Development of an experimental bench for investigating heat and moisture transfer in porous materials

Abstract

Abstract Heat and moisture transfer in porous materials play a critical role in a wide range of engineering and environmental applications, particularly in the building sector, where such processes affect energy efficiency, material durability, and indoor comfort. Accurate experimental data are essential for understanding these phenomena and for validating numerical models that simulate heat, air, and moisture (HAM) transport. However, acquiring reliable measurements under controlled conditions remains a significant challenge due to the complexity of coupled transport processes. This paper presents the development of an experimental bench designed to investigate heat and moisture transfer in porous materials. The system enables precise control and measurement of key environmental parameters, including air temperature (15–50 °C), relative humidity (15–98%), and velocity (0.1–5 m/s). Operating in a closed-loop configuration, the setup ensures high stability, minimises the influence of external conditions, and reduces the power consumption of system components. The experimental bench was equipped with a cooler/moisture condenser, a variable-speed fan, a humidifier, and a heater, each regulated by custom-designed Proportional–Integral–Derivative (PID) controllers to maintain precise and stable operating conditions. Temperature within the samples was monitored using multiple first-class T-type thermocouples, while moisture content was measured gravimetrically through continuous mass monitoring. A feature of the setup is the inclusion of two parallel measurement ducts, which allow for simultaneous testing under identical conditions and enable faster verification of repeatability and reliability. Initial tests conducted with autoclaved aerated concrete samples are presented in the paper and confirm the system’s capability for stable and repeatable operation. The maximum standard deviation observed in temperature control was approximately 0.22 °C, while for relative humidity it reached up to 0.93%. These levels of precision support the acquisition of representative experimental data suitable for validating HAM transfer models in porous materials.