Modified clay as thermal backfill material for buried electrical cables

• Published in: Thermal science and engineering progress 2020-10, Vol.19, p.100589, Article 100589
• Main Authors: Suleiman, Bashir M., Daoudi, Kais, Attaelmanan, Atta G., Alzaylaie, Marwan, Gustavsson, Mattias
• Format: Article
• Language: English
• Subjects: Clay backfill; IEC 287; Thermal conductivity; Transient Plane Source; U-value; Underground buried transmission lines
• ISSN: 2451-9049; 2451-9049
• DOI: 10.1016/j.tsep.2020.100589

•Thermal properties of Al-modified clay-bentonite have been investigated.•Thermal conductivity increased from 0.25 to 0.68 W/m-K, as the Al-content increased by 25%.•The average U-values have been found in the range from 0.40 to 1.1 W/m2 K.•The Al-modified clay bentonite material was found to be a promising candidate for backfill materials applications. The power efficiency of underground cables is largely affected by the thermal conductivity of the surrounding (backfill) materials hosting the cables/tubes. We are investigating the possibility to enhance thermal conduction in Al-modified clay-bentonite to be used as backfill materials. The Transient Plane Source (TPS) technique is used to measure thermal conductivity. The measurements were performed on five dry samples at room temperature. They were done on an isotropic basis using different amounts of Al concentration (0%, 6%, 8%, 13%, and 25%) of the sample weight. The results showed an overall substantial relative increase in the thermal conductivity values from 0.25 W/m-K to 0.68 W/m-K, as the Al-content increased by 25%. The estimated average U-values of these samples were in the range from 0.40 to 1.1 W/m2 K, which are directly proportional to the relative increase in the measured thermal conductivity.