Thermophysical properties of low-density Alder wood (Alnus cordata Loisel) under room ambience

The main objective of the study was to examine the thermophysical properties of Alder wood specimens as they relate to their volumetric density. Wood samples were subjected to controlled exposure conditions to assess their behavior after storage under room conditions of around 65% air humidity and a temperature of 20°C. This paper focuses on the results obtained by comparing the values of thermal diffusivity (κ), thermal conductivity (λ), and specific heat capacity (ρcp) measured at normal atmosphere and room pressure. The experiment was performed using the pulse transition method and all three basic thermophysical parameters were estimated from the measured temperature response to the heat pulse using a theoretical model derived for the cuboid geometry of the samples (cuboid model). The uncertainty of the estimated parameters using the Cuboid model is in the range of 1-3% depending onset of the experimental conditions and sample geometry. The model also includes the temperature of the heat exchangers and the influence of heat losses from the free surface of the sample to the surroundings in the lateral direction, which is represented by the heat transfer coefficient α. The thermophysical parameters obtained by the cuboid model using the Levenberg-Marquardt regression analysis applied to the thermal responses prove the prediction of a linear dependence with the bulk density of alder wood.