Numerical analysis and experimental investigation on thermal bridge effect of vacuum insulation panel

Vacuum insulation panel, composed of a core material and a barrier, is a very efficient thermal insulation material. Compared with conventional insulation materials, the vacuum insulation panel is proposed to achieve a better insulated performance. However, its thermal conductivity will be seriously increased and insulated performance will be significantly decreased since the additional heat is transferred through the barrier; that is called thermal bridge effect. This paper emphasized on effective thermal conductivity to evaluate the performance of vacuum insulation panel. Two criteria, i.e., the linear and point thermal transmittance are introduced to evaluate the comprehensive performance of vacuum insulation panel. A heat transfer model was used to analyze the thermal bridge. Then, a fast and effective method for measuring thermal bridge is presented, which is supported by numerical simulation analysis. The results indicated that thermal bridge not only could increase with the increasing of the mental foil (main aluminum) thickness, but also could exhibit higher heat losses with the reducing of thickness of the vacuum insulation panel. Overall, the effective thermal conductivity of vacuum insulation panel could increase by 110.8% when the barrier contains 10 μm mental foil and the size of vacuum insulation panel is 300 × 300 × 10 mm3. This research provides a reference for measuring the thermal bridge and could also disclose the quantitative behavior of physical parameters in thermal bridge.