Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The ddy file contains information for the building Site:Location. The SizingPeriod:DesignDay object(s) is used when a sizing simulation is performed to automatically size equipment. The SimulationControl object specifies which parts of a sizing run will be executed. A zone sizing simulation is typically performed for any sizing simulation. A system (air loop) sizing simulation is performed when AirloopHVAC objects are included and a plant sizing simulation is performed when chllled or hot water loop are included.
SimulationControl,
Yes, !- Do Zone Sizing Calculation
Yes, !- Do System Sizing Calculation
No, !- Do Plant Sizing Calculation
Yes, !- Run Simulation for Sizing Periods
Yes; !- Run Simulation for Weather File Run Periods
When Run Simulation for Sizing Periods is set to Yes, several methods can be used to perform a sizing simulation. The most common is to use one or more SizingPeriod:DesignDay to define the most extreme weather conditions for the geographic location selected for study. Typically two or more sizing periods are selected to define the heating and cooling extreme weather conditions. The examples below show a sizing period where the conditions (temperature and moisture) specified in the SizingPeriod:DesignDay object represent 99.6% or 99% of the weather conditions for the heating season and similarly for the cooling season (i.e., an AC system would be capable of meeting the loads 99.6% or 99% of the time). You would typically select one of these for heating and one for cooling.
SizingPeriod:DesignDay,
San Francisco Intl Ap Ann Htg 99.6% Condns DB, !- Name
SizingPeriod:DesignDay,
San Francisco Intl Ap Ann Htg 99% Condns DB, !- Name
SizingPeriod:DesignDay,
San Francisco Intl Ap Ann Clg .4% Condns DB=>MWB, !- Name
SizingPeriod:DesignDay,
San Francisco Intl Ap Ann Clg 1% Condns DB=>MWB, !- Name
The systems specified to condition the building must be sized sufficiently to meet the building load (i.e., be able to meet the thermostat set points given the expected weather conditions). These systems, and other components (coils, fans, pumps, etc.) can either be manually sized by entering a value, or can be automatically sized by entering "autosize" in the field for air flow rate, capacity, water flow rate, etc.
AirTerminal:SingleDuct:VAV:Reheat,
SPACE1-1 VAV Reheat, !- Name
ReheatCoilAvailSched, !- Availability Schedule Name
SPACE1-1 Zone Coil Air In Node, !- Damper Air Outlet Node Name
SPACE1-1 ATU In Node, !- Air Inlet Node Name
autosize, !- Maximum Air Flow Rate {m3/s}
Coil:Heating:Gas,
SPACE1-1 Zone Coil, !- Name
ReheatCoilAvailSched, !- Availability Schedule Name
0.8, !- Gas Burner Efficiency
autosize, !- Nominal Capacity {W}
Fan:VariableVolume,
Supply Fan 1, !- Name
FanAvailSched, !- Availability Schedule Name
0.7, !- Fan Total Efficiency
600.0, !- Pressure Rise {Pa}
autosize, !- Maximum Flow Rate {m3/s}
AirLoopHVAC,
VAV Sys 1, !- Name
, !- Controller List Name
VAV Sys 1 Avail List, !- Availability Manager List Name
autosize, !- Design Supply Air Flow Rate {m3/s}
When autosizing equipment, in addition to using the SizingPeriod:DesignDay object(s), you will need to include sizing objects for each zone and each air loop (if included in the simulation).
Sizing:Zone,
SPACE1-1, !- Zone or ZoneList Name
SupplyAirTemperature, !- Zone Cooling Design Supply Air Temperature Input Method
16., !- Zone Cooling Design Supply Air Temperature {C}
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC}
SupplyAirTemperature, !- Zone Heating Design Supply Air Temperature Input Method
50., !- Zone Heating Design Supply Air Temperature {C}
, !- Zone Heating Design Supply Air Temperature Difference {deltaC}
0.009, !- Zone Cooling Design Supply Air Humidity Ratio {kgWater/kgDryAir}
0.004, !- Zone Heating Design Supply Air Humidity Ratio {kgWater/kgDryAir}
SZ DSOA SPACE1-1, !- Design Specification Outdoor Air Object Name
0.0, !- Zone Heating Sizing Factor
0.0, !- Zone Cooling Sizing Factor
DesignDay, !- Cooling Design Air Flow Method
0, !- Cooling Design Air Flow Rate {m3/s}
, !- Cooling Minimum Air Flow per Zone Floor Area {m3/s-m2}
, !- Cooling Minimum Air Flow {m3/s}
, !- Cooling Minimum Air Flow Fraction
DesignDay, !- Heating Design Air Flow Method
0, !- Heating Design Air Flow Rate {m3/s}
, !- Heating Maximum Air Flow per Zone Floor Area {m3/s-m2}
, !- Heating Maximum Air Flow {m3/s}
; !- Heating Maximum Air Flow Fraction
Sizing:System,
VAV Sys 1, !- AirLoop Name
sensible, !- Type of Load to Size On
autosize, !- Design Outdoor Air Flow Rate {m3/s}
0.3, !- Central Heating Maximum System Air Flow Ratio
7.0, !- Preheat Design Temperature {C}
0.008, !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
11.0, !- Precool Design Temperature {C}
0.008, !- Precool Design Humidity Ratio {kgWater/kgDryAir}
16., !- Central Cooling Design Supply Air Temperature {C}
18., !- Central Heating Design Supply Air Temperature {C}
noncoincident, !- Type of Zone Sum to Use
no, !- 100% Outdoor Air in Cooling
no, !- 100% Outdoor Air in Heating
0.009, !- Central Cooling Design Supply Air Humidity Ratio {kgWater/kgDryAir}
0.009, !- Central Heating Design Supply Air Humidity Ratio {kgWater/kgDryAir}
DesignDay, !- Cooling Design Air Flow Method
0, !- Cooling Design Air Flow Rate {m3/s}
, !- Supply Air Flow Rate Per Floor Area During Cooling Operation {m3/s-m2}
, !- Fraction of Autosized Design Cooling Supply Air Flow Rate
, !- Design Supply Air Flow Rate Per Unit Cooling Capacity {m3/s-W}
DesignDay, !- Heating Design Air Flow Method
0, !- Heating Design Air Flow Rate {m3/s}
, !- Supply Air Flow Rate Per Floor Area During Heating Operation {m3/s-m2}
, !- Fraction of Autosized Design Heating Supply Air Flow Rate
, !- Fraction of Autosized Design Cooling Supply Air Flow Rate
, !- Design Supply Air Flow Rate Per Unit Heating Capacity {m3/s-W}
, !- System Outdoor Air Method
1.0, !- Zone Maximum Outdoor Air Fraction {dimensionless}
CoolingDesignCapacity, !- Cooling Design Capacity Method
autosize, !- Cooling Design Capacity {W}
, !- Cooling Design Capacity Per Floor Area {W/m2}
, !- Fraction of Autosized Cooling Design Capacity
HeatingDesignCapacity, !- Heating Design Capacity Method
autosize, !- Heating Design Capacity {W}
, !- Heating Design Capacity Per Floor Area {W/m2}
, !- Fraction of Autosized Heating Design Capacity
VAV; !- Central Cooling Capacity Control Method
