Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I'm going to echo what Mike has written above about the basis for the DDY files, but expand on that to say what I think should be done for locations that are absent from the ASHRAE HOF, which is to calculate them from the raw data used to create the EPW files. In my opinion that is actually preferable and more methodologically consistent than using the DDYs from the ASHRAE HOF, since the periods of records as well as station location are often not the same. For example, if I'm using a typical year weather file created from the last 12 years, why should I use a DDY file that's from the last 30 years? For that reason, when I created the CZ2010 weather files for the California Energy Commission, I also calculated and provided the DDY files to go with them.
(warning: following note refers to commercial weather data products) This is also done for the ASHRAE IWEC2 weather files, i.e., they all come with DDY files calculated from the same long-term record, as well as any weather file from White Box Technologies.)
| | 2 | No.2 Revision |
I'm going to echo what Mike has written above about the basis for the DDY files, but expand on that to say what I think should be done for locations that are absent from the ASHRAE HOF, which is to calculate them from the raw data used to create the EPW files. In my opinion that is actually preferable and more methodologically consistent than using the DDYs from the ASHRAE HOF, since the periods of records as well as station location are often not the same. For example, if I'm using a typical year weather file created from the last 12 years, why should I use a DDY file that's from the last 30 years? For that reason, when I created the CZ2010 weather files for the California Energy Commission, I also calculated and provided the DDY files to go with them.
(warning: following note refers to commercial weather data products) This is also done for the ASHRAE IWEC2 weather files, i.e., they all come with DDY files calculated from the same long-term record, as well as any weather file from White Box Technologies.) Technologies. note: Joe Huang is the president of White Box Technologies, Inc.)
| | 3 | No.3 Revision |
I'm going to echo what Mike has written above about the basis for the DDY files, but expand on that to say what I think should be done for locations that are absent from the ASHRAE HOF, which is to calculate them from the raw data used to create the EPW files. In my opinion that is actually preferable and more methodologically consistent than using the DDYs from the ASHRAE HOF, since the periods of records as well as station location are often not the same. For example, if I'm using a typical year weather file created from the last 12 years, why should I use a DDY file that's from the last 30 years? For that reason, when I created the CZ2010 weather files for the California Energy Commission, I also calculated and provided the DDY files to go with them.
(warning: following note refers to commercial weather data products) This is also done for the ASHRAE IWEC2 weather files, i.e., they all come with DDY files calculated from the same long-term record, as well as any weather file from White Box Technologies. note: (note: Joe Huang is the president of White Box Technologies, Inc.)
| | 4 | No.4 Revision |
I'm going to echo what Mike has written above about the basis for the DDY files, but expand on that to say what I think should be done for locations that are absent from the ASHRAE HOF, which is to calculate them from the raw data used to create the EPW files. In my opinion that is actually preferable and more methodologically consistent than using the DDYs from the ASHRAE HOF, since the periods of records as well as station location are often may not be the same. For example, if I'm using a typical year weather file created from the last 12 years, why should I use a DDY file that's from the last 30 years? For that reason, when I created the CZ2010 weather files for the California Energy Commission, I also calculated and provided the DDY files to go with them.
(warning: following note refers to commercial weather data products) This is also done for the ASHRAE IWEC2 weather files, i.e., they all come with DDY files calculated from the same long-term record, as well as any weather file from White Box Technologies. (note: Joe Huang is the president of White Box Technologies, Inc.)
