Question

kg/m3 2.Please prove by numerical consideration that photovoltaics energy yeld is from thermal energy output for similar area and tilted angle. ron/ band

Answer 1

The global formula to estimate the electricity generated in output of a photovoltaic system is :

           E = A * r * H * PR ........ Equation 1

E = Energy (kWh)
A = Total solar panel Area (m2)
r = solar panel yield or efficiency(%)

Most solar panels are between 15% and 20% efficient, with outliers on either side of the range. High-quality solar panels can exceed 22% efficiency in some cases (and almost reach 23%!), but the majority of photovoltaic panels available are not above 20% efficiency.
H = Annual average solar radiation on tilted panels (shadings not included)
PR = Performance ratio, coefficient for losses (range between 0.5 and 0.9, default value = 0.75)

The Stefan-Boltzmann Law explains how much power the Sun gives off given its temperature (or allows scientists to figure out how hot the sun is based on how much power strikes the Earth in a square metre). The law also predicts how much heat the Earth radiates into space. The Stefan-Boltzmann law doesn't say anything about the wavelength of light emitted, that is described by the Plank radiation formula.

This law is expressed as:

P=eσT4​​​​​​ A ........ equation 2

where:

• P is the total power radiated (energy per unit time) per unit surface area
• A is the surface area
• e is the emissivity (how good of a radiator/absorber the object is). For most objects this is taken to be 1, although the Earth's atmosphere is an interesting exception.
• σ is the Stefan-Boltzmann constant.
• T is the temperature of the object expressed in degrees Kelvin

The total radiated energy increases as temperature is increased.

From above two equation 1 and 2 we can see the PR ratio is between .5 to .9 , default value is .75,also solar panel yeild r is between 15 to 20% ,so overall energy output is 1/4

The efficiency of a solar cell is determined as the fraction of incident power which is converted to electricity and is defined as:

Where:
Voc is the open-circuit voltage;
Isc is the short-circuit current;
FF is the fill factor and
η is the efficiency.

The input power for efficiency calculations is 1 kW/m2 or 100 mW/cm2. Thus the input power for a 100 × 100 mm2 cell is 10 W and for a 156 × 156 mm2 cell is 24.3 W