Tarray vs Irradiance Weighted Module Temperature

[tshaw26]

We are being asked to provide a modeled Irradiance Weighted Module Temperature for some projects that we are working on, and have a few questions that have come up:

- Is the Tarray that is showing in PVsyst the same as the Irradiance Weighted Module Temperature? If not, where can I go in PVsyst to get the information?

- The portfolio consists of several smaller projects, all located within a few miles of each other. Some of the sites consist of older modules that are about 3 years old. Because of this, we are incorporating a 3% LID loss, while the sites using the new modules do not have this loss calculated in. I have noticed after running the simulations that the sites using the new modules are showing almost 10 degrees cooler on the Tarray. Is this because of the lack of the LID loss, or does it have more to do with temperature coefficient?

Any insight that someone can provide would be greatly appreciated.

Thank you

[André Mermoud]

Sorry, we have just discovered an error in the TArray evaluation: the averages of TArray in Daily or Hourly values don't work correctly, as the operating time is not well registered.

If you want significant values of TArray, the only way is to analyze them in hourly values (in the CSV file).

This will be corrected in the version 6.50.

[abhipande9gmail.com]

We are also facing the same problem. We are using hourly irradiance-weighted module temperature values from weather file and hourly irradiance weighted module temperature values measured at site for temperature correction in Performance ratio for the site. However, some clients suggest that there is no need for using irradiance weighted Tarray values from PVsyst as these are already calculated using irradiance.

Please suggest if it is uncorrect to use Irradiance weighted module tempearture instead of direct Tarray values.