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Development of spherical α-Al2O3-based composite phase change materials (PCMs) and its utilization in thermal storage building materials

Miao, Wenjuan, Wang, Yingbin, Li, Xiangguo, Gan, Shulie, Lv, Yang, Liu, Zhuolin
Thermochimica acta 2019 v.676 pp. 177-185
aluminum oxide, cement, construction materials, differential scanning calorimetry, energy conservation, energy efficiency, heat, mechanical properties, phase transition, scanning electron microscopy, silica, thermography, thermogravimetry
The building energy consumption is increasing constantly with the rapid development of global economy. Integrating PCMs into cementitious materials has great potential in improving building energy efficiency through thermal regulation. In this study, a novel α-Al2O3 spherical skeleton is fabricated to create a new kind of form stable phase-change material (FSPCM). Then its surface is coated with a silica layer to prevent the leakage of the inner phase-change materials and intensify the binding with cement. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and leakage test demonstrate its spherical structure, high thermal storage capacity and stability, and excellent leakproof performance. Further, the novel FSPCM is added into Portland cement at the weight ratio of 20% to prepare the thermal storage cement-based materials (TSCM). The properties of TSCM are evaluated by compressive test, calorimetry, SEM and infrared thermography. The results show that TSCM presents satisfying mechanical property (47.1 MPa at 28 d), less hydration heat, good workability (200 mm for the fluidity) and superior thermos-regulating ability (maximum ΔT = 10.5 K). From this work, it can be inferred that the designed TSCM with 20 wt% of FSPCM is a promising candidate for building energy conservation.