Experimental investigation of modified magnesite-based composite phase change materials for advanced thermal management in buildings

Abstract

The growing global need for sustainable energy management has accelerated research into efficient thermal energy storage (TES) technologies that can offset intermittent renewable energy sources. Phase change materials (PCMs), particularly organic types, have emerged as promising candidates due to their high latent heat storage capacity and reversible thermal behavior. However, their practical use is still hampered by low thermal conductivity and leakage during phase transitions. This study investigates, for the first time, the use of raw and calcined magnesite as natural, low-cost, and environmentally friendly support matrices for 1-dodecanol PCMs. Natural magnesite (MgCO₃) was thermally converted into magnesium oxide (MgO) through calcination, resulting in a porous structure favorable for PCM encapsulation. Comprehensive characterization using FTIR, XRD, BET, SEM, TGA, and DSC revealed that calcination at 800 °C significantly enhanced the surface area and pore structure, improving both PCM loading and thermal stability. The optimized DO@Mag-800 composite achieved the highest PCM encapsulation ratio of 52%, with a latent heat of fusion of 101.2 kJ/kg at a melting temperature of 16.31 °C and an improved thermal conductivity of 0.702 W/(m.K). Furthermore, DO@Mag-800 composite has also been incorporated into concrete at varying ratios, demonstrating good mechanical strength and thermal regulation capabilities for low-temperature building applications.