THE THERMAL RESPONSE OF LAMINATED GLASS WITH SOLAR CONTROL COATING

A transient one-dimensional mathematical model allowing the prediction of the thermal performance of laminated glazing with and without chem ically deposited solar control coating and its experimental Verificati on are presented. A normal laminated glass is composed of two 3 mm gla ss sheets with a thin polymer layer between them. For the experimental verification, the coating used was a thin film of CuxS added between the polymer layer and one of the glass sheets. A constant normal incid ence of air mass 2 solar radiation was assumed. Conductive heat transf er within the glass sheets and convective and radiative heat transfer through the inside and outside are considered. Using the optical prope rties of glass, polymer and solar control coating, the redistribution of the absorbed component of the solar radiation and the shading coeff icient (SC) are calculated as functions of the convective heat-transfe r coefficient for the outside (h(o)). Variations of the theoretical in side glass temperature (T-g1) for h(o) and SC for the solar absorptanc e (a) of the film varying from 0 to 0.9 are presented. For the array w ith the highest solar absorptance of the solar control coating (alpha = 0.9), the decrease in T-g1 was from 49 down to 27 degrees C, a tempe rature drop of 22 degrees C as h(o) increases from 5 to 100 W m(-2) K- 1. The SC for the array with alpha = 0 is almost constant with h(o) an d close to unity, whereas for the array with alpha = 0.9, the SG drops by 62% from 0.58 to 0.22 as h(o) increases.