Encapsulated vacuum insulation panels: Theoretical thermal optimization

A vacuum insulation panel (VIP) is a new thermal insulation material consisting of an open-celled core material which is evacuated and then sealed with a thin barrier laminate. When it is integrated into an expanded polystyrene (EPS) insulation board and entirely encapsulated by a protective material, an additional thermal bridge occurs along the component's perimeter. A theoretical parameter study examines the effects of integrating a VIP into an insulation board with a fixed thickness of 100mm. Several parameters were varied: thermal conductivity and the thickness of the VIP core, the thickness of the envelope, the thickness of the EPS layers and the width of the EPS strips along the component's perimeter. Both two- and three-dimensional numerical studies reveal a certain VIP maximum thickness for optimal thermal performance. For the three-dimensional component, this thickness is near 30mm or 95mm for, respectively, a 40m- or a 6m-thick aluminium foil-based barrier laminate. For these components, the overall thermal resistance was found to be, respectively, 35% or 137% higher than a 100mm-thick EPS insulation board. However, no maximum thermal performance was found for an encapsulated VIP containing a three-layer metallized barrier laminate.