Phase change temperature adjustment of CH3COONa·3H2O to fabricate composite phase change material for radiant floor heating

Hydrated salts phase change materials (PCMs) have a great potential for use in floor radiant heating considering outstanding cost competitiveness and remarkable energy storage density. However, their inappropriate phase change temperatures and the limited methods for temperature adjustment have hindered their widespread applications. Herein, using the formation of non-eutectic mixture to realize phase change temperature adjustment, a novel composite PCM used in the floor radiant heating was developed based on sodium acetate trihydrate (SAT) as main PCM, glycine as temperature modifier and Na2HPO4·12H2O as nucleating agent. The temperature regulation mechanism was discussed and properties of the composite PCM were investigated. The results showed that glycine could regulate melting temperature of SAT from 48.34 to 58.38 °C, ascribing to the formation of hydrogen bond between them. Thereinto, the mixture containing 12% glycine melted at 48.62 °C with enthalpy of 258.5 J g−1, making it applicable to the floor radiant heating. With the addition of 0.5% Na2HPO4·12H2O, the crystallization behavior of the composite PCM was promoted with a low supercooling degree (3.62 °C). The composite PCM presented a melting temperature of 47.55 °C with enthalpy of 256.5 J g−1, good thermal stability and reliability, indicating that the material can be promisingly engineered into the floor radiant heating.