Model thermochromic glazing

Hi everyone,

I am working with Honeybee to run an energy simulation of a very simple model created in Rhino.
The model is just a cube with one facade provided with thermochromic glazing.
How can I model this kind of glazing? Should I use a Radiance or an EnergyPlus glass material?

Thank you very much to anyone that could help me!!


Check this example.
For thermal you need to set the shadeCntrlType_ input for the HB_EPWindowShades component to 3 or 4 depending on which temperature you are interested. Of course also set the shadeSetpoint_ to the right value for you.

Hi Abraham,
thank you for suggesting me this useful example.
I saw that the input 3 and 4 of the shadeCntrlType correspond to outside and zone air temperature. However, the thermocromic glass I need to model modifies its behaviour according to the surface temperature of the glass itself (and in particular, the temperature of the coating layer which is applied in the inner side).
Unfortunately, none of the input is connected to the glass surface temperature.
Do you have any idea for obtaining such parameter?
Any suggestion to solve this issue is welcome!!

Thank you,

did you ever figure out a way to incorporate exterior surface temperature into your thermochromic analysis?

Also, general Honeybee_EP Window Shade Generator component question (@chris & @mostapha): is the EP switchable glazing analysis 2-state (no tint or fully tinted state) or multi-state where the numerous pseudo fenestration constructions will be created over a linear curve between no tint Point A and fully tinted state B?

I’m also thinking about this problem.

Is it possible to calculate the window’s surface temperature by solar radiation and air temperature? There is a component “Ladybug_surface hourly solar” which can give the suface solar radiation hourly. Then we can make a shade schedule manually to connect with shade generator.

But as I know, the window’s surface temperature also changes with the internal condition, especially the internal air temperature, so I’m not sure the method above is accurate.

@Yang @josh.greenfield

You can model the way you are looking for only with EMS through E+ or Honeybee

There are number of outputs that the default template of E+ does not include and thats the main reason they added EMS as an extra function for E+ to sense extra signals for actuating shading elements

my team was thinking more about this and we thought maybe a “double simulation loop” might work, where the surface temperature of glass was first found in simulation #1, then that data was used to come up with a thermochromic schedule and then fed into simulation #2.

my question still, does honeybee only model binary on/off tinting or will it model multiple states (10%, 20%, 30%, etc) when using the shading generator component??

Hi Josh,

I have checked the surface outdoor temperature in a simple box simulation. The result is somehow related to the glazing parameter. For example, when I change the SHGC from 0.5 to 0.2 (assuming from clear to tinting), the surface temperature drop down.
So in this “double simulation loop”, which parameter we should use in simulation #1?

@AMIRTABADKANI mentioned EMS yesterday, but honestly I know nothing about it. Not sure if I understand correctly, the problem might be sloved by adding codes in the simulation.
Since the simulation is done hour by hour, is it possible to make the glazing parameter changing with the surface temperature result of last hour? Also, the changing function can be set step by step, which can satisfy the “multiple states” requirement.

BUT, I don’t have any experience in coding. There will be a long long road. :rofl: :rofl: :rofl: