My model is the same as this post, but let me post a different question.
I have a problem with Coincident plant sizing for CondenserLoop. I tried both Coincident sizing and NonCoincident sizing, but the weird thing is that the autosized condenser loop (Cooling towers and condenser water pumps) by Coincident sizing is much larger than that by NonCoincident sizing. It does not happen in PlantLoop (chillers and chilled water pumps). I think my Coincident sizing settings are appropriate.
Below are the sizing results of cooling towers. Autosized condenser water flow rate by Coincndent sizing is 0.164097m3/s, which is more than 2 times larger than the autosized condenser water flow rate of 0.072678m3/s by NonCoincident sizing. Does anyone know why?
My settings related to Coincident sizing are as follows.
SimulationControl,
Yes, !- Do Zone Sizing Calculation
Yes, !- Do System Sizing Calculation
Yes, !- Do Plant Sizing Calculation
Yes, !- Run Simulation for Sizing Periods
No, !- Run Simulation for Weather File Run Periods
Yes, !- Do HVAC Sizing Simulation for Sizing Periods
1; !- Maximum Number of HVAC Sizing Simulation Passes
Sizing:Parameters,
1.25, !- Heating Sizing Factor
1.15; !- Cooling Sizing Factor
Sizing:System,
VAV_3, !- AirLoop Name
Sensible, !- Type of Load to Size On
autosize, !- Design Outdoor Air Flow Rate {m3/s}
autosize, !- Central Heating Maximum System Air Flow Ratio
30, !- Preheat Design Temperature {C}
0.0033, !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
11, !- Precool Design Temperature {C}
0.008, !- Precool Design Humidity Ratio {kgWater/kgDryAir}
15, !- Central Cooling Design Supply Air Temperature {C}
22, !- Central Heating Design Supply Air Temperature {C}
Coincident, !- Type of Zone Sum to Use
No, !- 100% Outdoor Air in Cooling
No, !- 100% Outdoor Air in Heating
0.008, !- Central Cooling Design Supply Air Humidity Ratio {kgWater/kgDryAir}
0.008, !- Central Heating Design Supply Air Humidity Ratio {kgWater/kgDryAir}
DesignDay, !- Cooling Supply Air Flow Rate Method
0, !- Cooling Supply Air Flow Rate {m3/s}
, !- Cooling Supply Air Flow Rate Per Floor Area {m3/s-m2}
, !- Cooling Fraction of Autosized Cooling Supply Air Flow Rate
, !- Cooling Supply Air Flow Rate Per Unit Cooling Capacity {m3/s-W}
DesignDay, !- Heating Supply Air Flow Rate Method
0, !- Heating Supply Air Flow Rate {m3/s}
, !- Heating Supply Air Flow Rate Per Floor Area {m3/s-m2}
, !- Heating Fraction of Autosized Heating Supply Air Flow Rate
, !- Heating Fraction of Autosized Cooling Supply Air Flow Rate
, !- Heating Supply Air Flow Rate Per Unit Heating Capacity {m3/s-W}
ZoneSum, !- 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
Sizing:System,
VAV_2, !- AirLoop Name
Sensible, !- Type of Load to Size On
autosize, !- Design Outdoor Air Flow Rate {m3/s}
autosize, !- Central Heating Maximum System Air Flow Ratio
30, !- Preheat Design Temperature {C}
0.0033, !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
11, !- Precool Design Temperature {C}
0.008, !- Precool Design Humidity Ratio {kgWater/kgDryAir}
15, !- Central Cooling Design Supply Air Temperature {C}
22, !- Central Heating Design Supply Air Temperature {C}
Coincident, !- Type of Zone Sum to Use
No, !- 100% Outdoor Air in Cooling
No, !- 100% Outdoor Air in Heating
0.008, !- Central Cooling Design Supply Air Humidity Ratio {kgWater/kgDryAir}
0.008, !- Central Heating Design Supply Air Humidity Ratio {kgWater/kgDryAir}
