Effect of different additives on freezing characteristics and stability of GnP-aqueous-based PCM for cold thermal storage

The aim of the research work reports the thermal performance of graphene-water-based nanofluid phase change material (NFPCM) with different types of surfactants for a cold thermal storage (CTS) system. The graphene nanoplatelets (GnPs) are dispersed in DI water with the addition of commonly used surfactants, such as cetyltrimethylammonium bromide, sodium dodecylbenzene sulfonate (SDBS), sodium dodecylsulfate (SDS), polysorbate (Tween80), polyvinylpyrrolidone (PVP), and gum arabic (GA). The effect on the stability of different surfactants on the colloidal solution of GnP nanofluids is analyzed by zeta potential and particle size distribution. The average zeta potential values indicate that the SDBS-GnP, SDS-GnP, and GA-GnP combinations have good stability after 72 h. The freezing experiment is performed at - 7 degrees C cooling bath temperature in a spherical container and reveals that the surfactants have a significant influence on the supercooling rate and freezing time. The maximum reduction of 92.16% and 84.20% is observed for GA-GnP and SDBS-GnP in the supercooling rate, respectively. The prepared NFPCM can be incorporated in the CTS system owing to its enhanced thermal transport properties to increase the energy-saving potential. Also, the reduction of supercooling facilitates the chiller to operate at higher temperatures.

Automated summary

This research explores the thermal performance of graphene-water-based nanofluid phase change material (NFPCM) with different surfactants, finding that certain surfactants significantly impact the supercooling rate and freezing time. The study concludes that utilizing specific surfactants can enhance the energy-saving potential of the NFPCM CTS system.