关键词: CaCl₂·6H₂O, SiO₂气凝胶, 相变材料, 泡沫混凝土, 储热隔热

Abstract:

Phase change concrete materials are widely used in the field of building insulation and building energy conservation.CaCl₂·6H₂O/SiO₂ aerogel composite phase change materials were prepared by physical mixing method with SiO₂ aerogel as carrier，CaCl₂·6H₂O as phase change material and SrCl₂·6H₂O as nucleating agent.The thermal storage and insulation properties and thermal reliability of the composite phase change materials were evaluated.The CaCl₂·6H₂O/SiO₂ aerogel composite phase change foam concrete was prepared by mixing silicate cement，foaming agent，thickener，water reducing agent，composite phase change material and water according to a certain mixing ratio.The effects of CaCl₂·6H₂O/SiO₂ aerogel doping amount on the mechanical properties and heat storage and heat resistance properties of composite phase change foam concrete were analyzed.The results showed that compared with CaCl₂·6H₂O phase change material，CaCl₂·6H₂O/SiO₂ aerogel composite phase change material exhibited excellent heat storage and insulation performance and thermal reliability.When the mass fraction of CaCl₂·6H₂O was 70%，the CaCl₂·6H₂O/SiO₂ aerogel composite phase change material did not leak.The thermal conductivity，phase change temperature，phase change enthalpy and supercooling degree were 0.095 8 W/（m·K），27.32 ℃，113.5 J/g and 1.5 ℃，respectively.The CaCl₂·6H₂O/SiO₂ aerogel composite phase change material had little change in phase change temperature and phase change enthalpy after 100 thermal cycles，and the supercooling degree was reduced from 1.5 ℃ to 0.7 ℃，which had excellent thermal reliability.When the doping amount of CaCl₂·6H₂O/SiO₂ aerogel was 20%，the phase change temperature and enthalpy of phase change foam concrete were 21.68 ℃ and 32.3 J/g，respectively.The thermal conductivity，specific heat capacity，heat storage coefficient and thermal inertia were 9.17%，69.98%，52.05% and 35.70% higher than those of ordinary foam concrete，respectively.Compared with ordinary foam concrete，phase change foam concrete had good heat storage，heat resistance and thermal conductivity.The research provided a new idea for the development of thermal insulation concrete.

Key words: CaCl₂·6H₂O, SiO₂ aerogel, phase change materials, foam concrete, heat storage and insulation