Photovoltaic Power Generation and its Applications
映照的近义词
Homework Assignment 1
Zehan QIN EEA11 2011010642
TASK 1
Photovoltaic conversion efficiency for different forbidden bandwidth
ASTM E-490
2000 ASTM Standard Extraterrestrial Spectrum Reference E-490-00
钙片的作用
In 2000, the American Society for Testing and Materials developed an AM
0 reference spectrum for u by the aerospace community. That ASTM
E490 Air Mass Zero solar spectral irradiance is bad on data from satellites, space shuttle missions, high-altitude aircraft, rocket soundings, ground-bad solar telescopes, and modeled spectral irradiance.
磨砂膏的正确使用方法ASTMG173
American Society for Testing and Materials (ASTM) Terrestrial Reference Spectra for Photovoltaic Performance Evaluation
The ASTM G173 spectra reprent terrestrial solar spectral irradiance on
a surface of specified orientation under one and only one t of specified
有关自律的作文
atmospheric conditions. The distributions of power (watts per square meter per nanometer of bandwidth) as a function of wavelength provide a single common reference for evaluating spectrally lective PV materials with respect to performance measured under varying natural and artificial sources of light with various spectral distributions.
Analys:
Spectral irradiance in outer space exceeds that of earth surface constantly from the graph, which can be explained by the reflection and absorption of the atmosphere. Irradiation with shorter wavelength has more loss than the longer owing to a higher refractive index.
Furthermore, AM1.5 spectral irradiation graph fluctuate more drastically and has obvious notched for certain wavelength. From my point of view, it is typical matters that absorb irradiation with such wavelength that result in such phenomenon.
2.Integrated spectral irradiance
The NREL website announced that the integrated AM0 spectral irradiance has been made to conform to the value of the solar constant accepted by the space community; which is 1366.1 W/m2.
For verification, I u the function “trapz” in MATLAB to recalculate the integration of total irradiation across wavelength. That result is 1365.2 W/m2, in correspondence to actual obrvation data.
With reliability of such method checked, we can get a trustful AM1.5 spectral irradiance data, 900.1 W/m2.
3.Conversion efficiency
Ideal conversion efficiency merely relies on the forbidden bandwidth and spectral irradiation.
For theoretical rearch, we can t following assumptions:
All photons with higher energy than the forbidden bandwidth can and only can generate one electron through ionization, while photons with
lower energy are not able to react.
Extra energy provided by the photon cannot be reud but heating up.
irradiation that comes to the surface of earth is more concentrated, though less in amount, eliminating the waste at both ends.
Again, noticeable notches appears on AM1.5 curve, in that the original spectral irradiation curve doesn’t run smooth becau of typical matters may influence certain wavelength’s photons.
TASK 2
统计员岗位职责
Laminated photovoltaic cell design under AM1.5
1.Finding the best method of combination is a constrained optimization
problem, aiming at receiving the greatest amount of energy by a PV array of the unit size. First of all, we need to t veral practical assumptions to determine our objective function.
⏹The laminated photovoltaic cell has two layers. Total irradiation equals
to the sum of either layer.
⏹The first layer material absorbs entire irradiation photons with energy
surpassing its forbidden bandwidth.
⏹The first layer material could only convert the same amount of energy
as its forbidden bandwidth from every photon, leaving surplus energy wasteful.
⏹Low-energy photons that do not react with the first layer lost its energy
to a certain extent. The loss rate will be defined later on.
⏹Low-energy photons that comes to the cond layer have the similar
performance as tho ionize the crystal in the first layer.
2.Calculate the conversion efficiency limit on the fixed loss rate of 20%
Giving that spectral irradiation is a function of wavelength, we can t two individual wavelength as independent variables, and integrated
irradiation as the dependent one.
Definition:
Wavelengtℎ1:x1; Wavelengtℎ2:x2;价值形式
Integrated irradiation:S
The objective function writes as follows.
S=∫s∙x
x1
dx
instantlyx1
0+∫s∙
x
x2
dx
x2
x1
琥珀图片We can u loop statements to calculate the maximum conversion efficiency under certain combination. Here shows the mesh graph and the contour graph.
From the graph, we can conclude that the peak appears at the center of the 2-D coordinates, approximately(0.7,1.4)which reprents a combination of Ge and GaAs, with a peak value of 556.9 W/m2 and 61.88% for conversion efficiency. This result perfectly matches the announced data
