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How does pressure affect PVWatts output?
09 Feb 2024 23:00 - 09 Feb 2024 23:05 #12885
by Paul Gilman
Replied by Paul Gilman on topic How does pressure affect PVWatts output?
Hi Alejandro,
I tested PVWatts in SAM 2023.12.17, which runs the pvwattsv8 module with the attached test weather file that contains no pressure data.
A also ran your test script with the weather files you provided, and pvwattsv8 seemed to run with both weather files you provided:
The slight difference between the annual energy for the two cases is due to the code that calculates plane-of-array irradiance from the input DNI and DHI data: When the weather file does not include atmospheric pressure data, it sets the pressure to 1013.25 mb (sea level pressure).
Best regards,
Paul.
p.s. If you want to include an image in your posts on this forum, please attach the image as a file and then insert it into the message. Copying and pasting the image directly into the message does not work.
I tested PVWatts in SAM 2023.12.17, which runs the pvwattsv8 module with the attached test weather file that contains no pressure data.
A also ran your test script with the weather files you provided, and pvwattsv8 seemed to run with both weather files you provided:
The slight difference between the annual energy for the two cases is due to the code that calculates plane-of-array irradiance from the input DNI and DHI data: When the weather file does not include atmospheric pressure data, it sets the pressure to 1013.25 mb (sea level pressure).
Best regards,
Paul.
p.s. If you want to include an image in your posts on this forum, please attach the image as a file and then insert it into the message. Copying and pasting the image directly into the message does not work.
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