The Effect of Static Magnetic Field on the Behavior of Phase Change Material

Abstract

The rate and reliability of thermal energy release in Phase Change Materials (PCMs) remain critical challenges in energy storage systems, particularly due to their typical reliance on temperature variation to trigger phase transitions. This study explores a novel, non-thermal pathway for influencing PCM behavior through the application of static magnetic fields. The thermal responses of four PCMs—octadecane, heptadecane, decanoic acid, and calcium chloride hexahydrate (CaCl₂·6H₂O) with and without the addition of NaCl as a nucleating agent —were investigated under magnetic field strengths of 91.3 mT, 149 mT, and 240 mT. Results show that PCMs with lower Prandtl numbers or higher electrical conductivity are more sensitive to magnetic field strength, exhibiting reduced heat flux and extended melting durations due to the decrease in convective velocity. Moreover, supercooling in CaCl₂·6H₂O was suppressed when 1.055% NaCl was combined with magnetic field exposure—a concentration that, without magnetism, failed to initiate crystallization. This shows that magnetism can complement or even enhance the effect of nucleators, offering a new route to trigger or control phase transitions. By enabling finer control over the timing and rate of thermal energy release, this work opens new possibilities for designing smarter, more responsive PCM-based storage systems. The findings are particularly impactful for applications involving salt hydrates, where supercooling is a persistent issue. This dual physical–chemical approach has the potential to significantly improve the efficiency, stability, and tunability of energy systems in buildings and renewable energy systems.