[Bldg-sim] climate zone Rome

[Joe Huang]

Following up on this question ("Why is Rome in ASHRAE Climate Zone 4 when the weather 
files say it has less 1514 HDD ?),
I checked through various versions of ASHRAE 90.1 and Standard 169. Rome was so listed as 
CZ 4 in Version 2004 (which I have) down through Version 2010 (which I don't have but 
trusting what Francesco said :-)), but as CZ 3A in Version 2013.

However, when I looked in the Table D-3 of Version 2004, it gives Rome as having 2684 
HDD65 (Fahrenheit), which converts to 1491 HDD10 (Celsius), which is consistent with the 
1541 HDD10 of the weather file that Francesco is using  (there are always a few percentage 
point differences between the long-term HDD and that from a typical year file).

Therefore, my conclusion is that there's a mistake in ASHRAE 90.1-2010, and my suggestion 
to Francesco is to base the reference building thermal properties on Climate Zone 3A for 
ASHRAE 90.1-2013, or if you don't have a copy, use Climate Zone 3A for ASHRAE 90.1-2010 
and point out the error to whoever judges your LEED application.  It should be a "no-brainer".

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 2/3/2016 7:42 AM, Joe Huang wrote:
> I beg to differ on this.  ASHRAE Climate Zones are very simply defined based of degree 
> days, plus what I consider a  faulty use of precipitation to differentiate "wet" from 
> "dry" climates.  When a EPW stat file gives the ASHRAE Climate Zone as 3, it's simply 
> reporting the number of degree days in the file, and in that sense, absolutely correct.  
> The reason for the discrepancy is that ASHRAE 90.1, or actually ASHRAE Standard 169 
> (Climate Data for Building Design Standards), did their climate zone mapping, they came 
> up with a degree day value that put Rome in Climate Zone 4. The problem in this case is 
> that all 3 weather files for Rome that I've looked into (IWEC, IWEC2, IGDG - the one  
> used by Francesco) show HDD from 1440 to 1514, much below the 2000 HDD to fall into 
> Climate Zone 4. I have a good idea how Standard 169 derived its degree days, but am 
> waiting for confirmation lest I misspeak.
>
> In the meanwhile, I would also recommend using the climate zone shown in 90.1 to set the 
> reference building, but only because that's what listed, not because it's technically 
> better.
>
> 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 2/3/2016 6:43 AM, Jim Dirkes wrote:
>> Francesco,
>> As I recall, the E+ weather files derive the climate zone based on various attributes 
>> of the weather data.  In fact, I think there is a qualifying statement within the .EPW 
>> files which says the climate zone may not be "perfect"
>> For that reason, I would use the climate zone referenced in 90.1
>>
>> On Wed, Feb 3, 2016 at 9:15 AM, Francesco Passerini <fpasserini.tn at gmail.com> wrote:
>>
>>     In order to understand what thermal transmittances I shall impose in a baseline
>>     model for LEED, I have to understand in what climate zone I shall consider Rome.
>>     In TABLE B-3 "International Climate Zones" of ASHRAE 90.1-2010, "Roma/Fiumicion" is
>>     zone 4, while in the weather file zone 3C is indicated.
>>     The weather file for Fiumicino is available here:
>>     https://energyplus.net/weather-location/europe_wmo_region_6/ITA//ITA_Roma-Fiumicino.162420_IGDG
>>     If you see the .stat file, HDD18°C = 1514, which respects the thermal criteria for
>>     zone 3C (see Table B-4).
>>     Is TABLE B-3 based on other weather data?
>>     Best Regards
>>     Francesco
>>
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>>
>>
>>
>> -- 
>>
>> James V Dirkes II, PE, BEMP, LEED AP
>> CEO/President
>> The Building Performance Team Inc.
>> 1631 Acacia Dr, GR, Mi 49504
>>
>> Direct: 616.450.8653
>> jim at buildingperformanceteam.com
>>
>> Website <http://buildingperformanceteamcom>l LinkedIn 
>> <https://www.linkedin.com/pub/jim-dirkes/7/444/413>
>>
>> *//*
>>
>> Fail faster!
>>
>>
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