Preparation and characterization of myristic acid/expanded graphite composite phase change materials for thermal energy storage

Dongyi Zhou,Jiawei Yuan,Yicai Liu,Yuhong Zhou

doi:10.1038/s41598-020-67849-y

Dongyi Zhou, Jiawei Yuan + Show 2 more

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https://doi.org/10.1038/s41598-020-67849-y

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Journal: Scientific Reports	Publication Date: Jul 2, 2020
Citations: 23	License type: open-access

Affiliation: Shaoyang University, Central South University

Abstract

Myristic acid/expanded graphite (MA/EG) composite phase-change material (CPCM) was prepared by absorbing liquid MA (as the PCM) into EG (as the supporting material). Its chemical structure, microstructure, and thermal properties were characterized and studied. In the MA/EG CPCM, the largest mass content of MA was 93.5% by using the diffusion–exudation circle method for the first time. Fourier transform infrared spectroscopy (FTIR) analysis indicated that the MA and EG were a pure physical mixture of which the structure does not change, and they undergo no chemical reaction. Differential-scanning-calorimetry (DSC) analysis results showed that the melting and freezing temperatures of the MA/EG CPCM were 53.3 and 52.4^{,circ }hbox {C}, respectively, and the melting and freezing latent heats were 189.5 and 187.8 J/g, respectively. After several heat-cycle accelerations, the material still had good thermal-energy-storage effect. MA/EG CPCM thermoconductivity was greatly enhanced after adding EG, and the results of thermal-storage/-release experiments indicated that the thermal-storage and -release ratios of the MA/EG phase-change unit was greatly improved when compared with that of MA. These results indicated that the MA/EG CPCM was a suitable low-temperature thermal-energy-storage material.

Highlights

Myristic acid/expanded graphite (MA/Expanded graphite (EG)) composite phase-change material (CPCM) was prepared by absorbing liquid MA into EG
In consideration of MA as phase change materials (PCMs) and EG as the carrier, and on the basis of the melt-adsorption method, an MA/ EG composite phase-change energy-storage material was prepared with the largest MA quality content of 93.5%
Fourier transform infrared spectroscopy (FTIR) test results indicated that no chemical reaction occurred before and after mixing MA and EG; EG only played the role of absorption, and a physical mixture was obtained

Summary

Introduction

Myristic acid/expanded graphite (MA/EG) composite phase-change material (CPCM) was prepared by absorbing liquid MA (as the PCM) into EG (as the supporting material). MA/EG CPCM thermoconductivity was greatly enhanced after adding EG, and the results of thermal-storage/-release experiments indicated that the thermalstorage and -release ratios of the MA/EG phase-change unit was greatly improved when compared with that of MA These results indicated that the MA/EG CPCM was a suitable low-temperature thermal-energy-storage material. Organic, and composite PCMs have been studied for building-energy efficiency, such as p araffin[12,13], polyhydric alcohols[14,15], inorganic salts[16], and fatty acids[17] In these materials, fatty acids are organic PCM that have attracted more attention due to their large latent heat, nontoxicicity, suitable transformation temperature, noncorrosiveness, low degree of supercooling, good thermal stability, and zero or minimal volume change[18,19]. Expanded graphite (EG) is widely used as a form-stable matrix because of its low density, high thermal conductivity, and multiple pores that can prevent liquid leakage, and sharply enhance the thermal conductivity property of P CMs25,26

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