[TRNSYS-users] Slow model at boiler pressure of 10000kPa

Tue Aug 20 00:10:41 PDT 2019

Hi David

Apologies for late reply. I have 18.01.0000 version

That’s odd, just tried it again and doesn’t work. Not sure what’s happening. I took a snap shot of the exact settings I used, please see below

[cid:image004.jpg at 01D5577A.2FD4CEC0]

[cid:image005.jpg at 01D5577A.2FD4CEC0]

Best Regards,

Amir Nashed, PhD
Energy Engineer
Estate Management

UNSW SYDNEY NSW 2052 AUSTRALIA
E: a.nashed at unsw.edu.au<mailto:a.nashed at unsw.edu.au>
T: +61 2 9385 3401
M: +61 4 0597 9282
W: www.estate.unsw.edu.au<http://www.estate.unsw.edu.au/>
CRICOS Provider Code 00098G

[cid:image001.png at 01D2758A.1DD460C0]<http://www.unsw.edu.au/>

From: David BRADLEY <d.bradley at tess-inc.com>
Sent: Thursday, 15 August 2019 2:50 AM
To: TRNSYS users mailing list at OneBuilding.org <trnsys-users at lists.onebuilding.org>; Jeff Thornton <thornton at tess-inc.com>
Cc: Amir Nashed <a.nashed at unsw.edu.au>
Subject: Re: [TRNSYS-users] Slow model at boiler pressure of 10000kPa

Amir,

  Which v18 release is it? I tried with 18.00.0019 and 18.01.0000 and the simulations solves quickly. You can check the release number by opening the file trnsys.ini using a text editor such as Notepad. The steam quality is set to that odd value because the liquid is subcooled at your conditions and therefore the quality is undefined.

kind regards,

 David

On 08/13/2019 18:07, Amir Nashed via TRNSYS-users wrote:
Hi Jeff

Thanks for the email

I am using TRNSYS 18

If you want to replicate the issue, simply useType58 and put P=10000kPa and h=940 kJ/kg and you will get both issues: 1- super slow simulation 2- odd steam quality value of -1.5e38

Thanks

Best Regards,

Amir Nashed, PhD
Energy Engineer
Estate Management

UNSW SYDNEY NSW 2052 AUSTRALIA
E: a.nashed at unsw.edu.au<mailto:a.nashed at unsw.edu.au>
T: +61 2 9385 3401
M: +61 4 0597 9282
W: www.estate.unsw.edu.au<http://www.estate.unsw.edu.au/>
CRICOS Provider Code 00098G

[cid:image001.png at 01D2758A.1DD460C0]<http://www.unsw.edu.au/>

From: Jeff Thornton <thornton at tess-inc.com><mailto:thornton at tess-inc.com>
Sent: Wednesday, 14 August 2019 1:25 AM
To: TRNSYS users mailing list at OneBuilding.org <trnsys-users at lists.onebuilding.org><mailto:trnsys-users at lists.onebuilding.org>
Cc: Amir Nashed <a.nashed at unsw.edu.au><mailto:a.nashed at unsw.edu.au>
Subject: Re: [TRNSYS-users] Slow model at boiler pressure of 10000kPa

Amir,

Which version of TRNSYS are you using?  I know we identified and fixed an issue within the steam properties subroutine a few months back that might be the cause for your issue.

Jeff - TESS
Sent from my iPhone

On Aug 12, 2019, at 6:56 PM, Amir Nashed via TRNSYS-users <trnsys-users at lists.onebuilding.org<mailto:trnsys-users at lists.onebuilding.org>> wrote:
Dear TRNSYS users

For some reason all steam components at P=100 Bar (10,000 kPa) go very slow, whether it is a preheater, condensate pump..etc
The issue is not with the model, as I isolated the components, for example simulated type609 by itself and still did not work. . I believe the reason is the the Steam_Properties() subroutine as when I tried to use Type58 just by itself at the same steam properties, the same issues occurred. When I reduce the pressure to 9300 kPa, it works fine.

Inputs:
<image002.jpg>

Does anyone know how to solve that?

I can change the pressure, but I believe 100 bars for boiler pressure is pretty standard

Best Regards,

Amir Nashed, PhD
Energy Engineer
Estate Management

UNSW SYDNEY NSW 2052 AUSTRALIA
E: a.nashed at unsw.edu.au<mailto:a.nashed at unsw.edu.au>
T: +61 2 9385 3401
M: +61 4 0597 9282
W: www.estate.unsw.edu.au<http://www.estate.unsw.edu.au/>
CRICOS Provider Code 00098G

<image001.png><http://www.unsw.edu.au/>

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David BRADLEY

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Thermal Energy Systems Specialists, LLC

3 North Pinckney Street - suite 202

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