Optimization of supercooling, thermal conductivity, photothermal conversion, and phase change temperature of sodium acetate trihydrate for thermal energy storage applications

The demand for space heating and domestic hot water has caused an increase in building-energy consumption. Thermal energy storage systems can effectively solve the mismatch between heat supply and demand. Phase change materials (PCMs) can be served as the thermal storage media for thermal energy storage systems. In this study, the tailor-made sodium acetate trihydrate (SAT, a kind of PCM) was developed. Multi-wall carbon nanotubes (MWCNTs) was employed as the nucleation agent of SAT, meanwhile other carbon-based materials, including carbon fiber (CF), expanded graphite (EG), and graphene nanoplates (GNPs), were synergistically used as thermal conductivity and photothermal conversion enhancers. Ammonium chloride (NH4Cl) was innovatively adopted as a phase change temperature regulator for SAT. The results showed that the supercooling degree of SAT decreased to 0.9 ? with the presence of MWCNTs. The thermal conductivity of SAT improved by 54.9%, and the photothermal conversion efficiency increased to 89.3% after incorporating GNPs into the SAT/MWCNTs composite. Furthermore, phase change temperature of the SAT/MWCNTs composite, ranged from 57.5 ? to 45.1 ?, could be prepared by adjusting NH4Cl contents for satisfying different application scenarios. The results indicate that the prepared SAT composites can be potentially used in different thermal energy storage systems. (c) 2022 Published by Elsevier Ltd.

Automated summary

Tailor-made sodium acetate trihydrate (SAT), as a phase change material (PCM), was developed in this study. The addition of multi-wall carbon nanotubes (MWCNTs) as nucleation agents and other carbon-based materials as thermal conductivity and photothermal conversion enhancers improved the thermal conductivity and photothermal conversion efficiency of SAT. Furthermore, by adjusting the content of ammonium chloride (NH4Cl), the phase change temperature of the SAT/MWCNTs composite could be varied to satisfy different application scenarios.