DesignDay, !- Cooling Supply Air Flow Rate Method
0, !- Cooling Supply Air Flow Rate {m3/s}
, !- Cooling Supply Air Flow Rate Per Floor Area {m3/s-m2}
, !- Cooling Fraction of Autosized Cooling Supply Air Flow Rate
, !- Cooling Supply Air Flow Rate Per Unit Cooling Capacity {m3/s-W}
DesignDay, !- Heating Supply Air Flow Rate Method
0, !- Heating Supply Air Flow Rate {m3/s}
, !- Heating Supply Air Flow Rate Per Floor Area {m3/s-m2}
, !- Heating Fraction of Autosized Heating Supply Air Flow Rate
, !- Heating Fraction of Autosized Cooling Supply Air Flow Rate
, !- Heating Supply Air Flow Rate Per Unit Heating Capacity {m3/s-W}
ZoneSum, !- 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
Sizing:System,
VAV_1, !- AirLoop Name
Sensible, !- Type of Load to Size On
autosize, !- Design Outdoor Air Flow Rate {m3/s}
autosize, !- Central Heating Maximum System Air Flow Ratio
30, !- Preheat Design Temperature {C}
0.0033, !- Preheat Design Humidity Ratio {kgWater/kgDryAir}
11, !- Precool Design Temperature {C}
0.008, !- Precool Design Humidity Ratio {kgWater/kgDryAir}
15, !- Central Cooling Design Supply Air Temperature {C}
22, !- Central Heating Design Supply Air Temperature {C}
Coincident, !- Type of Zone Sum to Use
No, !- 100% Outdoor Air in Cooling
No, !- 100% Outdoor Air in Heating
0.008, !- Central Cooling Design Supply Air Humidity Ratio {kgWater/kgDryAir}
0.008, !- Central Heating Design Supply Air Humidity Ratio {kgWater/kgDryAir}
DesignDay, !- Cooling Supply Air Flow Rate Method
0, !- Cooling Supply Air Flow Rate {m3/s}
, !- Cooling Supply Air Flow Rate Per Floor Area {m3/s-m2}
, !- Cooling Fraction of Autosized Cooling Supply Air Flow Rate
, !- Cooling Supply Air Flow Rate Per Unit Cooling Capacity {m3/s-W}
DesignDay, !- Heating Supply Air Flow Rate Method
0, !- Heating Supply Air Flow Rate {m3/s}
, !- Heating Supply Air Flow Rate Per Floor Area {m3/s-m2}
, !- Heating Fraction of Autosized Heating Supply Air Flow Rate
, !- Heating Fraction of Autosized Cooling Supply Air Flow Rate
, !- Heating Supply Air Flow Rate Per Unit Heating Capacity {m3/s-W}
ZoneSum, !- 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
Sizing:Plant,
CHWloop Chilled Water Loop, !- Plant or Condenser Loop Name
Cooling, !- Loop Type
6.7, !- Design Loop Exit Temperature {C}
6.3, !- Loop Design Temperature Difference {deltaC}
Coincident, !- Sizing Option
, !- Zone Timesteps in Averaging Window
None; !- Coincident Sizing Factor Mode
Sizing:Plant,
CHWloop Condenser Water Loop, !- Plant or Condenser Loop Name
Condenser, !- Loop Type
29, !- Design Loop Exit Temperature {C}
5.6, !- Loop Design Temperature Difference {deltaC}
Coincident, !- Sizing Option
, !- Zone Timesteps in Averaging Window
None; !- Coincident Sizing Factor Mode
CoolingTower:TwoSpeed,
coolingtower1, !- Name
coolingtower1 CndW Inlet,!- Water Inlet Node Name
coolingtower1 CndW Outlet, !- Water Outlet Node Name
autosize, !- Design Water Flow Rate {m3/s}
autosize, !- High Fan Speed Air Flow Rate {m3/s}
autosize, !- High Fan Speed Fan Power {W}
autosize, !- High Fan Speed U-Factor Times Area Value {W/K}
autocalculate, !- Low Fan Speed Air Flow Rate {m3/s}
, !- Low Fan Speed Air Flow Rate Sizing Factor
autocalculate, !- Low Fan Speed Fan Power {W}
, !- Low Fan Speed Fan Power Sizing Factor
autocalculate, !- Low Fan Speed U-Factor Times Area Value {W/K}
, !- Low Fan Speed U-Factor Times Area Sizing Factor
autocalculate, !- Free Convection Regime Air Flow Rate {m3/s}
