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Avoid usage of weather file location instead of IDF one

asked 2021-06-14 05:30:27 -0600

Johann Lo gravatar image

Is there any way to avoid the usage of the EPW latitude and longitude when the following error occurs?

   ** Warning ** Weather file location will be used rather than entered (IDF) Location object.
   **   ~~~   ** ..Location object=SITELOCATION
   **   ~~~   ** ..Weather File Location=Barcelona - ESP SWEC WMO#=081810
   **   ~~~   ** ..due to location differences, Latitude difference=[0.10] degrees, Longitude difference=[0.10] degrees.
   **   ~~~   ** ..Time Zone difference=[0.0] hour(s), Elevation difference=[68.17] percent, [12.85] meters.

I thought about modifying the latitude and longitude in the EPW file before running but I am rather looking for an IDF solution. What are the consequences of using a different latitude and longitude besides slightly different solar calculations?

Thanks Johann

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answered 2021-06-14 09:08:33 -0600

Not sure I totally follow, but why don't you edit the IDF to match the EPW?

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answered 2021-06-21 10:29:35 -0600

Johann Lo gravatar image

I am using E+ in a python script that writes automatically the building's position in the IDF with the latitude and longitude. But most of the time the latitude and longitude are slightly different from the EPW file and E+ returns the warning quoted above. It is no big deal, I was simply looking for an easy solution for avoiding this and wondering why E+ would be so "strict" concerning these parameters (already happens with a latitude difference of 0.15ª which would be less than 20km apart from the weather station).

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Do you want the building's location or the EPW location to be present in the IDF?

sashadf1 gravatar image sashadf1  ( 2021-06-21 12:05:47 -0600 )edit

How are you getting the Site:Location object field information? From a DDY file? I have noticed a few DDY/EPW mismatches, but most of the time they are the same (at least in my experience).

What about reading the EPW as a part of the script and writing the IDF using the exact values from the EPW?

bonnema gravatar image bonnema  ( 2021-06-22 07:34:39 -0600 )edit

answered 2021-06-14 08:52:25 -0600

lklawrie gravatar image

Don't attach a weather file for the simulation? Only the solar calculations in the design days will be affected, the solar values in the weather file will still be used.

Why do you want to use the one entered in the IDF?


FIBPSA, FASHRAE - free repository of climate data for building simulation Climate.onebuilding is a FREE service not supported by any outside organization or government agency.

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Asked: 2021-06-14 05:30:27 -0600

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Last updated: Jun 21 '21