[TRNSYS-users] Further questions about weather data file and new component

[Cramer Silkworth]

Artemi,
 
I just realized that the shading only applies to windows, not an entire
facade. Also, I thought this problem through a little more and have a
different suggestion. I must not have had enough coffee last time...
 
If I understand what you're trying to do, it's actually pretty simple.
In TrnBuild, select your roof surface. Set the category as a BOUNDARY.
This kind of wall has no radiation on it (only EXTERNAL walls do), and
then you can select the boundary temp as user defined, then set up the
input from your special component. As far as I know, you cannot tell
trnsys that the surface temp of the roof or wall is anything in
particular, but you can tell it that the air outside of it is a certain
temperature. It's not a perfect solution but it might suffice.
 
The issue of negative radiations is solved by equations that are put
between type 109 and type 56. These check to see if the value is <0, and
if so, send only 0 to type 56, and not the negative value. I'm not sure
why such a check is not built into type 109 already, but whatcha gonna
do. Some example deck files include these equations I think, but if you
start from scratch you need to know to put them in yourself. They look
like this: output=max(input, 0). Thus if the input is <0, the output is
0, otherwise the output is the input.
 
The parameter is "locked" due to the way trnsys studio is set up to
handle different variations of the same type (109-user, 109-tmy, etc).
If you open your deck file in Notepad (or any other text editor), you
can see the 'real' code of the file. Find type 109, and you'll see how
the parameters are set up. Just change the value for the first parameter
and you should be all set. Save it and reopen in Simulation Studio.
 
I hope this helps,
-Cramer
 
 

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From: Artemi Spanaki [mailto:spanakiart at hotmail.com] 
Sent: Wednesday, January 21, 2009 6:24 AM
To: trnsys-users at engr.wisc.edu; techsupport at tess-inc.com; Cramer
Silkworth
Subject: Further questions about weather data file and new component



(This mail is sent to Matt Duffy, Cramer Silkworth and TRNSYS Users
List)

 

Dear Matt Duffy, Cramer Silkworth and TRNSYS users.

 

Thank you for your important advises. 

 

Your ideas about dealing with my additional component through the
building’s roof are quite helpful. I would like to ask the way to do it.
How can I define the inside of the wall, such as the drywall, and then
connect that to my component? How can I define that as a boundary wall
with an input temperature (from my roof component)? The TRNBuild
software has very limited options to do the above. I do have created the
roof temperature as an output of my new component and input of type 56,
but I am not sure that the software “understands” that this is the roof
temperature on the ceiling of the building?

 

From the other hand, Cramer Silkworth advises to block solar radiation
to the roof by saying that it's 100% shaded, or override the usual
horizontal radiation input and set it equal to zero. Additionally I can
say that the temperature "outside" this particular surface is equal to
an input. Through which software can I apply these opltions?

 

As far as it concerns the weather data reading and processing, when I
transform a component as type 109-user in order to make it similar to
the options of one of TRNSYS examples that is similar to my problem I
get errors (negative radiation in one or more orientation). If I copy
the components (type 109) from the example and paste it to my project I
don’t get these errors. The problem is that I cannot change the
parameter 1 of type 109 to 2 because it is locked. 

 

Best regards,



 

Artemi Spanaki


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