Tetradecanol/expanded graphite composite form-stable phase change material for thermal energy storage

• Published in: Solar energy materials and solar cells Vol. 127; pp. 122 - 128
• Main Authors: ZENG, Ju-Lan, JUAN GAN, ZHU, Fu-Rong, YU, Sai-Bo, XIAO, Zhong-Liang, YAN, Wen-Pei, LING ZHU, LIU, Zhen-Qiang, SUN, Li-Xian, ZHONG CAO
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01.08.2014
• Subjects: Applied sciences; Electrical engineering. Electrical power engineering; Energy; Energy. Thermal use of fuels; Enthalpy; Exact sciences and technology; Graphite; Heat transfer; Materials; Microwaves; Phase change materials; Storage capacity; Thermal conductivity; Thermal energy; Transport and storage of energy; Natural graphite; Expanded material; Enthalpy; Crystallization; Microwave; Expanded graphite; Thermal energy storage; Phase transitions; Composite material; Intercalation compound; Phase transformation; Form-stable phase change materials; Irradiation; Thermal conductivity; Tetradecanol; PCM material; Solid phase; Comparative study
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2014.04.015

Natural flake graphite was chemically intercalated to prepare expandable graphite. The expandable graphite was then expanded by means of microwave irradiation to obtain expanded graphite (EG). Tetradecanol (TD)/EG composite form-stable phase change materials (PCMs) were prepared by mixing TD with EG through an autoclave method. The highest loading of TD in the composite form-stable PCMs with good form-stability was 93 wt%. The composite form-stable PCMs exhibited excellent thermal energy storage capacity. The melting enthalpy ([Delta]H sub(m)) and crystallization enthalpy ([Delta]H sub(c)) of the composite form-stable PCM containing 93 wt% TD were 202.6 and 201.2 J/g, respectively. However, the solid-solid phase transition of TD in the composite form-stable PCMs was hindered as TD was strongly absorbed by EG. As a result, the [Delta]H sub(m) and [Delta]H sub(c) of the composite form-stable PCMs were slightly lower than the theoretical value. The thermal conductivity of the composite form-stable PCMs was greatly enhanced by EG and was increased with the increasing of EG loading. The thermal conductivity of the composite form-stable PCM containing 7 wt% EG attained 2.76 W/m K. Besides, effects of the prepared EG on properties of the composite form-stable PCMs were compared with those of EG derived from commercially obtained expandable graphite.