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Re: [EnergyPlus_Support] Re: custom weather file with multiple years with the converter tool
Joe,
First off, the default for custom files is quite surly set to TimeHourOffset=0 (I tested it on data using both time stamp conventions). So you need to specify the offset to -0.5 an hour if you have solar data as -1:00-0:00 and need to let the WC tool calculate either DNI or DHI.
I've GHI and DNI on the full hour (instantaneous values, in practice same as -0:30-0:30). I "shift" the data half an hour backwards by linear interpolation and then calculate DHI with the TimeHourOffset=-0.5, thus getting the solar data as -1:00-0:00. This is not ideal as the interpolation does some smoothening on the solar data. Subtracting 7.5 from the longitude in the epw file doesn't seem as a robust solution, an alert user could change it back to the "right" longitude.
IDA-ICE treats all parameters including solar data as instantaneous and have 8761 or 8785 rows in an weather file. So when using e.g. your IWEC2 files users should shift the longitude by 7.5 degrees (I don't remember in which direction, but should be the opposite of what Energyplus need to do with files using the -0:30-0:30 convention). This issue is supposed to be dealt with in the upcoming 4.7 version of IDA-ICE.
Best regards,
Lukas
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Posted by: lukas.rokka@xxxxxxxxx
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