Following

Dear Teklehaimanot Zere

The yearly average of solar energy entering at the top of the Earth's atmosphere is around 1361 W/m2. The Sun's rays are attenuated as they pass through the atmosphere, leaving maximum normal surface irradiance at sea level on a clear day at around 1000 W/m2.

The minimum solar insolation needed to generate electricity is 100-200 W/m2, which is enough to power at least one lamp and fan.

Kind Regards

Qamar Ul Islam

Global horizontal irradiance (GHI) varies with latitude and time so for ground based measurements, the maximum value depends upon at least these two variables. Other factors that may vary the GHI include atmospheric turbidity, local albedo, near and far shadings etc. Locations on Equator receive highest GHI. Moreover, the data and time of the peak GHI depends upon location.

You may refer to NREL website https://www.nrel.gov/gis/solar-geospatial-data-tools.html for different data sets related to solar irradiance and other related data sets.

Furthermore, you can refer to different solar irradiance models e.g. ASHRAE Clear sky model for obtaining the maximum GHI at a location.

Regards

Arslan A. Rizvi

Dear Teklehaimanot Zere ,

welcome!

I could not understand your question. What do you mean by minimum and maximum threshold of the solar irradiance?

The solar irradiance is varying among the day and from day to day along the whole year. And it seldom repeats itself in an identically manner because of the random weather conditions and the sun activity.

Best wishes

Am sure the writer is referring to the minimum and maximum reading obtained in a day. As solar irradiance varies among the day and from day to day along the whole year. And it seldom repeats itself.

The solar irradiance value can not exceed the solar constant value of 1367 W/m^2 which is defined as the amount of solar light crossing the earth on a theoretical surface perpendicular to the Sun’s rays and at Earth’s mean distance from the Sun. So you can use this value as an upper threshold.

I do not think there can be a global minimum irradiance threshold, because such a minimum threshold is only relevant within the context of your application.

Thank you Chinedu. I read in a research paper recommending sun rise sun set or a solar elevation as a filtering criteria.