Problem 2.4

Fundamentals of Solar Cells and Photovoltaic Systems Engineering

Solutions Manual - Chapter 2

Problem 2.4

Using the tabulated data provided in the online repository of this book, estimate the UV content (280–400 nm) and the total irradiance in the extraterrestrial reference spectrum AM0, the global reference spectrum AM1.5G, and the direct reference spectrum AM1.5D.

We will use the package pandas to handle the data and matplotlib.pyplot to plot the results

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

We start by importing the data.

datafile = pd.read_csv('data/Reference_spectrum_ASTM-G173-03.csv', index_col=0, header=0) 
datafile

	AM0	AM1.5G	AM1.5D
Wvlgth nm	Etr W*m-2*nm-1	Global tilt W*m-2*nm-1	Direct+circumsolar W*m-2*nm-1
280	8.20E-02	4.73E-23	2.54E-26
280.5	9.90E-02	1.23E-21	1.09E-24
281	1.50E-01	5.69E-21	6.13E-24
281.5	2.12E-01	1.57E-19	2.75E-22
...	...	...	...
3980	8.84E-03	7.39E-03	7.40E-03
3985	8.80E-03	7.43E-03	7.45E-03
3990	8.78E-03	7.37E-03	7.39E-03
3995	8.70E-03	7.21E-03	7.23E-03
4000	8.68E-03	7.10E-03	7.12E-03

2003 rows × 3 columns

datafile.drop(datafile.index[0], inplace=True) #remove row including information on units
datafile=datafile.astype(float) #convert values to float for easy operation
datafile.index=datafile.index.astype(float) #convert indexes to float for easy operation

We start by calculating the total irradiance AM0, AM1.5G and AM1.5D.

for spectra in ['AM0', 'AM1.5G', 'AM1.5D']:
    irradiance=np.trapz(datafile[spectra], x = datafile.index)
    print('Total irradiance in ' + spectra + ' = ' + str(irradiance.round(1)) + ' W/m2')

Total irradiance in AM0 = 1348.0 W/m2
Total irradiance in AM1.5G = 1000.5 W/m2
Total irradiance in AM1.5D = 900.2 W/m2

We can also plot the three spectra

plt.plot(datafile, linewidth=2, label=datafile.columns)
plt.ylabel('Spectral irradiance [$W·m^{-2}·nm^{-1}$]')
plt.xlabel('Wavelength [nm]')
plt.legend()

<matplotlib.legend.Legend at 0x7fe9f97646d0>

We calculate the UV content in AM0, AM1.5G, and AM1.5D.

index=datafile.index<=400
for spectra in ['AM0', 'AM1.5G', 'AM1.5D']:
    irradiance=np.trapz(datafile[spectra][index], x = datafile.index[index])
    print('UV irradiance in ' + spectra + ' = ' + str(irradiance.round(1)) + ' W/m2')

UV irradiance in AM0 = 102.8 W/m2
UV irradiance in AM1.5G = 46.1 W/m2
UV irradiance in AM1.5D = 30.5 W/m2