[TRNSYS-users] Cross flow ventilation

Tue Jan 17 00:49:58 PST 2023

Thanks Marion for this important information.

Best regards,

Le mar. 17 janv. 2023 à 09:16, Marion Hiller <Hiller at transsolar.com> a
écrit :

> Loïc,
>
> Please be aware that it isn’t enough to delete surfaces between airnodes
> in order to generate a radiative zone.
>
> Airnodes have to be moved in TRNBuild into one zone. ( see details in the
> building model manual. )
>
>
>
> I highly recommend to include virtual surfaces in SketchUp rather than
> deleting surfaces.
>
> Otherwise  the volume calculation give wrong numbers  if you export your
> model from TRNBuild to SketchUp and reimport it into TRNBuild.
>
> For the calculation arinodes have to be closed volumes!
>
>
>
>
>
> Kind regards,
>
>
>
> Marion
>
>
>
>
>
> Transsolar Software Team
>
> hotline at transsolar.com
>
>
>
> Transsolar
>
> Stuttgart | Munich | Paris | New York
>
>
>
> Transsolar Energietechnik GmbH | Curiestrasse 2 | 70563 Stuttgart | Germany
>
> CEO: Matthias Schuler, Thomas Auer, Stefan Holst, Dieter Schnelle
>
> Registered at Amtsgericht Stuttgart HRB 23347 | USt-IdNr.: DE 152272639
>
>
>
>
>
> *Von:* TRNSYS-users <trnsys-users-bounces at lists.onebuilding.org> *Im
> Auftrag von *Loic Tachon via TRNSYS-users
> *Gesendet:* Montag, 16. Januar 2023 19:02
> *An:* David BRADLEY <d.bradley at tess-inc.com>
> *Cc:* Loic Tachon <dr.loic.tachon at gmail.com>; TRNSYS users mailing list
> at OneBuilding.org <trnsys-users at lists.onebuilding.org>
> *Betreff:* Re: [TRNSYS-users] Cross flow ventilation
>
>
>
> Thanks a lot for your reply.
>
>
>
> Best regards,
>
>
>
> Le lun. 16 janv. 2023 à 17:58, David BRADLEY <d.bradley at tess-inc.com> a
> écrit :
>
> Loïc,
>
>  Sorry for misinterpreting your question. I think you do need to delete
> the adjacent surfaces and get one large radiation zone that includes your
> stack of airnodes. Then you use the "coupling between airnodes" popup to
> define the rate at which air moves from one of the air nodes to the other.
>
>  If you drew your building in SketchUp you can draw in the adjacent
> surfaces between the airnodes and assign them as the "virtual surface"
> category option (sorry I can't check the exact language of the option; my
> SketchUp install is giving me problems right now and I can't launch it to
> check). In any case if those "adjacent" surfaces are set as virtual then
> they won't be brought into the TRNBuild model and thus you won't have to
> delete them manually but will still have the integrity of the airnodes.
>
> kind regards,
>
>  David
>
>
>
> On 1/13/2023 11:27 AM, Loic Tachon wrote:
>
> Thanks for the answer, in my case I know the ventilation cross flow
> induced by the stack effect and I suppose that this flow cross all the
> zone.
>
>
>
> Do I need to delete the horizontal air nodes adjacent surface (surface
> inside the radiation zone) to get just one radiation zone ?
>
>
>
> If we know the flow between airnodes, is it better to put it via coupling
> between zones pop up ?
>
>  or through surface definition, adjacent coupling air flow (if the
> adjacent surfaces are not deleted) ?
>
>
>
>
>
> Thanks a lot.
>
>
>
> Regards,
>
>
>
> Le ven. 13 janv. 2023 à 16:56, David BRADLEY <d.bradley at tess-inc.com> a
> écrit :
>
> Loïc,
>
>   The best way to address airflow within a building is to couple your
> Type56 simulation either with TRNFlow or CONTAM (Type97). The basic idea is
> that you build a parallel model to your Type56 containing information about
> the airflow openings between the airnodes (a radiation zone can contain
> multiple airnodes, especially where there is an atrium like you have
> described). TRNFlow or CONTAM then take the air node temperatures as well
> as the wind speed and geometry of the building and determine the amount of
> air flow that results between the air nodes. Large horizontal openings are
> challenging because both TRNFlow and CONTAM treat air flow through a
> horizontal opening as unidirectional. Still, it is by far the most rigorous
> way of treating the situation.
>
> kind regards,
>
>  David
>
>
>
> On 1/13/2023 8:29 AM, Loic Tachon via TRNSYS-users wrote:
>
> Dear Trnsys community,
>
>
>
> I want to simulate the stack effect in a high room with high thermal gain.
>
>
>
> For this, I have 1 zone and 5 thermal air nodes in the z direction to get
> the temperature at several heights.
>
> How can I do this and avoid that TRNSYS see ceiling between the zone ? Do
> I need to delete the horizontal surface for zone 2-3-4 ? Or do I put mass
> less horizontal surface ?
>
>
>
> As Well, how do I do the cross flow ventilation ? Do I use the couple mass
> flow between zones ?
>
>
>
>  or I put a coupling air flow (same that natural ventilation mass flow)
> for the horizontal surface ?
>
>
>
> Thanks a lot.
>
>
>
> Best regards,
>
>
>
> --
>
> *Dr. Loïc Tachon *
>
> (+33) 6 7440-0536 (France)
>
>
>
>
>
>
>
> _______________________________________________
>
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>
> TRNSYS-users at lists.onebuilding.org
>
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>
> --
>
> ***************************
>
> David BRADLEY
>
> Principal
>
> Thermal Energy System Specialists, LLC
>
> 3 North Pinckney Street - suite 202
>
> Madison, WI  53703 USA
>
>
>
> P:+1.608.274.2577
>
> d.bradley at tess-inc.com
>
>
>
> http://www.tess-inc.com
>
> http://www.trnsys.com
>
>
>
>
> --
>
> *Dr. Loïc Tachon *
>
> (+33) 6 7440-0536 (France)
>
>
>
>
>
> --
>
> ***************************
>
> David BRADLEY
>
> Principal
>
> Thermal Energy System Specialists, LLC
>
> 3 North Pinckney Street - suite 202
>
> Madison, WI  53703 USA
>
>
>
> P:+1.608.274.2577
>
> d.bradley at tess-inc.com
>
>
>
> http://www.tess-inc.com
>
> http://www.trnsys.com
>
>
>
>
> --
>
> *Dr. Loïc Tachon *
>
> (+33) 6 7440-0536 (France)
>
>
>
>
>

-- 
*Dr. Loïc Tachon *
(+33) 6 7440-0536 (France)
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