INFLUENCE OF MOISTURE CONTENT OF MHM SOLID WOOD WALL CONSTRUCTION MATERIALS ON THERMAL CONDUCTIVITY
Keywords:
moisture status of materials, thermal conductivity, MHM solid-wood panels, wood-fiber insulation, straw insulationAbstract
The moisture content of materials in building structures is a factor that affects the amount of heat losses through the building envelope. In the context of the current demands for increased thermal protection, the moisture content of materials becomes an important indicator of thermal and technical properties. The paper is devoted to the theoretical and experimental analyses of the moisture condition of the construction materials of panel exterior walls made from solid MHM (Massiv-Holz-Mauer) panels. The theoretical analyses of the moisture status of materials through the WUFI 2D simulation program were supplemented by experimental measurements of moisture in built-in structures. The measurements took place in a research building simulating the creation of residential climate conditions. The research quantified the influence of the operating moisture status of MHM and blown thermal insulations (wood fibres and disintegrated straw) on their thermal conductivity. The research results show that the moisture content of MHM panels influences their thermal conductivity in natural conditions. However, in the case of wood-fibre insulation, no significant influence of moisture status on the coefficient of thermal conductivity was demonstrated. The moisture content of disintegrated straw indicates that in natural conditions, it acquires 46% higher thermal conductivity values than the ones declared by the manufacturer.
References
Asdrubali, F., Ferracuti, B., Lombardi,L., Guattari, C., Evangelisti, L., Grazieschi, G., 2016. A review of structural, thermo-physical, acoustical, and environmental properties of wooden materials for building applications. Building and Environment, 114. ELSEVIER Ltd. p. 317-319. https://doi.org/10.1016/j.buildenv.2016.12.033
Božiková, M., Kotoulek, P., Bilčík, M., Kubík, Ľ., Hlaváčová, Z., Hlaváč, P., 2021. Thermal properties of wood and wood composites made from wood waste. International Agrophysics, 35(3). p. 251-256. https://doi.org/10.31545/intagr/142472
Bunkholt, S., N., Ruther, P., Gullbrekken, L., Geving, S., 2021. Effect of forced convection on the hygrothermal performance of a wood frame wall with wood fibre insulation. Building and Environment, 195. 107748. ELSEVIER Ltd. https://doi.org/10.1016/j.buildenv.2021.107748
Carfrae, J., 2009. Long-term evaluation of the performance of a straw bale house built in a temperate maritime climate. Doctoral research workshop – Sustainability in the Built Environment November 16, 2009, University of Plymouth, UK.
Cascone, S., Evola, G., Gagliano, A., Sciuto, G., Baroetto Parisi, CH., 2019. Laboratory and in-situ measurements for thermal and acoustic performance of straw bales. Sustainability 11, 5592. https://doi.org/10.3390/su11205592
Cascone, S., Catania, F., Gagliano, A., Sciuto, G., 2018. Energy performance and environmental and economic assessment of the platform frame system with compressed straw. Energy Build. 166, 83–92. https://doi.org/10.1016/j.enbuild.2018.01.035
Flity, H., Jannot, Y., Terrei, L., Lardet, P., Schick, V., Acem, Z., Parent G., 2024. Thermal conductivity parallel and perpendicular to fibres direction and heat capacity measurements of eight wood species up to 160 °C. In. international Journal of Thermal Sciences 195. https://doi.org/10.1016/j.ijthermalsci.2023.108661
Gallegos-Ortega, R., Magaña-Guzmán, T., Reyes-López, J.A., Romero-Hernández, M. S., 2017. Thermal behaviour of a straw bale building from data obtained in situ. A case in Northwestern México. Build. Environ. p.124, 336–341. https://doi.org/10.1016/j.buildenv.2017.08.015
Geving, S., Holme, J., 2012. Vapour retarders in wood frame walls and their effect on the drying capability. In. Frontiers of Architectural Research, 2 (1). s. 42-49. https://doi.org/10.1016/j.foar.2012.12.003
Geving, S., Lunde, E., Holme, J., 2015. Laboratory investigations of moisture conditions in wood frame walls with wood-fibre insulations. 6th International Building Physics Conference, IBPC 2015. Energy Procedia, 78. ELEVIER Ltd. p. 1455-1460. https://doi.org/10.1016/j.egypro.2015.11.170
Goodhew, S., Griffiths, R., 2005. Sustainable earth walls to meet the building regulations. Energy Build. 37, p. 451–459. https://doi.org/10.1016/j.enbuild.2004.08.005
Gullbrekken, L., Grynning, S., Gaarder, E., J., 2019. Thermal performance of insulated constructions – experimental studies. Buildings, 9 (2). https://doi.org/10.3390/buildings9020049
Hrčka, R., 2010. Variation of thermal properties of beech wood in the radial direction with moisture content and density. Proceedings of the 6th IUFRO Symposium “Wood structure and Properties ´10” held on September 6-9, 2010 in Podbanské, High Tatras, Slovakia and organized jointly by the Faculty of Wood sciences and Technology of the Technical University in Zvolen and the IUFRO Research Groups 5.01. “Wood Quality”. Arbora Publishers, Zvolen, Slovakia. ISBN: 978-80-968868-5-2
Kotoulek, P., Malínek, M., Božiková, M., Hlaváč, P., Bilčík, M., Hlaváčová, Z., Scilag, J., 2018. Basic thermal properties and geometric characteristics of wood and oriented strand board used in low-energy buildings. Journal of Processing and Energy in Agriculture, 22 (2). p. 73 – 75. ISSN:1821-4487.
