▎ 摘　　要

Cold thermal energy storage (CTES) is paramount for energy management in large building air-conditioning systems using phase change materials. In this study, the thermal transport performance of DI water is enhanced with a natural gum as a nucleating agent (gum acacia (GA)) and a high conductive nanomaterial (graphene nanoplatelets (GnPs)). The nanofluid phase change materials (NFPCMs) are prepared with different mass concentrations viz. 0.25%, 0.50%, 0.75%, and 1.00% of GnPs by a two-step synthesis method. The zeta potential, UV-visible spectrophotometry, and visual inspection methods are used to analyze the stability of NFPCM over time. The phase change enthalpy is lowered by 7.72% and 15.26% for 1.00% GnPs seeding into DI water at a heating rate of 5 Kmin(-1) during heating and cooling, respectively. Thermal conductivity of NFPCM shows maximum augmentation of 10.8% (25 degrees C) and 54.4% (- 5 degrees C) owing to its highly conductive specific surface area of stable GnPs. The temperature-time history of NFPCMs is investigated during freezing experimentation in a spherical encapsulation at a surrounding bath temperature of - 7 degrees C. GA has a major influence on the degree of supercooling, as it causes a 47.6% drop in DI water and eliminates it at a higher mass concentration (1.00%) of GnP-NFPCM. The maximum freezing rate is reduced by 27.1% with a higher mass concentration of NFPCM compared to pure PCM. Furthermore, a significant energy-saving potential of 4 to 6% is revealed for GA-NFPCM, which shows tremendous promise for developing energy-effective thermal management with an accelerated mode of charging.