A novel calcium chloride hexahydrate-based deep eutectic solvent as a phase change materials

• A new type III DESs was prepared from choline chloride and calcium chloride hexahydrate.
• Fundamental physico-chemical properties of prepared DESs were reported.
• The prepared DESs were investigated as potential PCMs for building applications.
• Strontium chloride hexahydrate and fumed silica were employed as nucleating agent and thickening agent, respectively.

Deep eutectic solvents (DESs) are gaining interest in various applications due to their tuneable properties and affordable preparation cost. Developing low cost new DESs is vital for some potential industrial applications. This work introduces a new type III DESs based on choline chloride as a quaternary ammonium salt (QAS) and calcium chloride hexahydrate as a hydrated salt. The prepared DESs were characterized by measuring some of their important physical and chemical properties. Furthermore, the applicability of the new DESs as a possible phase change material (PCM) that can be used for building applications was investigated. The experimental results manifested that the DESs in the molar ratios of 1:6 and 1:8 (QAS: hydrated salt) have the potential to be utilized as PCMs in building applications with large latent heat (127.2–135.2 kJ Kg−1) and suitable phase change temperature (20.65–23.05 °C), However, they suffered from supercooling and phase segregation. In order to overcome these problems, 2 wt% of SrCI2·6H2O as nucleating agent and fumed silica as thickener were used during the 100 thermal cycling test. The cycling results showed the degree of supercooling of the DESs was significantly reduced and the phase change temperatures of the DESs remained unchanged.