modelling interstitial blinds in ventilated cavities

[Giovanni]

Hallo everyone,

I'm modelling a solar protection inside a ventilated facade.
The "Construction Database User Guide" proposes 2 methods for this:
1) Model the blind by using a fourth layer of glass but assigning the properties of the blind to this pane.
2) Model the cavity as a separate room. In this case the blind can be modelled in the normal way, by attaching an internal
shading device to the outer pane.

I see 2 main limitations.
- In method 1) I cannot control the shading device (i.e. I cannot assign any profile or rule to lower and raise the device).
- Both in method 1) and 2) I have no chance to use a shutter or a louvre, which have different transmission values depending on the solar radiation incident angle.

Why cannot I assign an external shading device to an "internal window"? Then using method 2 I could also include shutter and louvre.
Does the sun radiation have no more direction characteristics in VE once it passes trough the first glass pane?

I guess so far there is quite a lot of experience on this kind of simulation (as double skins are common nowadays). Can anyone comment on this?

Thanks,
regards
Giovanni

[myope]

This is interesting topic, I have same issue, the idea to solve such problem below, but please post your test result

Use additional surface for simulating device which you want to control:
1) create a box (room) same as the size of shading.
2) put 5 surface as 100% hole, keep 1 surface that corresponds to your shading only, assign 100% glass to this, the glass material will be 100% transparent, 0% reflex, just like air.
3) assign internal shading profile to this surface - you can because it's external glass. Profile only use as on or off (really regret for that point - >50% = on, <50% = off)
4) change your box to local shading then move it to right place.
5) create other box corresponds other shutter or louvre, create other profile for switching opening modes of shutter - by example, shutter closed 30%, closed 50%, each step need one more different box (size or place) and corresponding profile.
6) Verify and run.
7) putting result here

[PCully]

copying here Rosemary from the Tech Support team's response to this as well as it should add to the discussion

Unfortunately it is not possible to model the blinds in exactly the way you would like, i.e. on the inside of the inner glazing of the double skin facade. There are two methods for you to account for the blinds. In each case you should model double skin facade as a separate zone:

1) For the internal glazing, (between the room and the double skin facade), apply an extra layer of glass. For example if it was double glazing, make it triple glazing. Set the properties of the inner pane of glass to match the properties of the blind. The compromise with this method is that you must assume that the blinds are constantly down.

2) Apply the blind to the external glazing of the double skin facade. With the method you can control the blind however, they will block solar gain to the double skin facade void as well as the room, instead of just the room.

Phil

[PCully]

is it Lord Kevin or Lord Kelvin?