ISSN Online: 2688-7231
ISBN Online: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
Performance Investigations of the Energy Discharge Characteristics of High-temperature Phase Change Material Capsules
Thermal energy storage using phase change material (PCM) capsules is a prevalent method used in high-temperature applications such as steam generation and concentrated solar power. However, the research works on the development of latent heat storage (LHS) PCM encapsulations are limited. In the present study, experimental and numerical investigations of high-temperature cylindrical encapsulations filled with sodium nitrate were conducted using air as the heat transfer fluid. A modification of the cylindrical capsule known as the annular capsule is proposed to improve the heat transfer characteristics inside the PCM by providing a heat transfer surface at the center of the capsule. Experimental investigations were conducted on a high-temperature (723 K) test facility to determine the discharging characteristics of both the capsule designs in the temperature range between 603 K and 473 K. A 2D axisymmetric numerical model is developed and validated with the results obtained from the experiments. The performances of both the basic and annular capsules are compared and it is observed that the discharging time reduced by 24% for the annular capsule. The heat transfer enhancement occurs due to an increase in the contact surface area and the improvement in flow characteristics of the air.