Thermal Conductivity Measurement of Vacuum Tight Dual-Edge Seal for the Thermal Performance Analysis of Triple Vacuum Glazing

A vacuum tight glass edge seal’s thermal conductivity is one of the principal factor in determining the heat distribution towards the centre of pane, ultimately influences the thermal transmittance (U-value) of a triple vacuum glazing. So far indium and solder glass have proven to be vacuum tight edge sealing materials but both have certain limitations. In this chapter, a new low-temperature vacuum tight glass edge seal composite’s thermal conductivity, Cerasolzer CS186 alloy and J-B Weld epoxy-steel resin, were measured and validated with the mild-steel and indium using transient plane source method with a sensor element of double spiral and resistance thermometer in a hot disk thermal constants analyser TPS2500s are reported. The thermal conductivity data of Cerasolzer CS186 alloy and J-B Weld epoxy steel resin were measured to be 46.49 and 7.47 W/m/K, with the deviations (using analytical method) of +/- 4% and +/-7% respectively. These values were utilised to predict the thermal transmittance value of triple vacuum glazing using 3D finite element model. The simulated results show the centre-of-glass and total U-value of 300 x 300 mm triple vacuum glazing to be 0.33 and 1.05 W/m2/K, respectively. The influence of such a wide edge seal on the temperature loss spreading from the edge to the central glazing area is analysed, in which the predictions show wider edge seal has affected the centre-of-glass U-value to 0.043 W/m2/K due to the temperature gradient loss spread to 54 and 84 mm on the cold and warm side respectively.