[TRNSYS-users] A lot of convergence warnings

[knut.erik.enerstvedt at niva.no]

Hello,

I have no experience with chilled ceilings, but as I understand the manual 
(chapter 6, page 47), the chilled ceiling layer has to be the first layer 
(inside surface) in a wall. Or, if you have an adjacent wall, it can also 
be the last one (inside surface of the adjacent zone).

I was hoping that someone else with more experience with chilled ceilings 
would see your posting and give a more helpful answer.


Best regards,
Knut Erik 

 




From:
Mavi Cambronero Vázquez <maviqnk at gmail.com>
To:
knut.erik.enerstvedt at niva.no
Cc:
trnsys-users at cae.wisc.edu
Date:
05/13/2010 05:38 PM
Subject:
Re: [TRNSYS-users] A lot of convergence warnings



Thanks for your answers.....

I´ve noticed that the problem is the chilled ceiling used. It´s the first 
time that I try to use it and I supose I didn´t succeed. I know how to 
create a chilled ceiling layer, but I´m not sure what are the following 
steps. What I did was integrate the new layer as the last one in a new 
wall. TRNBuild said to me that a wall with chilled ceiling can´t be 
external, boundary or internal, so the only option is that it is 
adjacent.... adjacent to the roof???So I created a new zone called roof! 
I´m a bit confused.
 
If someone could help me I´d be very grateful!
 
Thanks

 
2010/4/29 <knut.erik.enerstvedt at niva.no>

In addition to reducing time step length, I would try the following: 

- Check if there is sufficient thermal mass in your system (add pipes in 
fluid loops, for example). 
- Use controllers (such as Type 2) instead of equations (LT, GT and 
similar) when variables that can change from one iteration to the next are 
involved. 
- Place components in a "natural" calling order (controllers before 
controlled equipment, for example): Control cards->Component order: Click 
and drag the different components to order them. 
- Use an online plotter to check if there are any unrealistic output 
values (very high temperatures, for example). 

Best regards, 
Knut Erik Enerstvedt 




>You could change the simulation time step (in steps of 1/(2^n) so 1 hour, 
0,5 hour, 0,25 hour etc). You can find this by assembly -> component 
>order. 
  
>Good luck, 
  
>Mariëlle Nuchelmans 
  
  
>Hi, 
  
>What can I do when there are lots of convergence problems??? The same 
project has different warnigs because of that if the simulation >starts at 
3896 than if it starts at 0.... Does the option "Optimaze component order" 
work?? If I select that option other errors appear... :(

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