Preparation and characterization of solid-state neopentyl glycol / expanded graphite micro composite for thermal energy storage applications

Abstract

Phase Change Materials (PCM) are used in the thermal energy storage system (TESS) for their heat absorption capacity at a constant temperature. Among the various phase change materials (PCM), neopentyl glycol (NPG) with its structural properties undergo solid-state crystal transformations (∼41 °C) which absorb and release substantial latent heat (131 kJ/kg). The major advantage of such PCM in TESS is that this PCM can be used without concern about the liquid leakage and massive volumetric expansion during phase transitions. In the current work, the micro composite of NPG and expanded graphite (EG) were successfully synthesized and characterized using the one-step technique. NPG is saturated into the expanded graphite with different weight ratios in order to increase the thermal performance of PCM for thermal energy storage (TES) application. NPG was uniformly mixed with the matrix of the expanded graphite (EG). Further, the morphological and structural characterization was carried out to analyze the formation of micro composite (NPG/EG). The Field effect-scanning electron microscopy (FESEM), Fourier Transformation Infrared Spectroscopy, Raman profile and DSC results revealed the formation of shape stabilized NPG/EG micro composites. Also, the thermal conductivity of the micro composite showed the enhancement of up to 10 times as compared to the pure NPG. This micro composite can be well suitable for thermal energy storage.