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Re: [TRNSYS-users] TRNBUILD/TRNFLOW air density

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@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/   

KlimaEngineering - Technologien für energieeffizientes Bauen und Nutzerkomfort in Gebäuden 
Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart

Amtsgericht Stuttgart - HRB 23347 / Steuernummer: 99073/00911 / USt-IdNr.: DE 152272639
Geschäftsführer: Matthias Schuler, Thomas Auer, Stefan Holst, Dieter Schnelle 

 

 

Von: TRNSYS-users [mailto:trnsys-users-bounces@lists.onebuilding.org] Im Auftrag von Arnaud Candaele via TRNSYS-users
Gesendet: Donnerstag, 6. Juli 2017 15:03
An: trnsys-users@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.