Effects of Pillar and Sealing Design on thermal and Mechanical Performance of Vacuum Insulated Glazing

Vacuum insulated glazing with a low-emittance coating has a great market potential as an effective transparent insulator. The thermal insulating performance of VIG is determined by its design, including material selection and configuration of different components. Thermal conductance of the vacuum gap, as a transport bottleneck, is one of the primary factors controlling the thermal transport across VIG. In particular, since support pillars and sealings provide the main thermal transport channels across the vacuum gap, increasing the pillar and sealing thermal resistance is a key strategy for effective thermal insulation, while maintaining the vacuum space and mechanical strength of VIG. In this research, the effects of various design parameters of pillar and sealing on the VIG thermal and mechanical performance were comprehensively investigated and discussed through the finite element method (FEM), along with experimental validation and analytical calculation. The results from the different approaches agree within 4%, providing confidence in the reliability of the employed approaches. The pillar design parameters, especially the height, shape, spacing, and arrangement of the pillars, showed significant effects on the thermal performance of VIG, the smaller contact area for horizontal pillars can effectively decrease the heat loss by more than 30%. An equation of pillar thermal performance was developed and presented. Sealing with flexible materials and sintered glass frits were tested in this work, both performed great performance in airtightness, but glass frits showed the limitation in the tensile test. Details of U-value effect and heat flux distribution of seal were analyzed and presented using FEM. Through this research, the guidance and suggestions for enhancing VIG performance through an optimized design of pillar and sealing are discussed.