Turbine output control

h.johnson
Topic Author

19 Sep 2018 12:38 #6440 by h.johnson

Turbine output control was created by h.johnson

Hi SAM team,

I'm working on a LK script to change some simulation inputs and I'm wondering if it's possible to change the turbine output fraction to an array. In my script, it sets the 'ui_disp_1_turbout' to hourly values over a year with no error, but after simulating, it shows that the turbine output fraction does not follow the assigned array, and just stays as a single value. Attached is an image of part of the code.

If this is not possible, is there a way to best mimic an off grid CSP system to follow the demand profile?

Lastly, is there a quicker way to do element-wise multiplication/ division between arrays or with a single value in LK other than using a loop?

Thanks!
Holly

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pgilman

21 Sep 2018 21:24 #6441 by pgilman

Replied by pgilman on topic Turbine output control

Dear Holly,

The

ui_disp_1_turbout

input variable is a number with a single value, and is the turbine output fraction for Period 1. It is not possible to change the turbine output fraction on an hour by hour basis from LK. I'm not sure what happens when you set its value to an array -- it seems like you should get an error trying to set a number to an array.

A tedious way to do this might be to set the value of the turbine output fraction, run an entire simulation, extract the output data you need for the time step in question, then change the value of the turbine output fraction, run another simulation, etc.

LK does not have functions for array operations. If you plan to do that often in your script, you can write a functions for array multiplication/division.

Best regards,
Paul.

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Mohammed Alfailakawi

10 Jul 2022 13:04 #11238 by Mohammed Alfailakawi

Replied by Mohammed Alfailakawi on topic Turbine output control

Dear Mr. Gilman,

I am traying to multiply two arrays of a similar length and store the results in a third array in a LK script using the following loop but it does not work:

for (i = 0 ; i<26; i++)
{
OM_production_capacity_expenses = variable_costs * AEG ;
}

The error message says: access violation: expected numeric, but found array

The scripting reference does not mention much about array functions, and I saw your reply to Holly that a function of array multiplication/division must be written but I did not understand what exactly you mean.

Thanks in advance,
Mohammed

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pgilman

11 Jul 2022 23:28 - 11 Jul 2022 23:28 #11240 by pgilman

Replied by pgilman on topic Turbine output control

Hi Mohammed,

Section 4 of the LK Guide explains arrays. (A link to the document is available from SAM's Help system and from sam.nrel.gov/lk-script.html.)

Here is an example that might help:

analysis_period = get('analysis_period'); // years
production = get('cf_energy_net'); // kWh/year

cost = 0.5; // $

for (i=0; i<analysis_period; i++)
{
      expenses[i] = cost * production[i];
}

outln(expenses);

Best regards,
Paul.

Best regards,
Paul.

Last edit: 11 Jul 2022 23:28 by pgilman.

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Mohammed Alfailakawi

12 Jul 2022 12:56 #11245 by Mohammed Alfailakawi

Replied by Mohammed Alfailakawi on topic Turbine output control

Dear Mr. Gilman,

Thanks a lot for the reply, your suggestion worked pretty well when multiplying arrays that are called from SAM.

My apologies, I forgot to mention that I am trying to call arrays from CSV files and multiply them as follow:

path = 'C:/Users/Mohammed/Desktop/LCOE Calculation' + '/';

AEG = csvread (path+'AEG.csv')
variable_costs = csvread (path + 'variable M&O costs.csv');

for (i = 0 ; i<26; i++)

{
OM_production_capacity_expenses = variable_costs * AEG;
}
simulate ();

I have some difficulty understanding the message when writing the csvread function in the LK script window:
csvread(string:file[,table:options]):array or table.

Note:
arrays in the CSV files are in columns and of the same length.

Thanks a lot for your time and efforts.

Regards,
Mohammed

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Mohammed Alfailakawi

12 Jul 2022 16:32 #11247 by Mohammed Alfailakawi

Replied by Mohammed Alfailakawi on topic Turbine output control

I also forgot to mention that the problem seems in how the LK reads the data, as for instance if you see the following two examples of data called from SAM by a get finction:
electricity_purchase_price = [ 0, 53572.4, 55195.7, 56868.1, 58591.2, 60366.5, 62195.6, 64080.1, 66021.8, 68022.2, 70083.3, 72206.8, 74394.7, 76648.9, 78971.3, 81364.1, 83829.5, 86369.5, 88986.5, 91682.8, 94460.8, 97323, 100272, 103310, 106440, 109666 ]

while the data I call from a CSV file appears as follows:
variable_costs = [ [ 0 ], [ 3.5 ], [ 3.61 ], [ 3.72 ], [ 3.83 ], [ 3.94 ], [ 4.06 ], [ 4.19 ], [ 4.31 ], [ 4.44 ], [ 4.58 ], [ 4.72 ], [ 4.86 ], [ 5.01 ], [ 5.16 ], [ 5.32 ], [ 5.48 ], [ 5.64 ], [ 5.81 ], [ 5.99 ], [ 6.17 ], [ 6.36 ], [ 6.55 ], [ 6.75 ], [ 6.95 ], [ 7.16 ] ]

and that is despite the fact that the calling order I used is the following:
variable_costs = csvread (path + 'variable M&O costs.csv', {numeric = true});

Thanks again and apologies for any inconvenience.

Regards,

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