Bio‐based phase change material for enhanced building energy efficiency: A study of beech and thermally modified beech wood for wall structures

Abstract

This study investigated the impregnation of beech and thermally modified beech (TMB) with a ternary mixture of capric acid, palmitic acid, and stearic acid as a bio‐based phase change material (BPCM). Finite element method (FEM) was used to complement the experimental analysis by providing new insights into computational methods for simulating the behavior of BPCMs in untreated and TMB. The analyzed specimens namely beech and TMB were impregnated with BPCM; the TMB achieved 54% weight percentage gain (WPG) while untreated beech got 37%. Accordingly, a greater increase in the latent heat was obtained for TMB up to 90 J/g, while for untreated beech with BPCM up to 75 J/g. Impregnated specimens absorbed less moisture at relative humidity of air above 50%, likely caused by the high uptake and hydrophobic nature of the BPCM. The study highlights the research gap in performing mathematical simulations on wood samples with BPCM using material thermal properties derived from differential scanning calorimetry or T‐History analysis. It shows that the direct use of these values for simulations leads to unacceptable outputs that result in high errors. The root mean square error for untreated and TMB samples impregnated with BPCM was in the range from 1.06 to 3.1 while that for untreated samples was in the range from 0.57 to 0.87, indicating that the main challenge in simulating and characterizing the samples is due to the interaction of the phase change material with the wood structure.

Thermal Performances and Stability of Capric Acid–Stearic Acid–Paraffin Wax Adsorbed into Expanded Graphite in Vacuum Conditions

“…Applying PCMs to the construction field and preparing new building energy storage materials combined with building materials can store a large amount of energy directly obtained from solar radiation in the building envelope, which is convenient to control the ambient temperature and meet the requirements of human comfort . At the same time, it can also achieve the effect of reducing energy consumption. − Therefore, PCMs have great application potential in energy reserves and conservation. Organic PCMs are being widely researched and applied currently.…”

Expanded Graphite (EG) Stabilization of Stearic and Palmitic Acid Mixture for Thermal Management of Photovoltaic Cells

“…Recently, fatty acid mixtures have been extensively studied in a wide variety of compositions [34][35][36], even if often their use in combination with EG excessively reduces the enthalpy of the composite material [37].…”