Enhancement of heat transfer for thermal energy storage application using stearic acid nanocomposite with multi-walled carbon nanotubes

• Published in: Energy (Oxford) Vol. 55; pp. 752 - 761
• Main Authors: Li, TingXian, Lee, Ju-Hyuk, Wang, RuZhu, Kang, Yong Tae
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.06.2013; Elsevier
• Subjects: Applied sciences; calorimeters; carbon nanotubes; Energy; Energy. Thermal use of fuels; Exact sciences and technology; freezing point; Heat transfer; melting point; Multi-walled carbon nanotube; Nanocomposite; nanocomposites; phase transition; scanning electron microscopy; Stearic acid; temperature; Theoretical studies. Data and constants. Metering; thermal conductivity; Thermal energy storage; Thermal energy storage; Nanocomposite; Stearic acid; Multi-walled carbon nanotube; Heat transfer; Carbon nanotubes; Wall
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2013.04.010

A latent heat storage nanocomposite made of stearic acid (SA) and multi-walled carbon nanotube (MWCNT) is prepared for thermal energy storage application. The thermal properties of the SA/MWCNT nanocomposite are characterized by SEM (scanning electron microscopy) and DSC (differential scanning calorimeter) analysis techniques, and the effects of different volume fractions of MWCNT on the heat transfer enhancement and thermal performance of stearic acid are investigated during the charging and discharging phases. The SEM analysis shows that the additive of MWCNT is uniformly distributed in the phase change material of stearic acid, and the DSC analysis reveals that the melting point of SA/MWCNT nanocomposite shifts to a lower temperature during the charging phase and the freezing point shifts to a higher temperature during the discharging phase when compared with the pure stearic acid. The experimental results show that the addition of MWCNT can improve the thermal conductivity of stearic acid effectively, but it also weakens the natural convection of stearic acid in liquid state. In comparison with the pure stearic acid, the charging rate can be decreased by about 50% while the discharging rate can be improved by about 91% respectively by using the SA/5.0% MWCNT nanocomposite. It appears that the MWCNT is a promising candidate for enhancing the heat transfer performance of latent heat thermal energy storage system. •A nanocomposite made of stearic acid and multi-walled carbon nanotube is prepared for thermal energy storage application.•Effects of multi-walled carbon nanotube on the thermal performance of the nanocomposite are investigated.•Multi-walled carbon nanotube enhances the thermal conductivity but weakens the natural convection of stearic acid.•Discharging/charging rates of stearic acid are increased/decreased by using multi-walled carbon nanotube.