Different POA bifaciality gain % for Norway and USA

Ronald
Topic Author

21 Apr 2022 14:51 - 21 Apr 2022 17:35 #10851 by Ronald

Different POA bifaciality gain % for Norway and USA was created by Ronald

Hi, can someone help me to find the reason for the below pictures? I simulated parametric runs for different azimuths and two locations. The bifaciality gain is not similar.

...in-vs-tilt.png

Last edit: 21 Apr 2022 17:35 by Paul Gilman.

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Paul Gilman

21 Apr 2022 17:37 #10856 by Paul Gilman

Replied by Paul Gilman on topic Different POA bifaciality gain % for Norway and USA

Hi Ronald,

I would expect the array orientation to affect the bifaciality gain because it affects the size and timing of shadows between rows of modules in the array.

Best regards,
Paul.

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Ronald
Topic Author

21 Apr 2022 19:26 #10861 by Ronald

Replied by Ronald on topic Different POA bifaciality gain % for Norway and USA

Thanks for the quick reply. However, why there is a large gain between east and west for Skjetelien, Norway and there is no gain for Phoeniz, USA: I know that there will some gain difference for Norway but this is very large right?

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Paul Gilman

21 Apr 2022 23:42 #10862 by Paul Gilman

Replied by Paul Gilman on topic Different POA bifaciality gain % for Norway and USA

Hi Ronald,

Could you attach the .sam file and weather files you are using for this comparison?

Best regards,
Paul.

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Ronald
Topic Author

22 Apr 2022 07:36 - 27 Apr 2022 22:15 #10863 by Ronald

Replied by Ronald on topic Different POA bifaciality gain % for Norway and USA

File Attachment:

File Name: tmy_63.340...2016.epw
File Size:1,823 KB

File Attachment:

File Name: Compare.sam
File Size:1,561 KB

Last edit: 27 Apr 2022 22:15 by Paul Gilman.

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Paul Gilman

27 Apr 2022 22:51 - 30 Apr 2022 00:10 #10900 by Paul Gilman

Replied by Paul Gilman on topic Different POA bifaciality gain % for Norway and USA

Hi Ronald,

I think these results have to do with the data in your weather file.

Here are results from a parametric simulation I ran using the "S49 BiFa" case in your file with a weather file for a location in Alaska with a similar latitude to your weather file. It shows a similar bifacial gain vs tilt angle for azimuth = 90 and azimuth = 270:

Attachment bifacial-gain-vs-tilt-az-high-latitude-tmy2.png not found

The results with your EPW file confirm your observation below:

Attachment bifacial-gain-vs-tilt-az-high-latitude-epw.png not found

When I compare the DNI data for your file with the Alaska file, I see that the DNI data shows a tendency to be higher in the morning hours. I think that is consistent with the results showing that the irradiance on the back side of a west-facing array would increase more with the array tilt angle than for an east-facing array: