Re: [TRNSYS-users] Error simulation time step

Jeff,

Thank you.

Sinchote Keeratianant

M.Eng Energy&Technology Management Student

The Joint Graduate School of Energy and Environment (JGSEE)

King Mongkut's University of Technology Thonburi

Prachauthit Rd.,Tungkru

Bangkok 10140, Thailand

+(66)87-513-3561

cole_sin@hotmail.com

From: Jeff Thornton <thornton@tess-inc.com>
Sent: 18 July 2018 12:53 AM
To: TRNSYS users mailing list at OneBuilding.org
Subject: Re: [TRNSYS-users] Error simulation time step

Sinchote,

If you reduced your timestep to 1 minute and added pipes and you are still having convergence problems then it is very likely that you don't have things hooked up correctly or that your controls are aren't quite correct. We've modeled this type of system many times without convergence problems. You should research and try the TRACE command to help you figure out where the convergence problems are occurring and get hints as to what may be causing them.

Jeff

---
Jeff Thornton
President - TESS LLC
22 N. Carroll Street, Madison WI USA 53703
Office: (608) 274-2577  Fax: (608) 278-1475
www.tess-inc.com
E-Mail: thornton@tess-inc.com

On 07/17/2018 12:05 am, Sinchote Keeratianant via TRNSYS-users wrote:

Dear Jeff,

Thank you for your comment.

My modeling was made simulation every hour in the whole year.  I try to follow your idea, but unfortunately the system still show the same error.

Sinchote Keeratianant

M.Eng Energy&Technology Management Student

The Joint Graduate School of Energy and Environment (JGSEE)

+(66)87-513-3561

cole_sin@hotmail.com

From: Jeff Thornton <thornton@tess-inc.com>
Sent: 17 July 2018 1:29 AM
To: TRNSYS users mailing list at OneBuilding.org
Cc: Sinchote Keeratianant
Subject: Re: [TRNSYS-users] Error simulation time step

Would you control the real system that you are modeling to make decisions only once an hour? That’s what you are replicating by having an hour timestep. Add pipes, reduce your timestep to ~1 minute and you’ll start to see results that you’d see if you built this system.

Jeff

Sent from my iPhone

On Jul 16, 2018, at 1:58 AM, Sinchote Keeratianant via TRNSYS-users <trnsys-users@lists.onebuilding.org> wrote:

Dear TRNSYS users,

I use TRNSYS 18 for solar absorption cooling system as in Fig.1. While i set the simulation time step was 5 minutes, the system can simulate. However, when i changed the simulation time step into 30 minutes or 1 hour, the system cannot operate. The TRNSYS program show 2 error that below(as see in Fig.2)

1.)TRNSYS Messsage 203 ---> A convergence problem was encountered. Modification of the TOLERANCES control card may cure the problem.

2.)TRNSYS Messsage 450 ---> The maximum number of warnings allowed per simulation has been exceed. Please fix these warnings or increase the limit on the number of warnings allowed per simulation

Then i wonder that why i cannot set the simulation time step at any time. Does anyone have any idea or solution?

Thank you for your comment.

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  Figure 1

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Figure 2

Sinchote Keeratianant

M.Eng Energy&Technology Management Student

The Joint Graduate School of Energy and Environment (JGSEE)

+(66)87-513-3561

cole_sin@hotmail.com

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