test_degradation.py

"""
Using pytest to create unit tests for pvdeg

to run unit tests, run pytest from the command line in the pvdeg directory
to run coverage tests, run py.test --cov-report term-missing --cov=pvdeg
"""

import os
import pandas as pd
import numpy as np
import pytest
import pvdeg
from pvdeg import TEST_DATA_DIR

PSM_FILE = os.path.join(TEST_DATA_DIR, r"psm3_pytest.csv")
weather_df, meta = pvdeg.weather.read(PSM_FILE, "psm")

INPUT_SPECTRA = os.path.join(TEST_DATA_DIR, r"spectra_pytest.csv")


def test_vantHoff_deg():
    # test the vantHoff degradation acceleration factor

    vantHoff_deg = pvdeg.degradation.vantHoff_deg(
        weather_df=weather_df, meta=meta, I_chamber=1000, temp_chamber=60
    )
    assert vantHoff_deg == pytest.approx(8.178, abs=0.01)


def test_iwa_vantHoff():
    # test the vantHoff equivalent weighted average irradiance

    irr_weighted_avg = pvdeg.degradation.IwaVantHoff(weather_df=weather_df, meta=meta)
    assert irr_weighted_avg == pytest.approx(240.28, abs=0.05)


def test_iwa_vantHoff_no_poa():
    poa = pvdeg.spectral.poa_irradiance(weather_df, meta)
    irr_weighted_avg_match = pvdeg.degradation.IwaVantHoff(
        weather_df=weather_df, meta=meta, poa=poa
    )
    assert irr_weighted_avg_match == pytest.approx(240.28, abs=0.05)


def test_arrhenius_deg():
    # test the arrhenius degradation acceleration factor

    rh_chamber = 15
    temp_chamber = 60
    I_chamber = 1e3
    Ea = 40

    poa = pvdeg.spectral.poa_irradiance(weather_df, meta)
    temp_module = pvdeg.temperature.module(weather_df, meta, poa=poa)

    rh_surface = pvdeg.humidity.surface_outside(
        rh_ambient=weather_df["relative_humidity"],
        temp_ambient=weather_df["temp_air"],
        temp_module=temp_module,
    )
    arrhenius_deg = pvdeg.degradation.arrhenius_deg(
        weather_df=weather_df,
        meta=meta,
        I_chamber=I_chamber,
        rh_chamber=rh_chamber,
        rh_outdoor=rh_surface,
        temp_chamber=temp_chamber,
        Ea=Ea,
        poa=poa,
    )
    assert arrhenius_deg == pytest.approx(12.804, abs=0.1)


def test_arrhenius_deg_no_poa():
    rh_chamber = 15
    temp_chamber = 60
    I_chamber = 1e3
    Ea = 40

    temp_module = pvdeg.temperature.module(weather_df, meta)

    rh_surface = pvdeg.humidity.surface_outside(
        rh_ambient=weather_df["relative_humidity"],
        temp_ambient=weather_df["temp_air"],
        temp_module=temp_module,
    )
    arrhenius_deg = pvdeg.degradation.arrhenius_deg(
        weather_df=weather_df,
        meta=meta,
        I_chamber=I_chamber,
        rh_chamber=rh_chamber,
        rh_outdoor=rh_surface,
        temp_chamber=temp_chamber,
        Ea=Ea,
    )
    assert arrhenius_deg == pytest.approx(12.804, abs=0.1)


def test_iwa_arrhenius():
    # test arrhenius equivalent weighted average irradiance
    # requires PSM3 weather file

    Ea = 40
    irr_weighted_avg = pvdeg.degradation.IwaArrhenius(
        weather_df=weather_df,
        meta=meta,
        rh_outdoor=weather_df["relative_humidity"],
        Ea=Ea,
    )
    assert irr_weighted_avg == pytest.approx(199.42, abs=0.1)


def test_iwa_arrhenius_poa():
    poa = pvdeg.spectral.poa_irradiance(weather_df=weather_df, meta=meta)

    Ea = 40
    irr_weighted_avg = pvdeg.degradation.IwaArrhenius(
        weather_df=weather_df,
        meta=meta,
        rh_outdoor=weather_df["relative_humidity"],
        Ea=Ea,
        poa=poa,
    )
    assert irr_weighted_avg == pytest.approx(199.42, abs=0.1)


def test_degradation():
    # test RH, Temp, Spectral Irradiance sensitive degradation
    # requires TMY3-like weather data
    # requires spectral irradiance data

    data = pd.read_csv(INPUT_SPECTRA)
    wavelengths = np.array(range(280, 420, 20))

    # convert to expected format
    spectra = data["Spectra"]
    spectra_df = pd.DataFrame(spectra.tolist(), index=spectra.index)
    spectra_df = spectra.str.strip("[]").str.split(",", expand=True).astype(float)
    spectra_df.columns = wavelengths

    conditions_df = pd.DataFrame(
        index=spectra_df.index,
        data={
            "relative_humidity": data["RH"],
            "temperature": data["Temperature"],
        }
    )

    degradation = pvdeg.degradation.degradation(
        spectra_df=spectra_df,
        conditions_df=conditions_df
    )

    assert degradation == pytest.approx(4.4969e-38, abs=0.02e-38)


# def test_hours_rh_above_85():
#     values = np.arange(0,100)
#     rh_linear_df = pd.DataFrame(values, columns=['rh'])

#     hours_above_85 = pvdeg.degradation._hoursRH_Above85(rh_linear_df)

#     assert hours_above_85 == 14


def test_wh_to_gj():
    gj = pvdeg.degradation._whToGJ(wh=1)

    assert gj == 3.6e-6


def test_vecArrhenius():
    poa_global = pvdeg.spectral.poa_irradiance(weather_df=weather_df, meta=meta)[
        "poa_global"
    ].to_numpy()
    module_temp = pvdeg.temperature.temperature(
        weather_df=weather_df, meta=meta, cell_or_mod="mod"
    ).to_numpy()

    degradation = pvdeg.degradation.vecArrhenius(
        poa_global=poa_global, module_temp=module_temp, ea=30, x=2, lnr0=15
    )

    pytest.approx(degradation, 6.603006830204657)