[TRNSYS-users] TRNFLOW : air supply problem

[mcdowell at tess-inc.com]

Arnaud - 

I think you need to understand some things about airflows
in Type56 before moving to TRNFLOW. 

A ventilation flow defined for a
zone in the Ventilation Type Manager is only flow into a zone. The flow
rate of this air stream can be constant or scheduled as defined in
TRNBUILD or defined as an input to the model and connected in Simulation
Studio. The temperature and relative humidity of the air stream can be
the outdoor conditions, constants defined in TRNBUILD, or inputs from
Simulation Studio. 

For flow between zones in Type56 you can define
coupling airflow rates in the zone manager. Again, these are flows into
the zone, so they need to be defined in both zones. 

TRNFLOW is adding
bulk airflow modeling to the thermal modeling. It may be necessary to
use in your case, but an understanding of the basic airflow in Type56
will be helpful in making your decision. 

Regards, 

Tim 

---
Timothy
P. McDowell
Executive Vice President
Thermal Energy System Specialists,
LLC
22 N Carroll St, Suite 370
Madison, WI 53703
608-274-2577

On
2013-04-10 10:17, Arnaud Candaele wrote: 

> Hi everyone,
> 
> I have a
little problem with TRNFLOW. I have a small house, in which I want to
bring fresh outside air in some rooms, and extract used air from wet
rooms. For this, I firstly used the "Ventilation Type" Manager to bring
air in my rooms.
> 
> My first question is : can I also extract air from
a room with the Ventilation Type, using a negative mass flow rate for
instance ? Or doesn't it make any sense, since from what I understood,
this type only brings air with outside conditions in the room, and
assumes the equivalent air volume is removed from the room.. (and going
"nowhere", so this would only act as a "gain" depending on incoming flow
energy)?
> 
> Second, also from what I understood : TRNFLOW can not be
superposed to this Ventilation Type Manager. I explain : In my case, I
use TRNFLOW and define cracks between each room and an external node at
constant pressure (I don't want to include wind effect for now), AND I
also use the Large Opening Type to represent doors between the rooms.
Does that mean I can't use the Ventilation Type Manager ? e.g. can I
supply 50m³/h in room1 with the ventilation type manager, while
simultaneously connecting this room1 with for example room2 with a large
opening link ? Or does the activation of TRNFLOW automatically cancel
the Ventilation Type ? Or maybe it doesn't cancel it but no relation is
established between the air supply and the rest of the TRNFLOW model ?

> 
> To summarize, my last and real question would be : how can you
model air supply/extraction in some rooms while using TRNFLOW ? Do we
have to create an auxiliary node with outdoor condition and link it with
a fan to the zone in which we want to supply air ? Isn't there a simple
way to just impose constant (or scheduled) air supply in a room while
using TRNFLOW ?
> 
> All these questions raised because I had some weird
comportment, and I thus tried to monitor air flow in some rooms.. and it
stays constantly at 0.
> 
> Thank you for your help,
> 
> Arnaud.
 
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