[TRNSYS-users] Cross flow ventilation

[Loic Tachon]

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 ?
> [image: image.png]
>  or through surface definition, adjacent coupling air flow (if the
> adjacent surfaces are not deleted) ?
>
> [image: image.png]
>
> 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.
>> [image: image.png]
>> 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 ?
>> [image: image.png]
>>
>>  or I put a coupling air flow (same that natural ventilation mass flow)
>> for the horizontal surface ?
>> [image: image.png]
>>
>> Thanks a lot.
>>
>> Best regards,
>>
>> --
>> *Dr. Loïc Tachon *
>> (+33) 6 7440-0536 (France)
>>
>>
>>
>> _______________________________________________
>> TRNSYS-users mailing listTRNSYS-users at lists.onebuilding.orghttp://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org
>>
>> --
>> ***************************
>> David BRADLEY
>> Principal
>> Thermal Energy System Specialists, LLC
>> 3 North Pinckney Street - suite 202
>> Madison, WI  53703 USA
>>
>> P:+1.608.274.2577d.bradley at tess-inc.com
>> http://www.tess-inc.comhttp://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:+1.608.274.2577d.bradley at tess-inc.com
> http://www.tess-inc.comhttp://www.trnsys.com
>
>

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