CSP Parabolic Trough Physical - SF HTF (Oil) Mass Flow Balance

  • Javier Pastoriza
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04 Nov 2022 11:19 #11654 by Javier Pastoriza
Dear community:

I've been trying to close the SF HTF (Oil) mass flow balance ("Field HTF mass flow rate total" = "TES HTF mass flow rate - field side of HX" + "Cycle HTF mass flow rate") but I continuously get inconsistent results. The Excel file shared illustrates the issue, the balance is presented in column AJ.

Any idea of what is going on? Thanks!

Javier Pastoriza.

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  • Paul Gilman
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07 Nov 2022 23:01 #11664 by Paul Gilman
Dear Javier,

Please see this related posts and let me know if it resolves your question:

sam.nrel.gov/component/kunena/forum-general/1036

Best regards,
Paul.

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  • Javier Pastoriza
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08 Nov 2022 06:02 #11667 by Javier Pastoriza
Thanks Paul for your answer.

I understand SAM uses iterative algorithms and convergence error are part of them, that is natural. However, my query still remains given the relative error magnitude, at time step level, I can see on the SF HTF mass balance calculated using the variables presented in my initial query. I would like to take it forward differentiating different operation scenarios if you allow me.

(1) SF Off + TES Discharging + Cycle On: min rel. error = 0% / max rel. error = 0%
(2) SF On + TES Discharging + Cycle On: min rel. error = -0.10% / max rel. error = 0.09%
(3) SF On + TES Idle + Cycle On: min rel. error = -0.08% / max rel. error = 35.54%
(4) SF On + TES Charging + Cycle Off: min rel. error = 0% / max rel. error = 94.24% (single time step)
(5) SF On + TES Charging + Cycle On: min rel. error = -4.60% / max rel. error = 33.35%

The relative error size makes me think we are facing something else than convergence errors. I could be missing or misinterpretating the problem.

Warm regards.

Javier Pastoriza.

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  • Paul Gilman
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09 Nov 2022 16:16 #11672 by Paul Gilman
Hi Javier,

Attached is an Excel file that shows the mass balance for the physical trough model.

Best regards,
Paul.

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  • Javier Pastoriza
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10 Nov 2022 05:37 #11675 by Javier Pastoriza
Thanks Paul, the balance works fine in the file you shared, no question. May I know the software version used to get this balance?

Nevertheless, the balance issue I have presented can be easily replicated when using the version 2018.11.11 just running the default case of the Trough Physical Model.

Javier Pastoriza.

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  • Paul Gilman
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12 Nov 2022 23:11 #11686 by Paul Gilman
Hi Javier,

I believe my colleague used SAM 2021.12.02 to generate the data in the Excel file.

Best regards,
Paul.

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