internal windows and shading devices

[macpavee]

please tell me that there is a way to model the use of curtains and shutters on internal windows as well as external?

i am modelling a solar room for passive heating but need to include shutters and/or blinds/curtains on the internal windows, only i am not given this option in the constructions template (unless the window is external). does IES not consider internal windows as having curtains? -surely not....i must be missing something.

[Complex Potential]

That's an interesting one.

I have never tried to add blinds to internal glazing but, now you mention it, you are correct that the option is not there. The only advice I can offer is to adjust the transmittance (and hence the g value) of the internal glazing to approximate the impact of a curtain. The main issue with this is that a g value cannot vary like a blind can.

Perhaps one for the IES suggestion box?

[macpavee]

Well...at least i can stop scratching my head.

another option may be to rebuild the model with a second skin 'grafted' on (say about 1") in between the main room and the solar room on to which i can place doors as shutters. -at least for an outside option.
not possible for curtains inside the room though...ho hum

will put it in my growing list of suggestions to IES. ....love it/hate it

[Complex Potential]

I don't know how to tell you this but IES will not model solar gain transfer from one thermal zone to another if there is fresh air between.

Go figure

[macpavee]

HOLY £$%^

that explains a lot of my frustration with thermal mass also. especially trying to use concentrated storage within the space. i had noticed the lack of solar gain readings in vista and figured i would come back to it.

you have actually helped greatly pointing this out. not only on cutting down my work but in answering a significant point for my (slightly refocused) thesis question.
if you know of any more specific limitations inherent to IES (or simulation generally) with regard to it's inability to model passive solar design accurately please let me know.

-papers, links, authors.....

thanks

[Complex Potential]

I've sent you a private message although I have never found out how to look at "sent" messages on this forum to check if they have been delivered or not. I trust you saw it?

[macpavee]

hopefully you will see this CP

i think i have confused my self.

with regard to IES not modelling the solar gain between thermal zone if there is air in between.

i find in the calculation methods mention of suncast calculating the effect of radiant heat transfer through a number of subsequent layers which presumably means multiple thermal zones.
i do see that it would not be able to recognize a door opening and effectively removing a insulative layer, and even revealing a different material beneath be it glass or shiney for example. IES can only do that through the blind/shutter options in the constructions (but not for internal as mentioned)

so could you clarify for my addled mind the mechanism that makes IES fail in the way you suggest?
would this not mean the use of double skin facades is also a no no too?


all the best
m

[Complex Potential]

Hi Mac

IES will model solar gain transfer between CONNECTED zones fine (ie, internal glass on an internal wall) but the solar gain will not transfer if the zones have any sort of gap between them (ie, from external to external glass).

Hope this clarifies.

CP

[macpavee]

Thanks CP

that's clear now.