Insulation & Facades

Examination of beech and grand fir in regard to developing innovative wood-based materials – Environmentally friendly insulation made of beech wood

This project examined the use of beech wood fibres for the production of high quality insulation products. Such products make a positive contribution to climate protection by supporting CO2 neutrality and the conservation of fossil resources. The wood in question can be dried using microwave ovens, which is significantly more energy efficient than conventional drying methods.

Summary


Materials used for insulation are chosen because of their low thermal conductivity. Such materials include wood fibres, with beech and forest wood fibres considered among the most promising for the production of novel composite materials. The current project investigated the suitability of beech and grand fir fibre for the manufacture of insulating boards using a wet process followed by drying in a microwave oven. Previously, manufactured wood fibre insulation was convectively dried in gas-fired dryers, which is both highly energy and time consuming. In such a dryer, 20mm thick fibre insulation boards at a temperature of 160 to 220 °C require over two hours for drying. In more efficient microwave heating, electromagnetic energy is introduced directly into the material being heated, where the molecule groups absorb it and convert it into heat energy. The wood fibre insulation boards were examined in regard to their chemical and thermodynamic properties as well as in regard to their temperature distribution and drying dynamics.

Results:

  • The microwave drying of fibre insulation boards produced using a wet process (20mm) is twelve times faster than conventional drying, though the energy consumption remains approximately equal.
  • The use of microwave technology also allows for the production of thicker insulation boards (> 20mm), thereby foregoing the bonding of thinner insulation boards.
  • The total energy consumption of the 6.6 kW plant for drying 20mm thick insulating mats was 4700 kJ per kilogram of evaporated water.
  • With the addition of 10% potato pulp, the transverse tensile strength of wood fibre insulation boards made of beech wood reached a level equal to that of industrially manufactured wood fibre insulation boards made of soft wood.
  • The thermal conductivity of wood fibre insulation boards made of beech wood tended to be higher than in industrially produced wood fibre insulation boards made of soft wood.
  • The bonding strength of the timber and the interlocking of the fibres result in stable insulating panels, thereby avoiding the use of bonding agents.

More Project Information

Project title: Verbundprojekt: Untersuchungen der Holzarten Buche und Küstentanne aus nachhaltig bewirtschafteten Mischbeständen zur Herstellung innovativer zukunftsfähiger Holzprodukte und Holzwerkstoffe, Teilprojekt 5 - Herstellung von umweltfreundlichen, organisch gebundenen Dämmstoffen

Project number: 0330551E

Project period: 2005 - 2008

Project region: Germany (Lower Saxony)

Project contact:

Herr Prof. Dr. Kharazipour

Herr Prof. Dr. Viöl

View Publication

Source: German National Library of Science and Technology Hannover (TIB)