HEAT-ACCUMULATING COMPOSITION BASED ON A EUTECTIC MIXTURE OF SODIUM THIOSULPHATE PENTAHYDRATE AND SODIUM ACETATE TRIHYDRATE Russian patent published in 2022 - IPC C09K5/06 

FIELD: chemistry.

SUBSTANCE: invention relates to heat-accumulating materials capable of storing and emitting heat due to phase transition processes, applicable in heating systems in the temperature range of 30 to 45 °C. Proposed is a heat-accumulating composition based on a eutectic mixture of sodium thiosulphate pentahydrate and sodium acetate trihydrate, consisting of 30 wt.% sodium acetate trihydrate CH₃COONa·3H₂O, 70 wt.% sodium thiosulphate pentahydrate Na₂S₂O₃·5H₂O with additives in the form of 1 wt.% expanded graphite (EG) and 2 wt.% polyvinyl alcohol (PVA), characterised by phase transition temperatures during melting and crystallisation, supercooling not above 3 °C, and accumulation time ensuring the operability of the material as a heat-accumulating composition between 30 and 45 °C, and produced by melting a eutectic mixture of sodium thiosulphate pentahydrate and sodium acetate trihydrate for 20 minutes while continuously stirring until fully melted, followed by adding expanded graphite, stirring for 20 minutes and adding polyvinyl alcohol, after which, mixing is continued for one more hour with temperature control at 60 °C.

EFFECT: proposed phase transition heat-accumulating composition is characterised by absent phase segregation, supercooling reduced to 2.8 °C, and a reached phase transition temperature of 41.8 °C.

1 cl, 7 dwg, 3 tbl