Flexible phase change materials with enhanced tensile strength, thermal conductivity and photo-thermal performance

• Published in: Solar energy materials and solar cells 2021-01, Vol.219, p.110728, Article 110728
• Main Authors: Cai, Zhuodi, Liu, Jian, Zhou, Yanxue, Dai, Liling, Wang, Huixin, Liao, Chengcheng, Zou, Xuelin, Chen, Yanfeng, Xu, Yongjun
• Format: Article
• Language: English
• Subjects: Absorptivity; Elastomers; Elongation; Energy; Enthalpy; Exergy; Extrusion; Graphite; Heat conductivity; Heat transfer; Mechanical property; Paraffin; Paraffins; Phase change materials; Photo-thermal performance; Solar energy; Solar heating; Solar thermal systems; Tensile strength; Thermal conductivity; Thermal energy; Thermodynamic efficiency; Thermodynamics; Thermoplastic elastomer
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2020.110728

Phase change materials are most potential candidates for storing solar thermal energy with large enthalpy and high exergy. However, the intrinsic drawback such as poor optical absorptive capacity, low thermal conductivity and poor tensile strength restrict the thermal efficiency of phase change materials. To overcome drawback, expanded graphite is used to encapsulate the paraffin then thermoplastic elastomer is used to mix with the powders with twin-screw extrusion technology. The highly flexible phase change composite shows a melting enthalpy of 124.6 J g−1 and a thermal conductivity of 2.2 W m−1 K−1 with 70% of expanded graphite/paraffin. The tensile strength of 2.1 MPa and a breaking elongation of 220%. This flexible phase change composite demonstrates good photo-thermal energy charging/discharging property and shows much larger exergy than traditional fluids in the solar thermal energy systems. •①A flexible phase change composite with enthalpy of 124.6 J g−1 and a thermal conductivity of 2.2 W m−1 K−1.•②The phase change composite has tensile strength of 2.1 MPa and a breaking elongation of 220%.•③This phase change composite shows good photo-thermal energy charging/discharging property and large exergy.