[EnergyPlus_Support] Re: Sizing according to ASHRAE 90.1

["FrancescoP" <direzionecontraria@xxxxxxxx>]

I noticed that for that station (and also for other stations) the coldest temperatures of the test reference year are lower than the design temperature:  for Milano IWEC the coldest temperature of the test reference year is -10.85°C while the heating design temperature is -9.1°C. ASHRAE Fundamentals handbook 1997 (unfortunately I don't have version 2009) states that it provides "Dry-bulb temperature corresponding to 99.6% and 99.0% annual cumulative frequency of occurrence (cold)". Therefore, are the data of the design days available in http://www.energyplus.gov/weatherdata_about.cfm relative to long-term periods or relative to the test reference years?

Best Regards

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Dru Crawley <dbcrawley@...> wrote:
>
> Weather data rarely contains the 99.6% or 1% values ... those are based on
> a long-term period.  These specifically refer to the design conditions in
> ASHRAE Handbook Fundamentals (also in ASHRAE Standard 169).
> 
> Where there are design conditions in the Handbook, a .DDY file is created
> when the weather data is processed.  .DDY fiels contain the design
> condtions in .IDF format.  These are included in the .ZIP for the weather
> files that are posted on the EnergyPlus web site (
> http://www.energyplus.gov/weatherdata_about.cfm).
> An example from the Milano IWEC .zip (the .DDY includes many more design
> conditions that can be used):
> 
>  Site:Location,
>   MILAN_ITA Design_Conditions,     !- Location Name
>       45.62,     !- Latitude {N+ S-}
>        8.73,     !- Longitude {W- E+}
>        1.00,     !- Time Zone Relative to GMT {GMT+/-}
>      211.00;     !- Elevation {m}
> 
>  !  WMO=160660 Time Zone=EUW: (GMT+01:00) Amsterdam, Berlin, Bern, Rome,
> Stockholm, Vienna
>  !  Data Source=ASHRAE 2009 Annual Design Conditions
>  RunPeriodControl:DaylightSavingTime,
>    Last Sunday in March,    !- StartDate
>    Last Sunday in October;    !- EndDate
> 
>  ! Using Design Conditions from "Climate Design Data 2009 ASHRAE Handbook"
>  ! MILAN_ITA Extreme Annual Wind Speeds, 1%=6.8m/s, 2.5%=5m/s, 5%=3.9m/s
>  ! MILAN_ITA Extreme Annual Temperatures, Max Drybulb=-12.1°C Min
> Drybulb=34°C
> 
>  ! MILAN_ITA Annual Heating Design Conditions Wind Speed=0.2m/s Wind Dir=0
>  ! Coldest Month=JAN
>  ! MILAN_ITA Annual Heating 99.6%, MaxDB=-9.1°C
>  SizingPeriod:DesignDay,
>   MILAN Ann Htg 99.6% Condns DB,     !- Name
>           1,      !- Month
>          21,      !- Day of Month
>   WinterDesignDay,!- Day Type
>        -9.1,      !- Maximum Dry-Bulb Temperature {C}
>         0.0,      !- Daily Dry-Bulb Temperature Range {C}
>  DefaultMultipliers, !- Dry-Bulb Temperature Range Modifier Type
>            ,      !- Dry-Bulb Temperature Range Modifier Schedule Name
>     Wetbulb,      !- Humidity Condition Type
>        -9.1,      !- Wetbulb at Maximum Dry-Bulb {C}
>            ,      !- Humidity Indicating Day Schedule Name
>            ,      !- Humidity Ratio at Maximum Dry-Bulb {kgWater/kgDryAir}
>            ,      !- Enthalpy at Maximum Dry-Bulb {J/kg}
>            ,      !- Daily Wet-Bulb Temperature Range {deltaC}
>      98816.,      !- Barometric Pressure {Pa}
>         0.2,      !- Wind Speed {m/s} design conditions vs. traditional
> 6.71 m/s (15 mph)
>           0,      !- Wind Direction {Degrees; N=0, S=180}
>          No,      !- Rain {Yes/No}
>          No,      !- Snow on ground {Yes/No}
>          No,      !- Daylight Savings Time Indicator
>   ASHRAEClearSky, !- Solar Model Indicator
>            ,      !- Beam Solar Day Schedule Name
>            ,      !- Diffuse Solar Day Schedule Name
>            ,      !- ASHRAE Clear Sky Optical Depth for Beam Irradiance
> (taub)
>            ,      !- ASHRAE Clear Sky Optical Depth for Diffuse Irradiance
> (taud)
>        0.00;      !- Clearness {0.0 to 1.1}
> 
> 
>  ! MILAN_ITA Annual Cooling (DB=>MWB) 1%, MaxDB=30.6°C MWB=21.9°C
>  SizingPeriod:DesignDay,
>   MILAN Ann Clg 1% Condns DB=>MWB,     !- Name
>           7,      !- Month
>          21,      !- Day of Month
>   SummerDesignDay,!- Day Type
>        30.6,      !- Maximum Dry-Bulb Temperature {C}
>          12,      !- Daily Dry-Bulb Temperature Range {C}
>  DefaultMultipliers, !- Dry-Bulb Temperature Range Modifier Type
>            ,      !- Dry-Bulb Temperature Range Modifier Schedule Name
>     Wetbulb,      !- Humidity Condition Type
>        21.9,      !- Wetbulb at Maximum Dry-Bulb {C}
>            ,      !- Humidity Indicating Day Schedule Name
>            ,      !- Humidity Ratio at Maximum Dry-Bulb {kgWater/kgDryAir}
>            ,      !- Enthalpy at Maximum Dry-Bulb {J/kg}
>            ,      !- Daily Wet-Bulb Temperature Range {deltaC}
>      98816.,      !- Barometric Pressure {Pa}
>           2,      !- Wind Speed {m/s} design conditions vs. traditional
> 3.35 m/s (7mph)
>         240,      !- Wind Direction {Degrees; N=0, S=180}
>          No,      !- Rain {Yes/No}
>          No,      !- Snow on ground {Yes/No}
>          No,      !- Daylight Savings Time Indicator
>        ASHRAETau, !- Solar Model Indicator
>            ,      !- Beam Solar Day Schedule Name
>            ,      !- Diffuse Solar Day Schedule Name
>       0.488,      !- ASHRAE Clear Sky Optical Depth for Beam Irradiance
> (taub)
>       1.889;      !- ASHRAE Clear Sky Optical Depth for Diffuse Irradiance
> (taud)
> 
> 
> 
> On Tue, Aug 21, 2012 at 11:08 AM, FrancescoP direzionecontraria@...wrote:
> 
> > **
> >
> >
> > Unfortunately, I have another doubt. What is the best solution for the
> > choice of the weather data for the sizing period? I know that I have to
> > respect paragraph G3.1.2.2.1 but I don't have statistical data to develop
> > "design days developed using 99.6% heating design temperature and 1%
> > dry-bulb and 1% wetbulb cooling design temperatures".
> > Is using the same test reference year that I use for the annual simulation
> > acceptable for LEED reviewers?
> > In that case, I would use the object "SizingPeriod:WeatherFileDays" and I
> > would create two objects: one with the three coldest months (field "Day of
> > Week for Start Day": WinterDesignDay) the other one with the three warmest
> > months (field "Day of Week for Start Day": WinterDesignDay). Do you think
> > it is a good idea?
> > Best Regards
> > Francesco
> >
> >  
> >
>

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