Experimental determination of thermal conductivity of fatty acid binary mixtures and their shape-stabilized composites

Abstract

Thermal conductivity is an essential property to understand the rate of charging/discharging of thermal energy storage systems, but there is still a lack of experimental studies in this field. The temperature dependence of thermal conductivity of eutectic mixtures capric/myristic acid (CA/MA), lauric/myristic acid (LA/MA), and palmitic/stearic acid (PA/SA), as well as their respective shape-stabilized forms (SSPCMs), were measured by the hot wire technique. Thermal conductivity presented a linear correlation with temperature for all the materials. Besides, the thermal conductivity of the samples was compared with a commercial SS-PCM finding out that the SS-PCMs produced by the authors exhibit higher thermal conductivity than the commercial sample, with an increase between 10.57% and 33.33%. In addition, the minerals that comprise the clay were acquired and their effect on the thermal conductivity on the support studied. Between the crystalline phases, kaolin governed the thermal conductivity of the support. Afterward, kaolin additions were made, resulting in an increase of thermal conductivity between 6.49% and 17.68% of the SS-PCM. Thus, the novelty of this study relies, first, on the experimental data obtained of thermal conductivity, and second, on the study of the effect of some minerals in the overall thermal conductivity of the samples.

The authors are pleased to acknowledge the financial assistance of the “Ministerio de Ciencia, Tecnología e Innovación- MINCIENCIAS” through the PhD grant 758-2016-Contract 036–2016, Universidad de Antioquia and Sumicol S.A.S. This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31 - MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación (AEI) (RED2018-102431-T). The authors at the University of Lleida would like to thank the Catalan Government for the quality accreditation given to her research group GREiA (2017 SGR 1537). GREiA is a certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme.