Experimental study of phase change materials for thermal storage in the temperature range of 300–400°C

Phase change materials (PCM) based on inorganic salts having a temperature of fusion between 300 and 400°C, were investigated using a lab scale set-up dedicated for studying latent heat storage for concentrating solar thermal power (CSP) technology. This experimental system provides thermal measurements of PCM specimens of about 1000 g under the heating temperature up to 450°C and enables simultaneous investigation of calorimetric properties of the loaded materials and heat transfer effects developed in the thermal storage during the charge and discharge phases. The measurement technique comprised temperature and pressure sensors, a control and data acquisition system and a thermal analysis model used to evaluate the experimental data. Results of the thermochemical tests conducted with a thermal storage medium composed of the ternary eutectic mixture of carbonate salts (34.5% K2CO3–33.4% Na2CO3–32.1% Li2CO3) and Diphyl (synthetic thermal oil, max working temperature 400°C) used as the heat transfer fluid are presented and discussed in this paper