Thermodynamic properties of sodium sulfate-based complex phase-change cool storage system

Aim To investigate and prepare a new material for cool storage of air conditioner in temperature range of 5-10 C. Methods The variation of phase-transition temperature with the composition of the cool storage system in which Na2S04 · 10H2O was selected as the main component was determined, and suitable formulas were defined. Means for preventing supercooling and segregation were studied. Results An eutectic salt hydrate composition comprising 80% of Na2S04 · 10H2O, 2%-8% of KC1, 5%-10%NH4C1 and 1%-5%(NH 4)2SO4 has a melting point of 9-10 C. Conclusion Na2SO4 · 10H2O's transition temperature was reduced by adding salts - KC1, NH4C1, (NH 4)2SO4 or NaCl. Adding a nucleating agent and a thickening agent can inhibit supercooling and eliminate segregation.