Ageing Stability of Sodium Acetate Trihydrate with and Without Additives for Seasonal Heat Storage
Abstract
Sodium acetate trihydrate is a promising phase change material used for seasonal heat storage because it can supercool in a stable way down to ambient temperature. One challenge of this material is that it might suffer from phase separation resulting in a low utilization of the heat of fusion. Adding extra water or thickening additive has been suggested as an effective way to reduce the phase separation problem and thereby maximize the heat content of the sodium acetate trihydrate. Investigations of phase separation and heat content of supercooled sodium acetate trihydrate with and without extra water and additives were carried out under different test conditions. It was found that sodium acetate water mixtures with water contents lower than or equal to 42% would suffer from phase separation for the height of heat storage up to 8 cm. The heat content of sodium acetate trihydrate will be decreased by adding extra water. Sodium acetate trihydrate with Carboxy-Methyl Cellulose and Xanthan Gum as additives are promising heat storage materials with high heat contents and ageing stability.
Keywords
Sodium acetate trihydrate, Phase change material, Ageing stability, Phase separation