Hello everyone,
I am new to EnergyPlus, Daysim and Radiance. I am looking at the process of
converting EPW files to WEA files.
I am trying to understand the meaning of the minute field in an EPW file.
I read in
http://www.radiance-online.org/pipermail/radiance-general/2012-October/008968.html
that the minutes field does not relate to '*the time when the measurement
was recorded, but to the **recording interval'.*
The EPW Data Dictionary (
http://bigladdersoftware.com/epx/docs/8-3/auxiliary-programs/energyplus-weather-file-epw-data-dictionary.html#field-minute)
is not useful for understanding the meaning of the minutes field, as it
simply says:
* Field: Hour - This is the hour of the data. (1 - 24). Hour 1 is 00:01 to
01:00. Cannot be missing.
* Field: Minute - This is the minute field. (1..60)
If I take the EPW file for Gatwick Airport in London (
https://energyplus.net/weather-location/europe_wmo_region_6/GBR//GBR_London.Gatwick.037760_IWEC)
I see that its minute fields are set to 60 (hours and minutes in bold):
...
DATA PERIODS,1,1,Data,Sunday, 1/ 1,12/31
1991,1,1,*1,60*,...
1991,1,1,*2,60*,...
...
If instead I take the TMY3-based EPW file for Central Park in New York (
https://energyplus.net/weather-location/north_and_central_america_wmo_region_4/USA/NY/USA_NY_New.York-Central.Park.725033_TMY3),
I see that its minute fields are set to 0 :
...
DATA PERIODS,1,1,Data,Sunday, 1/ 1,12/31
1976,1,1,*1,0*,...
1976,1,1,*2,0*,...
...
Yet if I take the TMY2-based EPW file for Central Park in New York (
https://energyplus.net/weather-location/north_and_central_america_wmo_region_4/USA/NY/USA_NY_New.York.City-Central.Park.744860_TMY2),
I see that its minute fields are set to 0:
...
DATA PERIODS,1,1,Data,Sunday, 1/ 1,12/31
1976,1,1,*1,60*,...
1976,1,1,*2,60*,...
...
Can someone please explain in simple terms what the meaning is of the
minutes field?
Why is there a difference in the value of the minutes fields in the
IWEC-based EPW file for Gatwick (value is 0) and in the TMY3-based EPW file
for Central Park (value is 60)? What is the minutes field telling me about
the data?
Why is there a difference in the value of the minutes fields in the EPW
file for Central Park depending on whether it is TMY2-based (in which case
the value is 60) or TMY3 based (in which case the value is 0)?
Thank you in advance for your help,
Philip Schwarz