EVALUATION OF THERMAL PROPERTIES OF WOOD BASED COMPOSITE PANEL WALLS

Invention of light weight cellular wood material (CWM) with a trade mark of Dendrolight is one of the most important innovations in wood industry of the last decade. Currently CWM has been used as core material for sandwich-panels. These three layer panels are used in furniture industry and have wide non-structural applications. The aim of the research was to define the thermal properties of CWM and evaluate various wall envelopes where solid wood cellular material is used. There were 4 specimens of cellular wood material manufactured with nominal dimensions thickness 120 mm, length and with 600 mm to determine thermal conductivity and thermal transmittance according to standard EN 12667: 2002. The specimens were manufactured of four layer 112 mm thick Scots pine (Pinus sylvestris L.) CWM double faced with 4 mm thick high-density fiberboard (HDF). Adhesive used in the bonding process was polivinilacetate Cascol 3353. Each direction (parallel, perpendicular) was represented by two specimens. Common procedure to evaluate the energy efficiency of building envelope is to calculate thermal transmittance in static conditions. The influence of the cellular material orientation to its thermal properties was investigated. Coefficient of thermal conductivity was determined for both material directions of CWM (l(0) = 0.0977 W.m(-1).K-1 l(90) = 0.148 W.m(-1).K-1), combining the test method of EN 12667: 2002 and calculation method of standard EN 6946: 2008. To calculate thermal transmittance of various wall envelopes calculation software in JavaScript environment was created. Various compositions of external walls were assessed, thermal transmittance of these structures were calculated according to standard EN 6946: 2008.