Enhanced heat transfer behaviour of a water-based graphene oxide PCM composite for cold energy storage systems

Highly concentrated graphene oxide-based phase change material (PCM) composite is investigated for its heat transport behaviour when applied in a cold storage system. Optimizing thermal properties and behaviors during phase change is crucial to mitigate the bottlenecks of poor thermal conductivity resulting in the thermal resistance of a proper and faster heat transfer during solidification. The current study considers an efficient way to enhance the bottlenecks by synthesizing a highly concentrated GO aqueous solution. Differential scanning calorimetry and scanning electron microscopy are conducted to characterize the thermal and morphological properties of the composite matrix while to address the stability issue associated with solid-liquid change, variation of rheological properties for differently concentrated GO-PCM composites with temperature and shear rate is conducted. A non-Newtonian nature is obtained with lower shear rates, while GO exhibits a Newtonian behaviour under higher shear rates. Viscosities for highly concentrated PCM composites are found to be temperature-sensitive. In addition, dependency upon the crucial operating factor during the phase change process is discussed. Operating factors like heat transfer fluid (HTF) inlet temperature and its mass flow rate are investigated during the time-wise temperature evolution in the PCM composite. Inlet HTF temperature is found as a key parameter to shorten the process by 33 % compared to the mere effect obtained while increasing the mass flow rate. The addition of GO particles is found to be beneficial after the latent heat gets released, which helps shorten the total solidification time by 42 %. However, a decrease in the total storage capacity is found when compared with DI water. • A 42 % decrease in total solidification time is achieved with the GO-PCM composite. • GO exhibits non-Newtonian and Newtonian nature at low and high shear rates. • A significant effect of HTF inlet temperature is found on GO-PCM solidification. • A 27 % reduction in latent heat with 42 % faster solidification time is observed.