Energy- efficient cementitious mortar containing clay based shape-stable phase change material: Development, characterization and temperature controlling performance

Abstract

The need for buildings to ensure a comfortable thermal environment is increasing, leading to a surge in energy consumption. This study proposes an innovative approach to tackle thermal energy storage challenges in buildings by formulating a unique cementitious mortar containing a shape-stable composite of Saudi Arabian natural clay and methyl stearate phase change material (PCM). The inclusion of natural clay, chosen for its cost-effectiveness and eco-friendliness, addresses the issue of methyl stearate leakage—a common concern with PCM usage. Despite PCM incorporation, the mixture maintains desirable fluidity and consistency, albeit with a slightly reduced dry unit weight and compressive strength. Differential scanning calorimetry analysis defines key characteristics of the resulting shape-stable NC/MS composite PCM, including a melting point of 33.81°C and a latent heat storage capacity of 56.15 J/g. Empirical testing demonstrates the efficacy of the natural clay/PCM composite in temperature moderation. During periods of elevated external temperatures, the NC/PCM specimen effectively lowers room-center temperatures by up to 4°C and sustains a cooler environment compared to the control room for almost 8 hours. Additionally, the composite PCM limits the maximum increase in room center temperature post-sunset to only 2.49°C, showcasing its capability in stabilizing indoor temperatures. This innovative PCM composite responds dynamically to ambient temperature variations, transitioning between solid and liquid states to release stored latent heat, consequently reducing building heating and cooling loads, enhancing energy efficiency. The natural clay/PCM composite presents a promising solution for advancing building thermal energy storage systems, aligning with energy efficiency and sustainable design objectives.