THERMAL ANALYSIS AND OVERHEATING PROTECTION FOR CURTAIN WALLS

Boundary conditions and typical curtain wall systems

In this paper, Shenzhen (22° north latitude), Guangdong Province of China is selected as the representative of the subtropical climate. The summer outdoor temperature and solar irradiance in Shenzhen are shown in Table 1 [3], the outdoor wind speed is 2.2 m/s, and the outdoor convective heat transfer coefficient is 12.8 W/(m2·K), the indoor convection heat transfer coefficient is 2.5 W/(m2·K), the indoor temperature is 25ºC , and the indoor relative humidity is 50%.

The head transom is selected as the typical detail for thermal analysis. There are 6 types of details with the following configuration (Figure 1).

Three types of frame: non-thermally broken frame, thermally broken frame (with 24mm nylon thermal break strip), hidden frame; One type of vision glass: laminated Low-e IGU (6+1.52PVB+6Low-e+12A+6), aluminum spacer; Two types of spandrel glass: laminated monolithic glass (6+1.52PVB+6), laminated Low-e IGU (same as vision glass).

Thermal analysis results

The thermal analysis results by THERM simulation are as following (Figure 2)

Glass center temperature

Figure 3 shows the temperature indicator of glass center. Figure 4 shows the temperature of the inner pane glass. Figure 5 shows the temperature of outer pane glass. From the above figures, it can be found that the temperature of the outer and inner pane glass have little correlation with the types of frame and spandrel glass, mainly depend on the outdoor temperature and solar irradiance. It is also found that:

1) The maximum temperature for the inner pane glass of Low-e IGU is 37ºC