Has anyone did a simulation of electrochromic window?



Hi everyone,
If I want to model electrochromic window for daylight ,what battery I need to use to change the states of the window,the electrochromic window can change its optical data with a small voltage,which has 4 states all.
Can use the blind_states of this battery as the following image shows to change the window’s states.
I have tried it,but the result image of DA is striated and not varied gradually,like the picture shows.


@Fantasy ,

We would have to at least see where your sensor point is and what logic you are using on your blind_states to be of any help (it looks like you have set the states to always be tinted).

A sample file that re-creates your situation would also be very helpful.


Thank you chris.Can the blind_states control the glass window states besides the blind states.And can you give an sample file of electrochromic model.


@Fantasy ,

Here is a sample file that uses a 3-phase simulation and a sensor with an illuminance threshold to determine when blinds are down or up:

I would start from this file and swap out the clear and blinds BSDFs with BSDFs that represent the different tint states of electrochromic.


Thank you very much,chris.I have tried it based on your sample file,and the result is ok.Another question is that if the office have 3 windows and I want to control the states of the windows,can I use the following method to control them?

The first picture is the 3 windows and their states setting,the second is the states control.


@Fantasy ,

Using separate window groups is the correct way for individually controlling the electrochromic states of different windows.

Normally, you would generate the blind_states_ using and illuminance sensor, a threshold illuminance, and a logic for which electrochromic windows tint before others in order to meet the threshold. You can see this here in this example:


It looks like you have developed your own logic there using some python components (or you have some recorded data, perhaps?). That is also acceptable if it is what you are going for.


Thank you,dear chris.I have used EnergyPlus to simulate the build model and output the 3 windows’ states control schedule .csv file,and then I uses this csv file control schedule in honeybeeplus to do the daylight simulation like the aforementioned image.It is appeared that the example you showed did not control the electrochromic windows with several states,my electrochromic windows have four states(tint,clear and two medium states).


hi, i am doing some simulations similar with yours( my simulation is a blind with several states), and i want to know have you solved this problem now ? if you have solved now, could you tell me how to do that? Thanks !


Unfortunately, E+ does not natively support more than 2 states for a dynamic window so it is unfortunately something that is out of our hands. I know a couple of advanced E+ users who have used the Energy Management System (EMS) to model dynamic windows with more than one state but it is a steep learning curve to do so.


Dear @chris ,

Does Honeybee support all kinds of additional strings input?

In this discussion, I have implemented EMS into HB, but the results didn’t change simultaneously;