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Re: [EnergyPlus_Support] Re: New Australia weather data available for 69 locations




We've sent a note to the group that provided the data
asking about this.



                                                                                                                
                      "Paul Reeves"                                                                             
                      <paulreeves5@xxxxxxxxx>      To: EnergyPlus_Support@xxxxxxxxxxxxxxx                       
                      Sent by:                     cc:                                                          
                      EnergyPlus_Support@yaho      Subject:  [EnergyPlus_Support] Re: New Australia weather     
                      ogroups.com                     data available for 69 locations                           
                                                                                                                
                                                                                                                
                      02/09/2007 05:07 PM                                                                       
                      Please respond to                                                                         
                      EnergyPlus_Support                                                                        
                                                                                                                
                                                                                                                
                                                                                                                



It appears that there is a calculational error in some of the new
RMY data for Australia, at least with quite a few of the ones that I
reviewed. That, or Australia has some very odd cloud behavior.

It seems likely that the field direct normal solar radiation was
calculated based on a multi-pyronometer array. If the array is
symetric about the noon axis (which I guess in this case is north),
the calculation procedure that I was aware of many years ago would
break down around noon. This happened because the angle between the
sun and half of the pyronometers is equal to the angle between the
sun and the other half of the pyronometers. The end result is the
noon-hour depression that can be scene in at least these files:

Direct Solar Noon Depression with these files:
- AUS_NSW.Coffs.Harbour_RMY.epw
- AUS_QLD.Gladstone.Airport_RMY.epw
- AUS_QLD.Weipa.Aero_RMY
- AUS_WA.Forrest_RMY

No problem with these files:
- AUS_NSW.Wagga.Wagga_RMY
- AUS_ACT.Canberra.Airport_RMY

The direct normal solar takes a 20-30% "dip" around noon, when in
fact it should be peaking. When the problem exists, it happens
virtually every day (all except days that are completely overcast).

There are reliable algorithms that calculate direct normal solar
based on global horizontal and moisture content (the Perez
Corellation, as I recall). I have tested this correlation against
measured data and it appears quite robust. It is almost certainly
better than using weather data that underestimates mid-day direct
solar radiation by so much.

Paul Reeves

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Drury.Crawley@... wrote:
>
> New weather data for 69 Australian locations are
> now available on the EnergyPlus web site. The RMY
> Australia Representative Meteorological Year
> Climate Files were developed for the Australia
> Greenhouse Office for use in complying with Building
> Code of Australia.
>
>
http://www.eere.energy.gov/buildings/energyplus/cfm/weather_data3.cfm
/region=5_southwest_pacific_wmo_region_5/country=AUS/cname=Australia
>
> This brings the total number of weather files available on the
EnergyPlus
> web site to more than 1300 worldwide.
>
> As always, if you know of typical weather data sets for your
country
> or region, please let us know about them!
>
> The EnergyPlus Team
>








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