Effects of the inclination angle of planar encapsulated PCM in freezing and melting kinetics

Experiments and simulations have been used to study the freezing and melting kinetics of a single capsule containing a phase change material (PCM) for thermal energy storage. A commercial encapsulated PCM (EPCM) has been selected, with a melting/freezing temperature of approximately −3 °C, and the effect of the inclination angle on the phase change kinetics has been studied. Experimentally, the freezing and melting times have been determined using a thermocouple located in the center of the capsule. The results show a non-monotonic trend in the freezing time with the inclination angle, with a maximum at 45°, both in the simulations and experiments. For the melting, a decreasing trend is observed in the simulations, which cannot be verified experimentally due to the measurement errors. Additionally, the simulations indicate that the misallocation of the internal probe within the nodule center can affect the results only marginally. Finally, the simulations show that the loose material within the capsule slows down the freezing, and increases the effect of the inclination angle.