Synthesis, characterization and determination of thermal properties of shape stabilized n-pentadecane based composite phase change materials including graphitic carbon nitride/alumina fillers for latent heat storage applications

Abstract

Recently, Phase Change Materials (PCMs) has attracted significant interest for thermal energy storage (TES), which is a rational and convenient energy storage method. In the present work, new composite PCMs were prepared by performing easy impregnation process in which n-pentadecane was selected as PCM. For this, emulsion templated porous polymer composites were synthesized and employed as the frameworks to obtain new composite PCMs. To improve the heat transfer characteristics, the support matrices were prepared by loading of 1 wt% thermal conduction enhancer fillers namely, graphitic carbon nitride (g-C3N4), graphitic carbon nitride/alumina (g-C3N4/Al2O3) and alumina (Al2O3). The chemical structure, thermal stability and specific surface area characteristics of the frameworks were examined by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG) and Brunauer-Emmet-Teller (BET) surface area analyses. Furthermore, the morphology and distribution of the fillers were explored with Scanning Electron Microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Additionally, improvements in the thermal conduction properties of the composite matrices were determined through the tests performed based on the T-history method. Moreover, the examinations on the thermal properties of the obtained composite PCMs were carried out using Differential Scanning Calorimetry (DSC). It was found that the reductions in supercooling temperatures (Delta T) were observed for the synthesized composite PCMs compared to degree of supercooling of pristine n-pentadecane. According to the obtained results, the synthesized composite PCMs can be employed in the cold thermal energy storage (TES) applications considering their appropriate properties and favorable TES capacities between 79.49 kJ/kg and 121.50 kJ/kg.