Why Does My Oovoo Say Signed In But Invisible

Electrochromic window glasses - shading at the push

Electrochromic windows are one of the many innovations being developed now for window glasses. These glasses with electrical voltage, the light transmittance of the glasses can be controlled. The advantage of this solution over the shutters is that the glass is colored blue and transparent, but still.

first How do these windows?

In the following graph of the structure of an electrochromic laminated glass shown.
The electrochromic laminated glass consists of two 4 mm thick laminated glass which, with transparent, conductive oxide coated (eg, fluorine-doped tin oxide) are. One glass is also shown with a tungsten oxide and the other disc with a so-called counter-electrode. Between these two glasses is a lithium-ion conductive polymer film. The two electrodes are connected to the circuit and can be activated by electrical impulses.

the electrodes are activated with electrical current, the lithium ions migrate from the tungsten and darken the glass. Thus, less light and less energy to pass through the glass. The entire process takes about 12 black-minutes.
As the winter in Central Europe Thermal protection can not be neglected, must also have a heat-resistant glass behind this electrochromic element can be built so that the entire window structure takes the following form.

As with "normal" heat-insulated windows, the space between the panes filled with a gas, so that an optimum thermal insulation can be achieved.

second Physical characteristics of electrochromic windows

The physical construction of these window values are summarized in the following table.

2-3-glazing triple glazing
U-value 1.1 0.5 W/m2K W/m2K
g-value (light) 36% 31%
g-value (dark) 12% 10%
light transmission (light) 50% 45
% light transmission (dark) 15% 14%

These figures clearly show that in the darkened state much less light and energy comes through the glass.

third Comparison of the energy transmission with normal glasses

Comparing the energy transmittance of electrochromic windows with normal windows, the result (purple: electrochromic windows, blue: normal window), the values shown in the graphic below.

The flux of electrochromic windows in winter compared with the values for normal windows. In summer, the energy transmission is much lower because of the built-in possibility of the shading and the smaller g-value. In order to make these windows a good review for summer heat protection and reducing energy consumption, because to be aired due to the lower summer heat input significantly less needs.



4th Comfort


The above example shows how these electrochromic glasses make the construction. The blue color is typical for electrochromic windows, the shading effect is clear. These windows are good for a shade of indirect sunlight. Less suitable are those windows for direct sunlight. these effects can be compared with the sunglasses, which also offers little protection for direct sun light. For this reason, can not yet dispense with the conventional sun protection, eg with shutters to the electrochromic windows, which of course significant effects on the economy has electrochromic window.




12th April 2009; Albert Müller

Sources used:
NZZ: 25 February 2009 "Light and shadow on a button"
website of the company EControl Glass & Co. KG ( www.econtrol-glas.de )
product catalog Pilkington "EControl-glass"