Comparative measurements of heat and moisture transport in wood based constructions

In this study the heat and the moisture transport parameters of three wood based constructions are compared. Two of the tested constructions are conventional wood frame constructions (with one and two insulation layers). The third construction is a solid wood construction connected with wooden dowels without any further binder. Three small test buildings without openings were constructed for this experiment. The measurements were carried out under natural weather conditions at the campus of the ETH Zurich. Indoor temperature and the temperature within the walls, indoor relative humidity and the climate data of outdoor environment were measured from February 2007 for a period of one year. The results show a higher thermal protection of indoor environment by the solid wood construction during summer. During winter, the thermal stability of the solid wood construction is advantageous compared to both conventional wood frame constructions due to a slower cooling of walls. In the conventional wood frame constructions, the relative humidity inside test buildings continuously increased during the whole experiment. In contrast, the relative humidity in the solid wood construction was constant at a level of 40 to 48 %. The measured temperatures were compared with numerical simulation results. For this purpose, the simulation software Delphin was used. The validation shows that Delphin is useful to simulate heat transport in test buildings. Test results indicate, together with thermal parameters like phase shift of thermal oscillation and thermal damping factor, that the most comfortable indoor environment can be achieved with the solid wood construction.