Krišťák, Ľ., Igaz, R., Ružiak, I. 2019. Applying the EDPS Method to the Research into Thermophysical Properties of Solid Wood of Coniferous Trees. Advances in Materials Science and Engineering, vol. 2019. https://doi.org/10.1155/2019/2303720
Platt, L. S., Maskell, D., Shea, A., Walker, P., 2022. Impact of fibre orientation on the hygrothermal properties of straw bale insulation. Construction and building materials 349. ELSEVIER Ltd. https://doi.org/10.1016/j.conbuildmat.2022.128752
Regináč, L., Babiak, M., 1977. Základné tepelnofyzikálne charakteristiky smrekového dreva pri normálnych podmienkach [Basic thermal physical characteristics of spruce wood under normal conditions]. Drevársky výskum, Ročník XXII. Zväzok 3. pp. 165–183.
Robinson, J., Klalib Aoun, H., Davison, M., 2017. Determining moisture levels in straw bale construction. Procedia Engineering, 171. p. 1526-1534. ELSEVIER Ltd. https://doi.org/10.1016/j.proeng.2017.01.390
Shea, A., Wall, K., Walker, P., 2013. Evaluation of the thermal performance of an innovative prefabricated natural plant fibre building system. Build. Serv. Eng. Res. Technol. 34, p. 369–380. https://doi.org/10.1177/0143624412450023
STN 73 0540-2 + Z1 + Z2: 2019 Tepelnotechnické vlastnosti stavebných konštrukcií a budov. Tepelná ochrana budov. Časť 2: Funkčné požiadavky [Thermal technical properties of structures and buildings. Thermal protection of buildings. Part 2: Requirements].
STN EN 322 Dosky z dreva. Zisťovanie vlhkosti [Wood-based panels. Determination of moisture content].
STN EN ISO 10456 Stavebné materiály a výrobky. Tepelno-vlhkostné vlastnosti. Tabuľkové návrhové (výpočtové) hodnoty a postupy na stanovenie deklarovaných a návrhových hodnôt tepelnotechnických veličín [Building materials and products. Hygrothermal properties. Tabulated design values and procedures for determining declared and design thermal values].
Štompf, P., Jochim, S., Uhrín R., 2022. Prototypový výskumný object Katedry drevených stavieb Technickej university vo Zvolene. Nové trendy akustického spektra: vedecký recenzovaný zborník [Prototype research object of the Department of Wooden Constructions of the Technical University in Zvolen. New Trends of Acoustic Spectrum: a peer-reviewed proceedings] p. 103-123. ISBN: 978-80-228-3325-7.
Štompf, P., 2023. Identifikácia a analýza vybraných parametrov drevených stavebných konštrukcií z hľadiska spotreby energie: Dizertačná práca. [Identification and analysis of selected parameters of timber structures in terms of energy consumption: Dissertation]. Zvolen: Technical University in Zvolen. Faculty of Wood Sciences and Technology, Department of Wooden Constructions. p. 48-93
Teslík, J., 2016. Výzkum vlastností drcené slámy využitelné ve stavebnictví. Disertační práce. Ostrava: Vysoká škola báňská – Technická univerzita Ostrava. Stavební fakulta. [Research on the properties of crushed straw usable in the construction industry. Dissertation.] p. 92.
Volf, M., Diviš, J., Havlík, F., 2015. Thermal, moisture and biological behaviour of natural insulating materials. Energy Procedia, 78. p. 1599-1604. Elsevier Ltd. https://doi.org/10.1016/j.egypro.2015.11.219
Wang,Y., Zhao, Z., Liu, Y., Wang, D., Ma, CH., Liu, J., 2019. Comprehensive correction of thermal conductivity of moist porous building materials with static moisture distribution and moisture transfer. Energy. Elsevier Ltd. p. 103-118. https://doi.org/10.1016/j.energy.2019.03.178
Zhang, J., Wang, J., Guo, S., Wei, B., He, X., Sun, J., Shu, S., 2017. Study on heat transfer characteristics of straw panel wall in solar greenhouse. Energy Build. 139, p. 91–100. https://doi.org/10.1016/j.enbuild.2016.12.061
