Different Values: SAM and PySam

Samuel
Topic Author

27 Jun 2022 12:21 #11186 by Samuel

Different Values: SAM and PySam was created by Samuel

Hello, I'm currently using PySAM (Pvwattsv5) and I'm having different output values than SAM (2018.11.11) with no financial model using the

File Attachment:

File Name: Farol.csv
File Size:395 KB

in attachment. By SAM I generated the Python code (PySSC) and in it I have the same output values as the application, but using the same input values of the code generated in PySAM I having values are a little different.

Output SAM:

Output PySSC (genered code):

Output PySAM:

PySAM Code:

Code:

﻿import PySAM.Pvwattsv5 as pv

system_model = pv.new()

systemResource = {
    'solar_resource_file': r'C:/SAM/2018.11.11/solar_resource/Farol.csv',
}

AdjustmentFactors = {
    'constant': 2.49,           #Ajuste de perda constante
}

systemDesign = {
    #Parametros do Sistema
    'system_capacity': 1333.3299560546875,    #Capacidade
    'module_type': 1,                         #Tipo de Modulo (1 - Premium)
    'dc_ac_ratio': 1.3333300352096558,
    'inv_eff': 97,                            #Eficiencia do Inversor (%)

    #Orientacao
    'array_type': 0,                          #Tipo de Montagem (0 - Fixed Open Rack)
    'tilt': 20,                               #Inclinacao (graus)
    'azimuth': 0.0,                           #Azimuth (graus)
    'gcr': 0.40000000596046448,                              #Ground Coverage Ratio

    #total dc power loss
    'losses': 11.424985885620117
}

system_model.SolarResource.assign(systemResource)
system_model.SystemDesign.assign(systemDesign)
system_model.AdjustmentFactors.assign(AdjustmentFactors)

system_model.execute(0)

print(system_model.Outputs.capacity_factor)

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Paul Gilman

18 Jan 2023 17:56 #11841 by Paul Gilman

Replied by Paul Gilman on topic Different Values: SAM and PySam

Hi Samuel,

This relatively small difference is probably due to values being passed to PySAM having more digits to the right of the decimal point than the SAM inputs.

Best regards,
Paul.

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