Hi, Hamed

You can check the following article you can find all equations:

Article A new method for evaluating nominal operating cell temperatu...

Regards

Mostafa

Hi Hamed,

You could use equations in the PDF

My dear friend, the formulae in DIN EN 60891 (VDE 0126-6) should do the job.

yes ,Jens Fröbel ,its best

Dear Hamed Hanifi

Take a look at this paper

Best regards

Article Analysis on the Features of NOCT and NMOT Tests with Photovo...

I am not sure that calculating the NOCT (nominal operating cell temperature) is so easily possible without having at least the measured reflection/transmission of the module.

Is that what you want to do or do you want to calculate the power at 800W/m2 and 40degC? The latter should be possible with the temperature coefficients and assuming linear Isc dependence of the irradiance.

Thanks Jens Fröbel and Abdellatif Bouaichi for sharing the information. To some extent it is difficult to use some equations provided but works in some cases for Pmax (according to the data given in datasheets).

Jan Haschke this is true! But have you tried to calculate the NOCT values given in the datasheets of manufacturers with the STC data given there? It never matches any equation! sometimes I come to a deviation of 1% and sometime 10%!

I suppose their data comes directly from Softwares such as PVSyst (which I am not sure how it calculates the NMOT and NOCT values).

Omar Hazem MOHAMMED Hadi Jabbar Alagealy Mostafa Ibrahim El-Shafie thanks for the information you shared with me. Unfortunately, the work were mainly research based, and I could not find an easy way, without using coefficients given in the equations to calculate the parameters.

Hamed Hanifi

No, I have never tried that.

I think such a calculation would only be possible if you knew the optical properties (-> heating) especially in the IR of the module.

I am not an expert on module measurements, but I would have thought the NOCT is measured under defined conditions?

Jan Haschke I am not sure why IR heating is required for NOCT but I suppose wind speed can be a significant parameter. Typically, IR has almost 15% of the total heat sources. NOCT is of course a defined condition of 800 W/m2, AM1.5g, Tambient=25°C and Wind speed of 1 m/s. At least a kind of simplified equation should exist to estimate the NOCT parameters, without using other coefficients given in the literature shared by other responders.

Hamed Hanifi Yes, heat source from 1200-4000nm is only slightly above 160W/m2, but given that the NOCTs of different modules are also not super large, I thought you were looking for these small differences. We calculated a difference of a few degrees based on the optics (of only cells, no modules) presented here: Poster Impact of the Infrared Response of Crystalline Silicon Solar...

I believe, it was Olivier Dupré at that time that did the calculation, the equation is given in the poster as well, but maybe you'll find more details in his other publications about temperature dependence of Si solar cells...

Dear Hamed,

To my knowledge, there are no direct link between temperature coefficients and NOCT. NOCT are experimentally measured and give an indication of the quality of the thermal design of the module for a specific couple of solar irradiance and mounting configuration.

For a detailed discussion, you might want to look at two sections of the book

"Dupré, O., Vaillon, R., & Green, M. A. (2017). Thermal Behavior of Photovoltaic Devices. Springer."

1.2 Predicting the Operating Temperature and Energy Yield of PV Installations

3.4.2 Revisiting the Definition of Nominal Operating Cell Temperature

Best,

Olivier