ERROR at trough storage time 0h

Hello,

When I use the technology option of CSP Parabolic Trough Physical Model and the financing option of Commercial PPA, the cases of (1) and (2) are calculated properly, but the case (3) cannot be calculated with the error message of the attached text file.

Case (1)
Full load hours of TES: 3, 6, 9, 12, and 15h
Solar multiple: From 1.0 to 4.0 with the increment of 0.25

Case (2)
Full load hours of TES: 0h
Solar multiple: 1.0, 1.1, and 1.2

Case (3)
Full load hours of TES: 0h
Solar multiple: More than 1.2

I can not understand the error message generated in the calculation of the case (3)
I would appreciate it if you could advise how the case (3) can be calculated?

Sincerely,

Hello,

It is hard for me to tell exactly what the problem might be without seeing your SAM file. Would you mind attaching Case 3 to your original message so that I can troubleshoot?

Best regards,
Paul.

Dear Paul,

Hello.
I attached the Case3 SAM file and climate text date.
Thank you for your cooperation.

Best regards,

Dear Suzuki,

Thank you for sending the file. The solar multiple represents the relative capacities of the solar field and power cycle under design conditions. For higher solar multiples, there are more hours during the year when the solar field thermal output exceeds the power cycles thermal input capacity. During those hours, SAM defocuses the collectors in the field to reduce the field's output. This requires an iterative algorithm that can fail in situations that require a lot of defocusing.

In the file you sent, I found that the simulations fail for solar multiples greater than 1.5, which suggests that given your design and location, the solar field should be smaller than that. Adding storage to the system would reduce the need for field defocusing.

Best regards,
Paul.

Dear Paul,

Thank you for your cooperation.
Although you mentioned that excessive defocusing of the collectors due to too much solar field area caused the failure of the calculation, I found that the calculation for the solar multiple greater than 2.25 with the storage hour: 0h could be converged.
I could calculate the cases for the solar multiple less than 1.25 and greater than 2.25.
Unfortunately, there was no local minimum value of LCOE in the range I could calculate. (Please see attachment: storage hour 0h_LCOE vs sm.png)
Therefore, the optimum value of solar multiple seems to exist between 1.25 and 2.25.
Could you advise how to find the optimum value in this situation?

Sincerely,

Suzuki