parameters on the performance of the PCM TES unit. The results showed that the inlet water temperature was the most influential parameter, followed by the tube length, water flow rate, tube layout, and PCM thermal conductivity. The PCM TES module with the spiral tube layout and the double serpentine tube layout generally outperformed that with the single serpentine tube layout. The time required to charge the PCM to a liquid fraction of 0.95 was reduced by 16.0% if changing the tube layout from single serpentine to spiral and when the tube length was 4,055 mm. The findings obtained from this study could be potentially used to guide and facilitate the design of the shell-and-tube PCM TES units.