20 August 2009

Green is the Greenest Color

Green wing by A Hermida

Ever wonder why so many buildings have green glass? I learned why today during a lunch presentation by Pilkington glass. It turns out that green offers the optimum solution for maximizing high light transmission with low solar heat gain. As you can see in the graph below, clear glass offers the highest light transmission (lets more light in), but it also is the highest in solar heat gain (room heats up). This would be desirable for buildings in the north where the climate is primarily cold. But for buildings in the south where the climate is primarily hot, less solar heat gain would be desirable.

Spectral Graph of Solar Energy

For some reason green is high in visible transmission, but the lowest in heat gain. The narrow band of wavelengths between 380 nm and 780 nm of the solar spectrum is visible to the eye. This represents the light transmission coming through the glass. Beyond this is Solar Infrared wavelengths. Infrared energy is what we experience in the form of heat every day. It lies between the visible and microwave sections of the electromagnetic spectrum. This represents the amount of solar heat gain through the glass.

BYU library by sudweeks

222 S Main in Salt Lake City by Tmac


Suzanna H. said...

Question: My grandparents have 'green glass' and with all its benefits, one thing they can't do is grow plants in their house. The windows don't let in the right kinds of UV rays. Is all green glass like this?

Patrick said...

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