Re: [EnergyPlus_Support] Re: Sizing according to ASHRAE 90.1

On Thu, Aug 23, 2012 at 4:30 AM, FrancescoP <direzionecontraria@xxxxxxxx> wrote:

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
> >
> >
> >
>