Eliminating supercooling and accelerating crystallization of sodium acetate trihydrate by bubbling with seeding for low-temperature thermal energy storage

The typical inorganic hydrated salt phase change material SAT is recommended as a potential medium ideal for long-term thermal energy storage due to its stable supercooling. The crystallization-triggering approach to activate the release of latent heat requires further investigation. The present work mainly deals with the bubbling-triggered crystallization of SAT. The experimental results showed that bubbling can trigger the crystallization of SAT in the cooling temperature range of 10–25 °C. Unfortunately, it has the issue of poor repeatability during crystallization. Furthermore, it was found that a coupled technology of bubbling with seeding can further shorten the crystallization duration, thus accelerating the crystallization process. Under constant cooling, the degree of subcooling is reduced to as low as 2.2 °C, and the crystallization time is shortened by 4 min at a typical cooling temperature of 25 °C. The crystal structure of bubbling-triggered crystallization was also involved, and the experiments show that there is no significant change in the crystal structure with bubbling, indicated by the lattice constant of the SAT crystal. Therefore, such a coupled technology is recommended for SAT crystallization in long-term latent heat storage scenarios. The obtained results are helpful for crystallization triggering and supercooling reduction in the field of long-term latent heat storage.