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Re: [EnergyPlus_Support] Re: Sizing according to ASHRAE 90.1
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@xxxxxxxx> 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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