Solar control glazing
Solar control glazing has a coating that allows it to reduce the transmission of solar heat from the external environment while still permitting the optimal light transmission essential to ideal driving conditions. This type of glazing can reduce by over 25% the heat penetration in vehicles exposed to solar radiation, thus reducing the need for the use of fuel-hungry cooling systems. Dark-tinted glazing and switchable glazing also have solar control properties which can reduce the amount of solar heat entering the vehicle's cabin.
The last decade has seen significant improvements in the design and application of solar control glazings in vehicles. The major drivers are passenger comfort, minimising the degrading effects of the sun's radiation on interior trims and fabrics, and improving fuel consumption by lowering the load on the vehicle's air-conditioning unit. Additionally, vehicle styling is impacted by the choice of solar control glazing, from dark tints in the rear of the vehicle, to the differentiated colour of infrared reflective windscreens.
Solar radiation is partly reflected, partly transmitted and partly absorbed by a glazing, the degree of each depending on the glazing fitted. Most tinted glasses can selectively absorb the sun's energy, whilst glazings with specially designed coatings can be used to reflect solar radiation.
Absorbing Solar Control.
Green optimised solar absorbing glasses are providing significant improvement to occupant comfort. The products, designed for the European and North American markets respectively, reduce the heat entering through a vehicle's glazed area by roughly 20% when compared to a car equipped with standard tinted glass.
Due to vehicle safety legislation, requiring adequate light to provide clear driver vision, use of these dark tinted glazings is restricted to rear passenger compartments and to roof glazings.
The privacy glazing segment, originally developed for the North American market, now finds global applications. This grey glass has a low light transmission and an even lower transmitted energy value. It reduces the transmitted heat to the interior of the vehicle by approximately 65% in comparison to an optimised green glass used in the front of the vehicle. It also prevents more than 95% of ultraviolet radiation from entering the passenger compartment. This glass is increasingly the choice for SUVs and MPVs, in addition to being suitable for roof glazing applications.
One particular manufacture makes a green/blue portfolio of glasses that blends with the green front door glass to allow both a design choice and an improvement to solar loading. The glass has a light transmission in the range 26-45 % over a 3-5 mm glass thickness range. In a vehicle equipped with this technology the heat entering the rear of the vehicle is reduced by 45% when compared to that at the front of the car.