[TRNSYS-users] TRNBUILD/TRNFLOW air density

Arnaud Candaele via TRNSYS-users trnsys-users at lists.onebuilding.org
Tue Jul 11 04:12:07 PDT 2017


Thank you.

But in TRNFLOW then, how is density updated with temperature? What is the
mathematical relationship?

Thanks a lot,
Arnaud.

2017-07-11 10:45 GMT+02:00 Marion Hiller <Hiller at transsolar.com>:

> Arnaud,
>
>
>
> For the coupling of the models, the nodal airflow model and the thermal
> energy balance model, everything is based on mass flows.
>
> For the airflow model (TRNFLow) the density in an airnode varies whereas
> for the thermal model of Type56 the density doesn’t change. It’s defined in
> the dialog “properties”.
>
> I’m not aware the densities are available as outputs.
>
>
>
> Furthermore, if I try plotting the TRNFLOW output "ACHZ" for on zone in a
> very simple test model (external node --> duct --> zone --> fan --->
> external node), to get an idea of the volumetric flow rate, i got zero
> value (although other indicators, such as FLNEL show me coherent mass flow
> rate).
>
>    - In general, output 210 “ACHZ” should give an output. You may sent
>    your simple examples to your distributor and ask for further help.
>
>
>
> Marion
>
>
> *-----------------------------------------------------------------------------------------------------------------------------------------------------------*
>
> *Dipl.-Ing. Marion Hiller *
> *TRANSSOLAR Energietechnik GmbH *
> *Stuttgart - Munich - New York - Paris *
>
> *www.transsolar.com/ <http://www.transsolar.com/>*
>
>
> *KlimaEngineering - Technologien für energieeffizientes Bauen und
> Nutzerkomfort in Gebäuden  Transsolar Energietechnik GmbH, Curiestrasse 2,
> 70563 Stuttgart *
>
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> Schnelle *
>
>
>
>
>
> *Von:* TRNSYS-users [mailto:trnsys-users-bounces at lists.onebuilding.org] *Im
> Auftrag von *Arnaud Candaele via TRNSYS-users
> *Gesendet:* Donnerstag, 6. Juli 2017 15:03
> *An:* trnsys-users at cae.wisc.edu
> *Betreff:* [TRNSYS-users] TRNBUILD/TRNFLOW air density
>
>
>
> Hello,
>
> I'd like to know where I could find details about the assumptions taken in
> TRNBUILD/TRNFLOW to compute the air density is a room (or in a TRNFLOW
> link). None of the outputs give this information (if I'm not mistaken!),
> and all flow rates are expressed in kg/h.
>
> Furthermore, if I try plotting the TRNFLOW output "ACHZ" for on zone in a
> very simple test model (external node --> duct --> zone --> fan --->
> external node), to get an idea of the volumetric flow rate, i got zero
> value (although other indicators, such as FLNEL show me coherent mass flow
> rate).
>
> Can somebody help me on this subject?
>
> Best regards,
>
> Arnaud.
>
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