[esp-r] Re: 2HX stratified tank model

Nicolas Kelly nick at esru.strath.ac.uk
Fri Jun 10 09:25:41 BST 2011


Thanks Marco, 

I managed to solve the problem - a pump attached to the solar collector had a flow rate 100 times higher than the default 'rated flow' figure - resulting in a huge, unintended heat gain to the circulating water - this led to instability in the solution and subsequent appearance of NaNs. I really must go into the code and put in a fix for this.

Nick

Ps how are you progressing with integrating phase change into the stratified tank model?

---------------------------------------------------
Nick Kelly BEng (Hons) MSc PhD PGCE FHEA
Energy Systems Research Unit
Mechanical Engineering
University of Strathclyde
e: nick at esru.strath.ac.uk
t: +44(0)141 548 2854
f: +44(0)141 552 5105
---------------------------------------------------


-----Original Message-----
From: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Marco Manzan
Sent: 09 June 2011 15:44
To: esp-r at lists.strath.ac.uk
Subject: [esp-r] Re: 2HX stratified tank model

Alle giovedì 9 giugno 2011, esp-r-request at lists.strath.ac.uk ha scritto:
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>    1.  esp-r does not simulate (A.Sdei at brighton.ac.uk)
>    2. Re: 2HX stratified tank model (Haddad, Kamel)
>    3. Re: 2HX stratified tank model (Nicolas Kelly)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Wed, 8 Jun 2011 16:50:12 +0000
> From: A.Sdei at brighton.ac.uk
> Subject: [esp-r]  esp-r does not simulate
> To: "esp-r at lists.strath.ac.uk" <esp-r at lists.strath.ac.uk>
> Message-ID:
> 	
<43AC8FF96AEAFA43B65D1EDF7FD1C1214F90C824 at BELLATRIX.university.brighton.ac
> .uk>
> 
> Content-Type: text/plain; charset="us-ascii"
> 
> Dear All,
> 
> I have reinstalled cygwin and ESP-r in my machine and I still cannot
> simulate. The simulation-integrated simulation window doesn't open. I can
> carry on all other tasks, change materials and results and analysis works
> just fine. Any idea about what I can do? Thank you in advance, kind
> regards.
> 
> Arianna
> 
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> ------------------------------
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> Message: 2
> Date: Wed, 8 Jun 2011 14:06:11 -0400
> From: "Haddad, Kamel" <Kamel.Haddad at NRCan-RNCan.gc.ca>
> Subject: [esp-r] Re: 2HX stratified tank model
> To: "Nicolas Kelly" <nick at esru.strath.ac.uk>,
> 	<esp-r at lists.strath.ac.uk>
> Message-ID:
> 	<D7DF89D88828894797A82B041984F1BE11D3AB33 at s0-ott-x1.nrn.nrcan.gc.ca>
> Content-Type: text/plain; charset="us-ascii"
> 
> Nick, Those would be here:
> 
> tester\test_suite\stratified_tank
> 
> Kamel
> ________________________________
> 
> From: esp-r-bounces at lists.strath.ac.uk
> [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Nicolas Kelly
> Sent: June 8, 2011 11:57
> To: esp-r at lists.strath.ac.uk
> Subject: [esp-r] 2HX stratified tank model
> 
> 
> 
> Does anyone have an example of a plant network featuring the 2HX
> stratified tank model? I'm having problems with the model generating
> NaNs at the moment and it would be useful to have a working system for
> comparison.
> 
> 
> 
> Regards,
> 
> 
> 
> Nick Kelly
> 
> 
> 
> 
> 
> Liathach, Beinn Eighe and Upper Loch Torridon
> 
> 
> 
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> ------------------------------
> 
> Message: 3
> Date: Thu, 9 Jun 2011 09:19:48 +0100
> From: Nicolas Kelly <nick at esru.strath.ac.uk>
> Subject: [esp-r] Re: 2HX stratified tank model
> To: "'Haddad, Kamel'" <Kamel.Haddad at NRCan-RNCan.gc.ca>,
> 	"esp-r at lists.strath.ac.uk" <esp-r at lists.strath.ac.uk>
> Message-ID:
> 	<1C6300D291585C479F60053DBF140E8A01393C6A3640 at E2K7-MS2.ds.strath.ac.uk>
> 
> Content-Type: text/plain; charset="us-ascii"
> 
> Hi Kamel,
> 
> Thanks, I checked this model out - however the tank is coupled to fixed
> flow, fixed temperature connections. My model has the tank coupled to
> variable flow, variable temperature sources. What I need to determine is
> whether my NaN's are due to a problem with my plant network (i.e. the data
> I've used or incorrect connections) or by a bug in the tank model.
> 
> Regards,
> 
> Nick
> 
> ---------------------------------------------------
> Nick Kelly BEng (Hons) PgC MSc PhD FHEA
> Energy Systems Research Unit
> Mechanical Engineering
> University of Strathclyde
> e: nick at esru.strath.ac.uk
> t: +44(0)141 548 2854
> f: +44(0)141 552 5105
> ---------------------------------------------------
> 
> From: Haddad, Kamel [mailto:Kamel.Haddad at NRCan-RNCan.gc.ca]
> Sent: 08 June 2011 19:06
> To: Nicolas Kelly; esp-r at lists.strath.ac.uk
> Subject: RE: [esp-r] 2HX stratified tank model
> 
> Nick, Those would be here:
> 
> tester\test_suite\stratified_tank
> 
> Kamel
> ________________________________
> From: esp-r-bounces at lists.strath.ac.uk
> [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Nicolas Kelly Sent:
> June 8, 2011 11:57
> To: esp-r at lists.strath.ac.uk
> Subject: [esp-r] 2HX stratified tank model
> Does anyone have an example of a plant network featuring the 2HX stratified
> tank model? I'm having problems with the model generating NaNs at the
> moment and it would be useful to have a working system for comparison.
> 
> Regards,
> 
> Nick Kelly
> 
> [cid:image001.jpg at 01CC2685.BB940E50]
> Liathach, Beinn Eighe and Upper Loch Torridon
> 
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> End of esp-r Digest, Vol 59, Issue 7
> ************************************

Hi Nick

I've been working a lot with the stratified 2HX tank and I don't think the 
problem is in this model. I had a lot of problems with instabilities and 
variable flow when coupling it with a solar collector. I experienced no 
convergence and NaN problems. 
I've been simulating a system with boiler and solar collector, both systems 
connected with pumps and ON-OFF controllers driven by tank temperature.
I could obtain a better stability by using a proportional controller for the 
pump serving the solar collector. 
Anyway I will send you a model for comparison.

Marco

-- 
 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _   
|Marco Manzan               Email: manzan at units.it      |        
|Tel:   (+39) 040 5583506   Fax  : (+39) 040  572033    |        
|Dipartimento di Ingegneria Meccanica e Navale          |        
|Universita' degli Studi di Trieste                     |        
|via A. Valerio 10, 34127 TRIESTE                       |        
|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|

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