Thermal energy storage and leakage prevention of phase change materials via one-step impregnation and in-situ polymerization process in hardwood

Abstract

Wood is a versatile material widely used in building construction, but its low thermal mass limits its ability to regulate indoor temperatures and mitigate thermal load peaks. Phase change materials are effective at storing thermal energy, but when impregnated into wood, they leak out, compromising performance and restricting their use in buildings. This study introduces a novel one-step impregnation process combined with in-situ polymerization using furfuryl alcohol and a capric-stearic acid phase change material mixture to create a sustainable material for thermal energy storage. Various formulations were tested on European beech (Fagus sylvatica L.) to evaluate effectiveness of the approach. The results confirm that this method successfully prevents phase change material leakage. Moreover, differential scanning calorimetry and nuclear magnetic resonance verified that phase change materials retain their thermal energy storage functionality, with no chemical cross-linking between the phase change materials and furfuryl alcohol. The treated wood showed up to 185 % higher thermal energy storage capacity, enhanced dimensional stability (anti-swelling efficiency up to 87 %), and 28 % higher compressive strength than untreated wood. It is a step towards sustainable, multifunctional, leakage-free, enhanced mechanical properties, improved dimensional stability wood for thermal energy storage for building applications, with potential for further optimisation and characterisation.

This work was partially funded by the Ministerio de Ciencia e Innovación - Agencia Estatal de Investigación (AEI) (PID2021- 123511OB-C31 - MCIN/AEI/10.13039/501100011033/FEDER, UE and RED2022-134219-T). This paper is part of the RYC2023-044196-I, funded by MCIU/AEI/10.13039/501100011033 and FSE+. The authors at the University of Lleida thank the Generalitat de Catalunya for the quality accreditation granted to the GREiA research group (2021 SGR 01615). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA inside the program ICREA Academia. The authors would like to thank Sara Risco and Franklin R. Martínez from University of Lleida for their help in the experiments carried out in this study. This research was supported by the Austrian Research Promotion Agency (FFG) under the project “Activation.Wood as part of the Waldfonds Initiative".Project number: 891640