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 chemically deposited solar control coating and its experimental Verification are presented. A normal laminated glass is composed of two 3 mm glass sheets with a thin polymer layer between them. For the experimental verification, the coating used was a thin film of Cu(x)S added between the polymer layer and one of the glass sheets. A constant normal incidence of air mass 2 solar radiation was assumed. Conductive heat transfer within the glass sheets and convective and radiative heat transfer through the inside and outside are considered. Using the optical properties of glass, polymer and solar control coating, the redistribution of the absorbed component of the solar radiation and the shading coefficient (SC) are calculated as functions of the convective heat-transfer coefficient for the outside (h(o)). Variations of the theoretical inside glass temperature (T(g1)) for h(o) and SC for the solar absorptance (a) of the film varying from 0 to 0.9 are presented. For the array with 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 temperature 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) and 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.