Electrochromic Glass and Glazing Systems

Last Updated: 

Monday, September 11, 2017

Software/Versions Affected:

• COMFEN›5

It is now possible to model glass layers that change state depending on the state of an electric current (electrochromics).

Radiance Renderings: the program currently is not able to produce Radiance renderings for electrochromic glazing systems.

Glass Library

In the Glass Library, for each electrochromic layer, there are several associated datasets, one for each different "state" of the layer that was measured.

At the date of this Release Notes, there are two electrochromic manufacturers represented in the Glass Library, each with multiple products

• Sage Electrochromic
• Soladigm Electrochromic

In the List View, each electrochromic layer has only one record representing it, the "light" or "clear" state.

In the Detailed View, all the states that were measured are displayed.

Electrochromics will have at least 2 states, a light and a dark state. In addition, there can be any number of additional states associated with the layer, depending on how many states were measured and submitted to LBNL by the manufacturer. However, Energy Plus, which COMFEN uses to do the annual energy calculation, will only use the light and the dark states.

For example, the Soladigm layer shown below shows the data from 5 different measured states of the glass layer, based on the voltage applied to the glass.

Glazing System Library

A glazing system can be defined using one of the electrochromic layers by selecting the desired layer from the Glass Library, adding it to other layers, etc.

At the present time, the only control for Electrochromics is "Meets Daylight Illuminance". This can be set from the Controls tab.