afiala634 Posted February 12, 2020 Share Posted February 12, 2020 Hi all, I'm working to import measured POA irradiance measurements into PVsyst version 6.8.3. Looking at the measured versus modeled data, I'm seeing a large discrepancy in both POA and GHI values, particularly around noon. I believe I've narrowed this down to an issue with how I'm inputting axis tilt when importing the custom ASCII file. If I enter the axis tilt as the negative of the system axis tilt is entered (i.e. entering in -2 during the file import orientation definition whereas the orientation is defined with a 2 degree tilt), this seems to produce well matching results between measured and modeled data. I'm hoping to understand why this is however. Does PVsyst require a 0 degree axis tilt to be most accurate in its transposition calculation?Thanks,Alec Link to comment Share on other sites More sharing options...
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