Fabrication and performance analysis of CaCl2•6H2O-NH4Cl-TiO2/EP as energy storage composite materials for building thermal management in continental climates

Integrating inorganic phase change materials into walls effectively enhances thermal comfort and energy efficiency for building management in continental climates. A strategy is proposed to encapsulate CaCl2 center dot 6H2ONH4Cl-TiO2 composite phase change material with expanded perlite to develop an innovative composite thermal energy storage material that offers flexible temperature adjustment. By adding NH4Cl and TiO2, the subcooling degree decreases from 18.7 degrees C to 1.3 degrees C, the phase change temperature adjusts to 22.34 degrees C, and the latent heat increases to 193.2 J/g. The synergistic effect of NH4Cl and TiO2 reduces the phase change temperature, making it more suitable for continental climates, and increases the latent heat by 3.21 %. The expanded perlite creates a shape stable phase change material, reducing thermal conductivity by 79.93 % and maintaining stability after 500 cycles. Additionally, we encapsulated the CaCl2 center dot 6H2O-NH4Cl-TiO2/expanded perlite in polycarbonate boards to create phase change insulation boards, and constructed a building model to evaluate their performance. The results indicate that CaCl2 center dot 6H2O-NH4Cl-TiO2/expanded perlite boards have significant potential to improve indoor thermal environments and enhance building energy efficiency, particularly in continental climate. In summer, the maximum inside surface temperature is 0.6 degrees C lower, with a 600 s delay, while in winter, the minimum temperature is 1.3 degrees C higher, with a 980 s delay, compared to expanded perlite boards. Furthermore, it costs about 18 % less than expanded perlite board, making it highly promising for building applications.