, !- Free Convection Regime Air Flow Rate Sizing Factor
autocalculate, !- Free Convection Regime U-Factor Times Area Value {W/K}
, !- Free Convection U-Factor Times Area Value Sizing Factor
UFactorTimesAreaAndDesignWaterFlowRate, !- Performance Input Method
, !- Heat Rejection Capacity and Nominal Capacity Sizing Ratio
, !- High Speed Nominal Capacity {W}
autocalculate, !- Low Speed Nominal Capacity {W}
, !- Low Speed Nominal Capacity Sizing Factor
autocalculate, !- Free Convection Nominal Capacity {W}
, !- Free Convection Nominal Capacity Sizing Factor
, !- Design Inlet Air Dry-Bulb Temperature {C}
, !- Design Inlet Air Wet-Bulb Temperature {C}
, !- Design Approach Temperature {deltaC}
, !- Design Range Temperature {deltaC}
, !- Basin Heater Capacity {W/K}
, !- Basin Heater Setpoint Temperature {C}
, !- Basin Heater Operating Schedule Name
SaturatedExit, !- Evaporation Loss Mode
, !- Evaporation Loss Factor {percent/K}
0.008, !- Drift Loss Percent {percent}
ConcentrationRatio, !- Blowdown Calculation Mode
3, !- Blowdown Concentration Ratio
, !- Blowdown Makeup Water Usage Schedule Name
, !- Supply Water Storage Tank Name
coolingtower1 Cooling Tower Outdoor Air Inlet Node, !- Outdoor Air Inlet Node Name
, !- Number of Cells
, !- Cell Control
, !- Cell Minimum Water Flow Rate Fraction
, !- Cell Maximum Water Flow Rate Fraction
0.5; !- Sizing Factor
CoolingTower:TwoSpeed,
coolingtower2, !- Name
coolingtower2 CndW Inlet,!- Water Inlet Node Name
coolingtower2 CndW Outlet, !- Water Outlet Node Name
autosize, !- Design Water Flow Rate {m3/s}
autosize, !- High Fan Speed Air Flow Rate {m3/s}
autosize, !- High Fan Speed Fan Power {W}
autosize, !- High Fan Speed U-Factor Times Area Value {W/K}
autocalculate, !- Low Fan Speed Air Flow Rate {m3/s}
, !- Low Fan Speed Air Flow Rate Sizing Factor
autocalculate, !- Low Fan Speed Fan Power {W}
, !- Low Fan Speed Fan Power Sizing Factor
autocalculate, !- Low Fan Speed U-Factor Times Area Value {W/K}
, !- Low Fan Speed U-Factor Times Area Sizing Factor
autocalculate, !- Free Convection Regime Air Flow Rate {m3/s}
, !- Free Convection Regime Air Flow Rate Sizing Factor
autocalculate, !- Free Convection Regime U-Factor Times Area Value {W/K}
, !- Free Convection U-Factor Times Area Value Sizing Factor
UFactorTimesAreaAndDesignWaterFlowRate, !- Performance Input Method
, !- Heat Rejection Capacity and Nominal Capacity Sizing Ratio
, !- High Speed Nominal Capacity {W}
autocalculate, !- Low Speed Nominal Capacity {W}
, !- Low Speed Nominal Capacity Sizing Factor
autocalculate, !- Free Convection Nominal Capacity {W}
, !- Free Convection Nominal Capacity Sizing Factor
, !- Design Inlet Air Dry-Bulb Temperature {C}
, !- Design Inlet Air Wet-Bulb Temperature {C}
, !- Design Approach Temperature {deltaC}
, !- Design Range Temperature {deltaC}
, !- Basin Heater Capacity {W/K}
, !- Basin Heater Setpoint Temperature {C}
, !- Basin Heater Operating Schedule Name
SaturatedExit, !- Evaporation Loss Mode
, !- Evaporation Loss Factor {percent/K}
0.008, !- Drift Loss Percent {percent}
ConcentrationRatio, !- Blowdown Calculation Mode
3, !- Blowdown Concentration Ratio
, !- Blowdown Makeup Water Usage Schedule Name
, !- Supply Water Storage Tank Name
coolingtower2 Cooling Tower Outdoor Air Inlet Node, !- Outdoor Air Inlet Node Name
, !- Number of Cells
, !- Cell Control
, !- Cell Minimum Water Flow Rate Fraction
, !- Cell Maximum Water Flow Rate Fraction
0.5; !- Sizing Factor
