Iranian Journal of Wood and Paper Industries

Iranian Journal of Wood and Paper Industries

Investigation of the Thermal Energy Storage Potential of Wood Using Capric Acid as a Phase Change Material

Document Type : Research Paper

Authors
Siroos Habibzade 1
Behbood Mohebby 1
Seyed Mojtaba Sadrameli 2
Cemil Alkan 3
1 Department of Wood and Paper Science and Technology, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, Iran
2 Department of Process Engineering, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran, Iran. , Department of Engineering, German University of Technology in Oman, Muscat, Oman.
3 Department of Physical Chemistry, Faculty of Arts and Sciences, Gaziosmanpaşa University, Tokat, Turkey
10.22034/ijwp.2026.2078748.1743
Abstract
Abstract
Problem definition and objectives: In recent years, optimizing energy consumption in buildings has become one of the main research priorities in the fields of building engineering and energy. The integration of phase change materials into building materials and components such as walls and ceilings has gained significant attention as an innovative approach to enhance thermal energy efficiency. By increasing thermal mass and thermal inertia, these materials considerably enhance the heat-storage performance of building elements, particularly in lightweight structures that inherently have limited energy-storage capacity. Capric acid, as one of the most widely used phase change materials, has a melting point close to the human thermal comfort range, making it a suitable candidate for thermal energy storage in indoor building environments. Wood and wood-based products are extensively used in interior building components due to their favorable mechanical properties and environmental benefits. However, their natural thermal energy storage capacity is relatively low. The main objective of this research is to investigate the application of capric acid as a phase change material impregnated into a poplar wood matrix, aimed at enhancing the thermal energy storage performance of wood-phase change material composite systems.
Methodology: To investigate the thermal energy storage performance, poplar wood samples were first oven-dried at 103 °C for 24 hours and then weighed. Subsequently, the dried samples were placed in a suitable container and transferred to a vacuum drying oven to evacuate air from the cellular pores of the wood. A solution of capric acid was then added to the samples, and the vacuum process was repeated to ensure penetration of the phase change material into the wood structure. Finally, the impregnated samples were dried under ambient conditions for 24 hours until constant mass was achieved. In this study, Differential Scanning Calorimetry (DSC) analysis was employed to evaluate the thermal capacity and phase-change behavior of the samples at different temperatures. Thermal cycling tests were conducted using a Cycling Test apparatus under controlled temperature conditions. Additionally, the surface temperature distribution of the samples was recorded and analyzed using an infrared thermal camera.
Results: The DSC analysis showed that the wood/capric acid composite samples had a melting and freezing temperature of 2/28°C and 9/23°C, respectively. The thermal energy storage capacity of the samples was reduced by approximately 55% compared to pure capric acid which can be explained by several factors, the confinement of the phase change material within the wood pores, the low thermal mass of the wood and capillary interactions between capric acid and the cell walls of the wood Furthermore, thermal cycling tests demonstrated that the wood samples containing capric acid exhibited a significant delay in temperature fluctuations compared to the samples without phase change material, allowing for improved energy efficiency and reduced temperature variations in indoor environments. Infrared thermal imaging also confirmed that the samples containing capric acid had higher surface temperatures and distributed heat more uniformly.
Conclusion: This research investigated the application of capric acid as a phase change material in poplar wood to enhance thermal energy storage performance in building applications. The results demonstrate that impregnating wood with capric acid significantly increases its thermal energy storage capacity and effectively reduces temperature fluctuations. Moreover, the wood-phase change material composites exhibited improved thermal behavior, including a more uniform heat distribution. This approach can contribute to reduced energy consumption for heating and cooling while enhancing indoor thermal comfort for occupants.
Keywords
Poplar wood
Phase Change Materials (PCM)
Capric Acid
Thermal Energy Storage
Thermal Cycling
Subjects
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Iranian Journal of Wood and Paper Industries
Volume 17, Issue 2
Summer 2026
Pages 383-397