Consultation about HXN errors

[zasddsgg]

Hello, when I execute HXN, the following error will be reported, may I ask you how to solve it? Thanks for your help. Wish you a good day.

AssertionError: <HeatExchangerNetwork: HXN> 
Not equal to tolerance rtol=0.005, atol=0.001

Mismatched elements: 1 / 1 (100%)
Max absolute difference: 9.248
Max relative difference: 0.026

[zasddsgg]

Hello, could I trouble you take some time to look at this problem. Thanks for your help again.

[zasddsgg]

Hello, could someone help with this problem. Thanks for your help again.

[zasddsgg]

@yalinli2, @sarangbhagwat, Hello, could you help with this issue. Thanks for your help.

[sarangbhagwat]

Hi, @zasddsgg.

This error means there are likely units in your system with heat balance not satisfied. One of the reasons this can happen is if you have any heat exchangers in your system that have the 'rigorous' parameter set to False. To fix this, either set 'rigorous' to True, or (if the first solution is not viable for your implementation) add the heat exchanger (or parent unit) to a list past into the 'ignored' argument when creating your HXN object.

Let me know if you have further questions after trying this.

[zasddsgg]

a) @sarangbhagwat, Thank you for your advice. I have set all heat exchangers to rigorous=True, and added all heat exchangers to the codeHXN = bst.HeatExchangerNetwork('HXN', T_min_app = 10, ignored=lambda: [H1, H2, H3, H4, H5]), but the above error is still reported.

b) In order to ensure the accuracy of HXN, should all the heat exchangers be set to True, and would it be right to set to rigorous=False for some heat exchangers, and rigorous=True for the other heat exchangers?

c) If the heat exchanger is ignored (HXN = bst.HeatExchangerNetwork('HXN', T_min_app = 10, ignored=lambda: [H1, H2, H3, H4, H5])), is HXN still accurate, because HXN is the heat transfer of the heat exchanger.

[zasddsgg]

@sarangbhagwat, Hello, either set 'rigorous' to True, or add the heat exchanger to a list past into the 'ignored' argument do not solve the error.

[zasddsgg]

@sarangbhagwat Hello, I have tried some ways, but above error still reports. Could you help with this. Thanks a lot.

[zasddsgg]

@yoelcortes @yalinli2 @sarangbhagwat Hello, could you help look at this issue. Thanks a lot.

[sarangbhagwat]

Hi, @zasddsgg. To answer your questions: (a) I will need code from you to reproduce your error. I would suggest using the following template for your issues (the same as to post new issues for the BioSTEAM repo):

Describe the bug A clear and concise description of what the bug is.

To Reproduce A script or a text file that runs the code to reproduce the error.

Expected behavior A clear and concise description of what you expected to happen.

Actual behavior Full trace back, as text or a screenshot

Version

• PyPI version or github

Additional context Add any other context about the problem here.

(b) You may set rigorous=False for certain heat exchangers if you are sure there is no phase change happening in those exchangers.

(c) Yes, HXN results will still be accurate. The tool will simply be looking at the system as a whole except your ignored units, and putting together a network based on the remaining units.

[zasddsgg]

Thank you for your help and answer, the problem has been solved.