Experimental Investigation of Freezing and Melting Characteristics of Graphene-Based Phase Change Nanocomposite for Cold Thermal Energy Storage Applications

Abstract

In the present work, the freezing and melting characteristics of water seeded with chemically functionalized graphene nanoplatelets in a vertical cylindrical capsule were experimentally studied. The volume percentage of functionalized graphene nanoplatelets varied from 0.1% to 0.5% with an interval of 0.1%. The stability of the synthesized samples was measured using zeta potential analyzer. The thermal conductivity of the nanocomposite samples was experimentally measured using the transient hot wire method. A ~24% (maximum) increase in the thermal conductivity was observed for the 0.5% volume percentage in the liquid state, while a ~53% enhancement was observed in the solid state. The freezing and melting behavior of water dispersed with graphene nanoplatelets was assessed using a cylindrical stainless steel capsule in a constant temperature bath. The bath temperatures considered for studying the freezing characteristics were −6 °C and −10 °C, while to study the melting characteristics the bath temperature was set as 31 °C and 36 °C. The freezing and melting time decreased for all the test conditions when the volume percentage of GnP increased. The freezing rate was enhanced by ~43% and ~32% for the bath temperatures of −6 °C and −10 °C, respectively, at 0.5 vol % of graphene loading. The melting rate was enhanced by ~42% and ~63% for the bath temperatures of 31 °C and 36 °C, respectively, at 0.5 vol % of graphene loading.

Identification and Mitigation of Shortcomings in Direct and Indirect Liquid Cooling-Based Battery Thermal Management System

“…However, adding nanoparticles having higher thermal conductivities as compared to base fluid could enhance the efficiency of the liquid-cooled BTMS [75]. By adding different concentrations of graphene nanoplatelets (GnP), Sidney et al [76] assessed water's thermal conductivity. They noticed that adding 0.5 vol.% of GnP enhanced the water's thermal conductivity by up to 24%.…”

Geometrical Parameter Effects on Solidification/Melting Processes Using Twin Concentric Helical Coil: Experimental Investigations

“…At 4 • C HTF, f-GNP dispersion reduces nano-PCM SEC by 28%. The performance of a low-capacity energy storage tank filled with nano-PCM-containing spherical capsules was assessed by Sidney et al [19]. The findings showed that by adjusting to the HTF parameters, charging and discharging times were reduced by 18.26% to 22.8%.…”

Solidification of Graphene-Assisted Phase Change Nanocomposites inside a Sphere for Cold Storage Applications

“…The KS1 sensor measures the thermal conductivity with an accuracy of ±5%. Thermal conductivity of the PCM nanocomposites was measured at the solid and liquid states based on the method adopted by Sidney et al [20]. Thermal conductivity measurements were performed at least 10 times at a particular temperature to confirm repeatability.…”

“…In this technique, concentrated nitric acid treatment was adopted to modify the surface of GnPs to increase the number of surface-active sites for electrochemical reactions due to the hydrophobic tendency of GnPs. The number of oxygen/nitrogen-containing functional groups formed on the surface of the graphene increased after acid treatment and thus, it increased the hydrophilicity of GnPs [20]. Moreover, studies on the rheological behavior of the PCM nanocomposites are limited in literature [21].…”

“…Sathishkumar et al [22] studied the solidification of water-based GnP nanocomposite in a spherical capsule and observed that the solidification time was reduced by 25% with 1.2 mass % of GnPs. Sidney et al [20] experimentally analyzed the solidification and melting of water-based GnP composite in a cylindrical container. They used functionalized GnPs instead of using surfactants for improving the thermal stability.…”