Detailed PV, temperature correction - heat transfer method

Dear Sir,
Considering Temperature Correction:
When selecting the NOCT method and observing the Data tables or Time series results, the cell (transient?) temperature seems wrong.

When selecting the heat transfer method and observing the Data tables or Time series results:
- The cell (transient?) temperature seems wrong.
- The steady state cell temperature is identical to the wetaher file ambient temperature (seems wrong).

Attached is the SAM file.
I'd much appreciate your assistance.
Gur Mittelman.

Hi Gur,

The "Subarray 1 Cell temperature (C)" and "Subarray 1 Cell temperature (steady state) (C)" are only different when you use a weather file with subhourly time steps. The values are the same for hourly simulations.

In my test using your file, the cell temperature is different from the ambient temperature:

 

I used a weather file from the NREL NSRDB for this test. Please share a copy of your weather file if you would like me to investigate further.

Best regards,
Paul.

Thanks Paul,
Attached is my .epw weather file.

Hi Gur,

I still don't see the results you describe. In my tests with your .sam file and .epw weather file, the ambient temperature, steady state temperature, and cell temperature are all different:

 

Best regards,
Paul.

Thanks Paul,
That data you show is for Jan 01.
But it seems that from Jan 04 and on, the cell temperature is identical to the ambient (selecting heat transfer method).

Best Regards,

Hi Gur,

I now see those results. Thank you for your patience.

There seems to be a problem with the "Array Dimensions" option of the Heat Transfer Method cell temperature model option. In addition to the cell temperature and ambient temperature values being the same after a certain date, you'll also note that the cell temperature is "NaN" (not a number) for some time steps. We'll investigate and fix that.

In the meantime, you can avoid the problem by using the "Module Dimensions" option of the Heat Transfer method, or by using the NOCT method.

Thank you for bringing this to our attention.

Best regards,
Paul.