Low-temperature phase-change materials (PCMs) are appealing for small, isothermal thermal energy storage in building envelopes, cold-chain systems, and electronics thermal management. This study compares several organic, inorganic, and composite low-temperature PCMs in an experiment. It looks at how their thermal conductivity, specific heat capacity, phase transition temperatures, latent heat, and cycling stability change with temperature. We used differential scanning calorimetry (DSC), laser flash analysis (LFA), transient plane source (TPS), thermogravimetric analysis (TGA), and long-term thermal cycling rigs to get measurements. We looked examined composites containing conductive fillers (expanded graphite, graphene nanoplatelets) and metal-foam scaffolds, as well as plain materials and microencapsulated formulations. The results demonstrate that pure organic PCMs have high latent heat (120–220 kJ·kg⁻¹) but low thermal conductivity (0.18–0.28 W·m⁻¹·K⁻¹). Hydrated salts, on the other hand, have similar latent heat (150–260 kJ·kg⁻¹) but higher thermal diffusivity and larger supercooling and phase segregation tendencies. Adding 5–15 wt% expanded graphite to the material increased its effective thermal conductivity by 3–8 times, but it also reduced its volumetric storage density by up to 12%. Metal-foam scaffolds made apparent conductivity better while keeping more than 90% of the latent heat after 500 cycles. Supercooling in selected salts was reduced from 18 °C to <4 °C with nucleating agents, but at the expense of modest long-term enthalpy loss. The findings are synthesized into practical recommendations for material selection and modification strategies according to application power-density and durability requirements.
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Zhang, X. (2025) A Study on the Thermal Properties of Low-Temperature Phase-Change Materials. Hong Kong Financial Bulletin, 1(4), 1-6.