Thermal Property Testing of Nitrate Thermal Storage Salts in the Solid-Phase

Implementation of molten salt compounds as the heat transfer fluid and energy storage medium provides specific benefits to energy collection and conversion. Nitrate salts have been identified as a strong candidate for energy transfer and storage and have been demonstrated for use in these applications over time. As nitrate salts have solidification temperatures above ambient, concern for recovery from salt freezing events has instigated efforts to understand and predict this behavior. Accurate information of salt property behavior in the solid-phase is necessary for understanding recovery from a freeze event as well as for phase change thermal energy storage applications. Thermal properties for three representative salts (that span the range of melting temperatures from approximately 90–221 °C), have been obtained. These properties include specific heat, coefficient of thermal expansion, and thermal conductivity. Specific heat and thermal conductivity were measured using differential scanning calorimetry.