hello
I have three questions about theoretical computations in photovoltaics systems. I wonder if anyone skilled in this area could help me.
1-If the module efficiency written in a catalog is 18% and the calculated efficiency for the given module in specific weather conditions is 30%, does the calculated value make sense?
2-Is it possible to obtain negative values in the calculations done for short circuit current?
3-If the negative value is correct for the short-circuit current, according to the formula ( p =I_sc*V_oc*ff) will the output power also be negative? And If a few days of negative power is achieved in a month, how the average power is calculated? Is it ignored or the absolute values are used in the calculation?
Hello
Efficiency of solar panel is 15-20%.
It may rise upto 40% even 42% in some cases. The questions you asked may discuss by the article mentioned, because its based on increase PV efficiency.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://ieeexplore.ieee.org/abstract/document/7509317/&ved=2ahUKEwjGlc-ajIDwAhWTEMAKHbOVBe0QFjAAegQIAxAC&usg=AOvVaw0DeT3IanKiVVQxxEqTr2gi
You can install phase change material (PCM) behind PV in order minimize its temperature which will leads to increase efficiency.
Reza Alayi
سلام
وقتتون بخیر
با توجه به فرمول های مربوط به فتوولتاییک راندمان ماژول حدود دو برابر راندمان ثبت شده در کاتالوگ بدست می آید(در کاتالوگ ۱۸ و محاسبه شده ۳۱). به نظرتون این مقدار منطقی به نظر میرسه ؟ چون فقط شرایط آب و هوایی تغییر می کند.
و شرایط فقط برای یک ماژول در نظر گرفته شده است
با تشکر
Dear Zeashan H. Khan
Thank you very much for the references you mentioned.
Considering the formulas for the photovoltaic module, the value I have calculated for the efficiency is about twice one written in the catalog. Do you think this value seems reasonable? Because the only thing that has changed is the weather conditions (such as ambient temperature, radiation, wind speed) and there is only one module as same as the one in the catalog and nothing changes in it.
Dear Narjes Azizi ,
Hope you are well!
As for the first question,
The solar cell efficiency can not increase from 18 percent under the standard test condition to 30 percent under lower temperature condition.
It can so that the extrapolation formulas you used to calculate the solar cell parameters under other test conditions has limited validity range!
So, you have to elaborate your calculations.
Physically the short-circuit current increases slightly with temperature.
The open circuit voltage decreases with the temperature and the fill factor decreases with the temperature.
- The second question
The I-V curve of the solar cell appears in the 4th quadrant of the I-V plane.
So, It is negative. In the sense it is flowing to the positive pole of the solar cell.
This is its sense irrespective of the environmental conditions.
Changing the direction from being negative to positive is false. This means that the solar cell is no longer a source of electricity.
- The output power does not change its sign except operated out side the fourth quadrant. In this case it is no longer a solar cell but just a photodiode.
Please review the solar cells from the book:Chapter Solar cells and arrays: Principles, analysis and design
Best wishes
Dear Abdelhalim abdelnaby Zekry ,
It was really helpful. I got my answer.
thank you very much.
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