Within the research project "Potentials of hygrothermally activated building components" (PhyTAB)- the potential of hygroscopically active surfaces (HAO) in particular- is being investigated with the aim of applying this knowledge to further developments of a thermally activated solid timber components (TAM). A literature review sets the foundation for laboratory measurements to quantify the so-called hygrothermal effect on surfaces. The heating of wood and clay surfaces due to the release of sorption enthalpy after water vapor adsorption can clearly demonstrated in laboratory experiments. In this research project, these investigations will be transferred to observations under real conditions in a test chamber subjected to the influence of the local weather conditions. For this purpose, two measuring cubes are designed, planned and put into practice. An appropriate measurement, supply and electrical concept forms the basis for the experiments. This implementation serves the function to detect the hygroscopic behaviour. The setup of these cubes enables a theoretical preselection of materials by simulations and provides recommendations for the control strategies for the hygrothermally-optimized use of the TAM surface. Drawing on the conclusion of the hygroscopically active surfaces, the results suggest that the hygrothermal processes can be reproduced with the selected test setup. Here, the different component structures exhibit different behaviours. The heating of the inside of a cross-laminated timber construction after an isothermal moisture jump can be successfully measured using the methods adapted from the laboratory tests. The comparison of an untreated and a varnished cross-laminated timber surface proves the discrepancy in the transient hygric as well as hygrothermal behaviour. With regard to the fluctuations of the interior temperature in the centre of the test cube, minor thermal buffering effects can be observed allocated to the sorption heat in certain measurement periods. A further long-term comparison shows that the modification of a cross-laminated timber construction with an interior clay building board and plaster mainly creates buffering effects based on the increase of the thermal mass. Overall, the hygrothermal effects (the thermal buffering effects of hygroscopic surfaces) are traceable to a much smaller extent in the outdoor test cubes than recorded in the previous laboratory experiments. The hygrothermal simulations also show that the hygric effect complements the thermal effects of the materials and that the surface temperature can thus be additionally increased under active conditioning by humidification. This could form the basis for further research projects to investigate the influence from thermally active surfaces on the interior of a building. The results of the project with regard to the thermally activated solid timber element outline that it is possible to install the element up to building class 5, under the condition that the building authorities approve the solid timber element. The connection to the adjoining building structure as well as to the building technology is feasible in lines with the current state of the art and does not require any additional investigations. A wall structure with façade, insulation and the thermally activated solid timber element can meet the current requirements for thermal insulation, fire protection, noise protection, etc. A consideration of the ecological life cycle according to DIN EN 15804:2020-03 was carried out for the modules A1 - A3, A5, C2 - C4 and D in this report.     «

Within the research project "Potentials of hygrothermally activated building components" (PhyTAB)- the potential of hygroscopically active surfaces (HAO) in particular- is being investigated with the aim of applying this knowledge to further developments of a thermally activated solid timber components (TAM). A literature review sets the foundation for laboratory measurements to quantify the so-called hygrothermal effect on surfaces. The heating of wood and clay surfaces due to the release of s...     »