Min and max header flow rate

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cspchathu
Min and max header flow rate

Dear paul
I tried the exercise explained in the https://sam.nrel.gov/sites/default/.../sam-webinars-2014-parabolic-troug....
But it does not converge. the results are attached. Also I can't understand that why we use 16 instead of 46 (=8*5.75). In the Webinar, the logic is explained. But what will be the highest value of Nsca, where we apply that logic? or is the maximum value of Nsca 16 (l'=2)?

I want to find the best solar collector which gives the best PPA(LCOE). To find that I am trying to do this exercise for other collectors too. i.e. I am considering the area of each collector in the SAM library. the excel sheet is attached here with. Then I simulate SAM file for each collector separately.
Have I done any thing wrong here?
Is there any method to find the best collector instead of the method what I am trying.

Then I tried the method explained in the "Technical Manual for the SAM Physical Trough Model,Michael J. Wagner and Paul Gilman".
The guess value calculated using Eq.2.15 (page 13) can be used as the current iteration value. But how do we decide the mass flow rate in the previous iteration, T'(loop,out) and T (loop,out) at the first iteration step. I tried to combine eq.2.10, 2.11, 2.26, and 2.13 with this. But I could not find a way. Please help me on this.

Some of SAM files, Weather data for Hambanthota, Sri Lanka and the excel sheet are attached here with.

cspchathu

hello,
I prepared excel sheet to calculate minimum and maximum loop flow rate. I followed the guidance given by the webinar. Can any one check this and give your idea on this. the excel sheet is attached in the previous post,

cspchathu

Hello,
did any one check this out? can anyone help me on this?

Paul Gilman

Hello,

It is not clear what you mean by "it does not converge." The results in the spreadsheet you attached seem to make sense.

The components in SAM's libraries are not necessarily useful for determining the “best” collector and receiver to use in a given application. You should be able to get information about expected optical errors, tracking errors, and other properties from the equipment manufacturers. They will also know the cost, which is obviously going to be one of the most important factors. The options in the library are useful as a reasonable starting point. From there you can understand general trough behavior as weather conditions, TES, and power cycle designs change and explore how changing design field parameters can affect performance.

Best regards,
Paul.

cspchathu

Hi,
I did a parametric analysis using SM, NFS (nos of field subsections), PPA price,and TES. a summary of the results are attached herewith. My understanding is, if the NFS, SM, and TES are not changed, the LCOE cannot be changed. am I correct? but according to the results, it changes when the PPA price changes. Please give me the reason/s. this can happen due to involving of many iterations. is that the reason?

Thank you,

Paul Gilman

Hello,

If you have chosen the Specify PPA price option on the Financial Parameters input page, the LCOE is likely to change with the PPA price, even if you do not change any other inputs. That depends on your other assumptions. For example, if you use the sculpted debt option to calculate the size of debt based on the cash available for debt service, then the debt costs will vary with the PPA price because available cash depends on revenue. Also income tax liability is included in the LCOE calculation, and that depends on revenue.

If you use the Debt percent option for debt sizing, set all reserve accounts to zero, set state and federal income tax to zero, and remove any production-based incentives, then you should see that the LCOE remains constant as you vary the PPA price.

Best regards,
Paul.

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