[TRNSYS-users] SDHW

[Technical Support]

Jean,
 Without knowing what kind of warning you are getting, it is a bit
difficult to know what the cause of the problem might be. The two most
likely possibilities are

1. the time step might be too big. Only one control decision can be made
per time step. If you are using a 1 hour time step, then the pump will
turn on or turn off for an entire hour, which can often lead to
overheating or overcooling of the tank. Try to use a time step of about 5
to 15 minutes.

2. The component order might be incorrect (to change it, open the "control
cards" tool where you set the simulation start time, stop time and time
step) and move the components around in the list so that their order
matches the order in which the components appear in the real system.

If neither of those suggestions solves the problem, you might try to start
with the SDHW example in the ..\Trnsys16\Examples\SDHW directory and
modify it one piece at a time so that the changes in results make sense as
you make the system more and more like the one that you are trying to
model.

Kind regards,
 David





Technical Support Team
Thermal Energy System Specialists, LLC
2916 Marketplace Dr, Suite 104
Madison, WI 53719
techsupport at tess-inc.com

>----- Original Message -----
Subject: [TRNSYS-users] SDHW
Date: Tue, June 10, 2008 1:28
From: jean.goetschy at insa-strasbourg.fr

> Hi everybody,
>
> i'm new on this forum. I use Trnsys since 1 month now.
>
> I just want to make a simply SDHW system with a type 60d tank. This
> tank has just a heat exchanger (for the solar system) and a electrical
> resistance.
>
> For my SDHW, i use a single speed pump, a solar collector and the tank.
> My problem is when i connect the temperature exiting the heat
> exchanger to the pump. Then i have many "warning" (unit12,type60); i
> don't know why.
>
> I know that when i reduce the convergence and integration tolerance
> (0.1 for example) then i have less "warning" message but i find that
> those parameters have a big impact on the final results...
>
> So if someone have a solution...
>
> Thank you a lot
>
> Best regards Jean
>
>
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