Finite element analysis of heat transfer performance of vacuum glazing with low-emittance coatings by using ANSYS

Abstract

As a new transparent insulation material, vacuum glazing with Low-E (low emittance) coating has drawn more and more attentions thanks to its excellent performances: outstanding thermal and sound insulations, anti-frosting, resisting wind press capacity, and good durability. However, a comprehensive analysis and evaluation on the heat transfer performance of Low-E vacuum glazing are still missing in the current literatures. In this work, the influences of various aspects on the heat transfer performance of Low-E vacuum glazing were analyzed based on the Finite Element Analysis (FEA) method, including thickness of substrate glass, width of the sealing edge, materials and spacing of support pillar array, and insulation frame structure. The simulated results show the following, 1) with the increase of the thickness of the substrate glass, the heat transfer coefficient of the Low-E vacuum glazing rises slowly in a linear trend. The larger the size of the whole piece of the glazing, the more slowly it rises; 2) the Low-E vacuum glazing heat transfer coefficient declines linearly with the decrease of the width of the sealing edge; 3) as the support pillar array spacing increases and the thermal conductivity of the support pillar array decreases, the Low-E vacuum glazing heat transfer coefficient decreases; 4) the use of thermal insulation frame structure can improve the insulation efficiency of the vacuum glazing. Experiments were carried out on a Low-E vacuum glazing, and the heat transfer coefficient of this vacuum glazing was determined by the Building Heat Resistance-III (BHR-III), an equipment for insulation performance testing. The simulated result matches well with the experimental result, with a relative deviation of 2.8%, which confirms the reliability of the simulation result. This work is expected to provide guidance for optimization design of Low-E vacuum glazing and its insulation performance evaluation.