[TRNSYS-users] Detailed radiation model

[Łukasz Wątły]

Dear Christoph,

Thank you very much for your reply. Finally, I have checked the surfaces
and I can perform the simulations without any error.

However, I would also like to ask how I could obtain the mean radiant
temperature of the 3 airnodes in the model I described in the previous
email. In the manual (chapter 5.2.4.12 Radiation Modes) it is written that
the longwave radiation distribution is available only for thermal zones,
not airnodes - this might justify the reason why I got the same values for
different airnodes.

Thus, do you know if there is the way to overcome this problem?

I would be grateful for any hints.

Kind regards,
Lukasz

2018-07-02 10:40 GMT+02:00 hotline via TRNSYS-users <
trnsys-users at lists.onebuilding.org>:

> Dear Lukasz,
>
>
>
> As the error says, is your building geometry not closed or not convex
> (Manual 5-Multizone, 5.2.7.12. Zone Radiation Modes). This problem can’t be
> caused by your virtual surfaces.
>
> Please make sure that your building is convex and closed!
>
>
>
> Best,
>
> Christoph
>
>
>
> *Von:* TRNSYS-users [mailto:trnsys-users-bounces at lists.onebuilding.org] *Im
> Auftrag von *Lukasz Watly via TRNSYS-users
> *Gesendet:* Freitag, 29. Juni 2018 09:42
> *An:* TRNSYS users mailing list at OneBuilding.org <trnsys-users at lists.
> onebuilding.org>
> *Cc:* Łukasz Wątły <lukaszwatly92 at gmail.com>
> *Betreff:* [TRNSYS-users] Detailed radiation model
>
>
>
> Dear All,
>
>
>
> I have desgined in SketchUP a single thermal zone with 3 airnodes placed
> on different heights (*10*, *60*, *110* cm). I used a *Virtual Surface*
> option to model the surfaces which, after exporting them to TRNBuild, could
> dissapear.
>
>
>
> In my simulation of the zone, I would like to obtain three values of
> Tairnode, Toperative and mean radiant temperature for each airnode.
> Unfortunately, when I perform simulation in TRNSYS, all three values of
> mean radiant temperatures are the same. This I did with the radiation model
> set to *standard*.
>
>
>
> When I am trying to use the *detailed* radiation model, I got two error
> informations:
>
>
>
> *-* ==== zone GROUND_FLOOR_10... ... ERROR in summing view factors of
> surface 4. Please check geometry!!!.
>
>
>
> *-* Error while creating VFM file.
> +++ Note: Zones have to be convex and closed volumes.
>           Surfaces must have an outwarding normal.
>
>
>
> This causes the situation that I am unable to open the .vfm file in TRNSYS
> and cannot get the mean radiant temperature values.
>
>
>
> I assume that the problem is caused by the fact that my model might not be
> a closed volume, due to the virtual surfaces I have created in SketchUP. So
> my question is, is there another way to get the MRT values for each
> airnodes separetely?
>
>
>
> The view factor of *surface 4* is set to 0.5 automatically, as it is one
> of the vertical walls.
>
>
>
> Thank you in advance for your help.
>
>
>
> Kind regards,
>
> Lukasz Watly
>
>
>
> _______________________________________________
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> TRNSYS-users at lists.onebuilding.org
> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org
>
>
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