Synthesis and thermal energy storage properties of a calcium-based room temperature phase change material for energy storage

In order to obtain a low-cost, high latent heat and thermostable phase change material with a phase change temperature between 18 and 25 °C as a room temperature phase change material, a novel solid–liquid calcium-based composite named as PCM-Ca of 44.6% CaCl2, 6.9% Ca(NO3)2, 1.2% SrCl2 and 47.3% H2O with a phase change temperature of 21.8 °C and latent heat of 155.5 J g−1 was developed. The determination of thermal performances of PCM-Ca indicated that the thermal conductivities in liquid and solid state are of 0.6429 and 0.8256 W m−1 K−1, and the thermal conductivity in the phase change point is 1.2401 W m−1 K−1; the specific heat capacities at the temperature range of 5.5–26.5 °C and 31.5–38.5 °C were fitted as y = 0.0001x4 − 0.0042x3 + 0.0707x2 − 0.4151x + 3.9526 (r = 0.9999) and y = −0.0001x4 + 0.0208x3 − 1.1155x2 + 26.477x + 231.57 (r = 0.9984), respectively. The stability analysis demonstrated that PCM-Ca is stable at the temperatures less than 130 °C, and no phase separation and the obvious supercooling phenomenon were presented after thirty times cycle use. This material PCM-Ca has a potential for energy storage application.