Development of the experimental stand for investigation of heating and drying phenomena in the porous building materials with one surface of the sample exposed to the flowing air

Abstract

The paper presents development of the experimental stand for investigation of heating and drying phenomena in the porous building materials with one surface of the sample exposed to the flowing air. Moreover, results of preliminary measurements which verify the range of operating conditions achieved by the stand are shown. These conditions were assumed in the following range: 15℃-60℃, 10-90% and 0.1-10 m/s for temperature, relative humidity and velocity of the flowing air, respectively. In order to control the parameters of air used for heating and drying of porous materials, a closed-loop concept of the stand was proposed and equipped with several elements, i.e., the cooler (vapour condenser), fan with variable rotational speed, humidifier and heater. Furthermore, two parallel measurement ducts which allow to obtain two air streams with identical parameters were proposed. This enables two measurements at one time as well as faster verification of the repeatability of the performed measurements. The temperature measurements at the top surface and inside the sample are carried out applying the IR thermography and several K-type thermocouples, respectively, while overall moisture amount and the moisture content distribution in the specimen are found using tensometric force and electrical resistance meters, respectively.

Analysis of Non-Equilibrium and Equilibrium Models of Heat and Moisture Transfer in a Wet Porous Building Material

“…Their further development will also be related to their validation. It will be performed with experimental stands which are under development and testing and which are described in recent publications [19,20].…”

“…The idea of a separated solver was utilized. This means that in each iteration the balance equation for moisture, given by Equation (11), was solved first and then the supplementary material properties (Equations (17)- (19)), mass fluxes (Equations (3) and (4)), as well as volumetric moisture contents in gaseous and liquid phases (Equation (15)), were evaluated. In the last step the balance equation of energy, given with Equation (12), was solved.…”

Efficiency Comparison between Two Masonry Wall Drying Devices Using In Situ Data Measurements

“…The most problematic as well as time-and energy-consuming step is the first step of the renovation of wet walls, in which masonry walls are dried by applying different techniques (e.g., convective [4][5][6], vacuum [7] or microwave drying [2,8]). Therefore, in order to improve the overall efficiency of the masonry wall renovation process, the drying step should be optimized.…”