Within the scope of this article is the development of a mathematical model of an insulating panel made from grain husks and the optimization of the panel regarding the thermal characteristics by using this self-developed thermodynamically model. The model comprises one husk as the smallest unit of the insulating panel. In order to solve the model analytically, the following relevant parameters have been determined:

• husk geometry
• density of the pure husk material
• thermal conductivity of the pure husk material
• emission coefficient of the husk's surface
• convection coefficient inside the husks
• density of the binder
• thickness of the binder
• thermal conductivity of the binder

The solved model is validated with produced insulating panels out of grain husks. The optimization of the effective thermal conductivity λ_eff is done regarding the following parameters:

• the filling gas
• the edge length of the husks

According to the results of the simulation, by using Xenon as filling gas instead of air, the effective thermal conductivity λ_eff can be reduced by 21.6%. The optimal value of the husk’s edge length a depends on the filling gas und therefore varies between 4 and 6 mm. The optimization of the edge length leads to a reduction of the effective thermal conductivity λ_eff of 7.5 %, according to the model. When implementing individual calculated optimizations in real insulation boards, the thermal conductivity could be improved by up to 32 %. The project is funded by BMWi, the German ministry of economy and energy, and supervised by AiF, the working group of industrial research associations.