[Bldg-sim] Revised TMY3 Weather Files now available on the Web

[Joe Huang]

Wet-bulb is not generally measured in weather stations, but can be derived from other 
measured climatic variables, such as dry-bulb temperature, dew-point temperature, and 
atmospheric pressure.  Unfortunately, the derivation requires several equations and 
trial-and-error iteration (see Chapter 1 of the ASHRAE Handbook of Fundamentals).  If you 
don't relish writing a script or program to do this, you can look at the unpacked DOE-2 
format (*.FMT or *.FMTM)  of the weather file, which does contain the calculated wet-bulb 
temperatures in the first data column (see attached sample snippet).  However,  you will 
need a utility Fortran program wthfmt2.f or wthfmt3.f  to convert the packed (*.BIN or 
*.BINM) DOE-2 file to a humanly -readable text  *.FMT or *.FMTM file.

E-mail me for details.

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

On 2/9/2015 12:33 PM, RobertWichert wrote:
> These weather files are great, thanks for the info, but I am trying to get wet bulb 
> temperature too, and they do not seem to give wet bulb temperatures.
>
> Any ideas on that, perhaps?
>
>
> -- 
> Robert P. Wichert P.Eng.  LEED AP
> CEPE  CEA  HERS I/II BPI BA
> +1 916 966 9060
> FAX +1 916 966 9068
>
>
> ========================================
> On 1/30/2015 9:10 PM, Joe Huang wrote:
>> White Box Technologies (WBT), in collaboration with the National Renewable Energy 
>> Laboratory (NREL), has revised the TMY3 weather files to correct inconsistencies in 
>> units for illuminances, improve the reporting of Liquid Precipitation, replace all 
>> missing records with interpolated or filled values (chiefly for visibility, ceiling 
>> height, aerosol optical depth, and albedo), and add a new variable for Present Weather.
>>
>> Since their release in 2005, the TMY3 weather files covering 1,020 locations in the US 
>> and dependencies has become the standard set of weather files for use in computer 
>> simulations of solar energy conversion systems and buildings. The intent of this 
>> revision is not to redo the fundamental analysis, but correct some known errors and 
>> make modest improvements in the reporting of subsidiary climate variables.
>>
>> The only impact from these corrections and changes are for daylighting simulations that 
>> use the illuminance values, and for building simulations that use the liquid 
>> precipitation to model green roofs or moisture transport through the building envelope. 
>> The added Present Weather variable is not directly used in any simulation program, but 
>> allows the DOE-2 BINM files to have correct IRAIN and ISNOW flags, although these two 
>> variables are not being used in DOE-2.  Filling in missing data for Visibility, Ceiling 
>> Height, etc., should have no impact on the use of the TMY3s, but improves their overall 
>> record-keeping.
>>
>> The revised TMY3 files in their native CSV format have been provided back to NREL and 
>> are available here: http://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/tmy3
>>
>> The revised TMY3 files in EPW and BINM formats are available for free download on the 
>> White Box Technologies web site at http://weather.whiteboxtechnologies.com/wd-TMY3 or 
>> by selecting File Type as "TMY3" at http:/weather.whiteboxtechnologies.com/search to 
>> search using GoogleEarth. The zip file names are unchanged, but the underlying EPW and 
>> DDY files will have the *TYA designation to distinguish them from the previous TMY3 
>> versions.
>>
>> For a more detailed description and full documentation of the revision,  please see the 
>> attached memorandum.
>>
>> Joe
>> -- 
>> Joe Huang
>> White Box Technologies, Inc.
>> 346 Rheem Blvd., Suite 205A
>> Moraga CA 94556
>> yjhuang at whiteboxtechnologies.com
>> http://weather.whiteboxtechnologies.com for simulation-ready weather data
>> (o) (925)388-0265
>> (c) (510)928-2683
>> "building energy simulations at your fingertips"
>>
>>
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