Analysis of Wooden-framed Walls: Temperature and Humidity Evaluation

1. Department ofBuildingEngineering and Urban Planning, Facultyof Civil Engineerig, UniversityofZilina Pavol DURICA, Veronika KABATOVA, Peter JURAS, Jan RYBARIK HAM AnalysisofSelectedWooden-framedWalls

2. Introduction • The Department of building engineering and urban planning (UniversityofZilina)is dealing with the wooden structures for long time. Its laboratories and equipment are being constantly upgraded to better conduct research in the area of coupled heat-moisture transport in the building envelopes. Realized long-term measurements are compared and evaluated with help of simulation made with WUFI software. • In this paper are evaluated two selected walls with different orientation and similar composition. Evaluation is focused on the temperature and relative humidity courses during the winter and spring time period. Measured courses are compared with HAM simulation. Also the non-steady U-value courses are shown. 2205

3. Pavilionresearch • An expanded pavilion laboratory was launched at UNIZA in 2016 • Realoutdoor climate, changeable indoor climate • Twoexperimentalwalls • Southorientation • Eastorientation • Everywall has fivedifferentwallstructure • There is an air conditionerin the room • The walls differs with thermal insulation, outdoor surface, use of vapour barrier EAST SOUTH 2205

4. Pavilionresearch EAST orientation SOUTH orientation 2205

5. Selecteddiffuselyopenstructures 2205

6. Boundaryconditionused in simulation • Program forsimulation – WUFI Pro 5.1 • Exterior • Actualclimaticconditions in the city ofZilina • Selectedweek in 2018 – March 2 to 7 • Thelowesttemperaturewas -12,7°C on March 4, 2018 at 08:00 • Averagerelativehumiditywasabout 60% • Interior • Constanttemperature 20°C • Constantrelativehumidity 50% 2205

7. Comparisonofexperimentalmeasurements and simulations S2 S1 U = 0,09 W/(m2K) U = 0,10 W/(m2K) • Graphicallycomparedexperimentalmeasurementresultswithsimulatedresultsoftheexperimentalwall fragment sectionduringone chosen week 2205

8. Heat transfer coefficientwall „S1“ and „S2“ • Figure shows the progress of the heat transfer coefficient of the two wall fragments. For wall composition „S1“ the average coefficient of heat transfer is 0,149 W/(m2K). Second wall structure „S2“ has an average heat transfer coefficient of 0,15 W/(m2K). 2205

9. Selectedexperimentalmeasurementsoftemperature and relativehumidity 12.10.2018 – 18.10.2018 Eastorientation Southorientation 2205

10. Conclusion • This study pointed to a small temperature difference in two similar experimental wall fragments. The temperatures through the wall structure are similar. In some positions, higher temperature differences are observed. This is due to the different thermal insulation and heat-accumulation properties of the materials that have been used in the sandwich panels of wooden buildings. It also contains the passages of the heat transfer coefficients in the compared constructions. • Comparison of the measured parameters courses in the pavilion research and its simulation showed a significant match, which can be used in further research in variation of different boundary conditions in parametric studies. • Approximate agreement of heat transfer coefficient between theoretical value and non-stationary value from pavilion measurements was found. 2205

11. Conclusion • The favorable temperature and humidity regimes for both diffuse open tracks and their suitability for almost zero energy building needs were confirmed. • The heat transfer coefficients in the compared wall compositions showed markedly non-steady courses. This could be further used to calculate more precisely heat loss through the building envelopes based on the timber framed walls. • Compare the same structurewith different orientations:     - in the winter, lower surface temperatures at the eastern orientation versussoutherorientation  - summer - the south facing wall has layers in the outer zonehigher temperatures than outdoor temperatures • In the selected time periods, the selected compositions confirmed suitability for the realization of timber framed structures in passive buildings in terms of heat and moisture transport. 2205

12. Conclusion • A year-round analysis of the measurements provides information on the behavior of selected sandwich wood walls exposed to real climate conditions. • These laboratory measurements together with the simulations will be later verified by testing on samples taken in the climate chamber. Due to the different types of materials used and their combinations, it is possible to observe and compare their behaviour under the same boundary conditions from the exterior as well as from the interior. • The results of the pavilion research confirmed the favorable thermal-humidity regime of the selectedstructuresin the area of ​​thermal bridges and the installation of supporting elements in the walls. • The results of long-term experimental measurements will become part of a significant database of thermal-moisture characteristics of embedded materials. 2205

13. Veronika Kabatova veronika.kabatova@fstav.uniza.sk 2205