Simulation community -
So I'm in the proposed modeling phase of LEED energy simulation, and I'm having some problems hard sizing some cooling coils for some split dx heat pump units serving technology closets. See error below, it looks like I'm inputting what I think is the total cooling capacity, but its calculating something else for the "Design Size Gross Rated Total Cooling Capacity."
*** SizeDXCoil: Potential issue with equipment sizing for Coil:Cooling:DX:SingleSpeed DX-1 SYSTEM COOLING COIL * ~~~ * User-Specified Gross Rated Total Cooling Capacity [W] = 5274.00000 * ~~~ * differs from Design Size Gross Rated Total Cooling Capacity [W] = 3590.75955 * ~~~ * This may, or may not, indicate mismatched component sizes.
So I must be missing an input, but since I'm just using the template objects so I think its pretty straightforward: - HVACTemplate:System:UnitaryHeatPump:AirToAir - HVACTemplate:Zone:Unitary
I'm inputting a hard value for the Supply Air Maximum Flow Rate in the zone object, and I'm inputting a hard value for the "cooling supply air flow rate" and "Cooling Coil Capacity" fields in the system object. Upon checking out the coil:cooling:water object in the expanded .idf, it looks like everything is hardsized properly. Not sure what's going on here, but the slight reduction in capacity is causing unmet hours in the proposed case.
Here are the text objects in case anyone is interested:
HVACTemplate:Zone:Unitary,
DX-1, !Zone Name
DX-1 system, !Template Unitary System Name
carver_admin_tstat, !Template Thermostat Name
0.22, !Supply Air Maximum Flow Rate {m3/s}
, !Zone Heating Sizing Factor
, !Zone Cooling Sizing Factor
sum, !Outdoor Air Method
, !Outdoor Air Flow Rate per Person {m3/s}
0.0006096, !Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
, !Outdoor Air Flow Rate per Zone {m3/s}
, !Supply Plenum Name
, !Return Plenum Name
, !Baseboard Heating Type
, !Baseboard Heating Availability Schedule Name
, !Baseboard Heating Capacity {W}
TEMPERATUREDIFFERENCE, !Zone Cooling Design Supply Air Temperature Input Method
, !Zone Cooling Design Supply Air Temperature {C}
11.31, !Zone Cooling Design Supply Air Temperature Difference {deltaC}
TEMPERATUREDIFFERENCE, !Zone Heating Design Supply Air Temperature Input Method
, !Zone Heating Design Supply Air Temperature {C}
11.31; !Zone Heating Design Supply Air Temperature Difference {deltaC}
HVACTemplate:System:UnitaryHeatPump:AirToAir,
DX-1 system, !Name
admin_outside_air_schedule_compact, !System Availability Schedule Name
DX-1, !Control Zone or Thermostat Location Name
0.22, !Cooling Supply Air Flow Rate {m3/s}
0.22, !Heating Supply Air Flow Rate {m3/s}
0, !No Load Supply Air Flow Rate {m3/s}
admin_outside_air_schedule_compact, !Supply Fan Operating Mode Schedule Name
blowthrough, !Supply Fan Placement
0.7, !Supply Fan Total Efficiency
117.0829616414, !Supply Fan Delta Pressure {Pa}
0.99, !Supply Fan Motor Efficiency
1, !Supply Fan Motor in Air Stream Fraction
singlespeeddx, !Cooling Coil Type
, !Cooling Coil Availability Schedule Name
12.8, !Cooling Design Supply Air Temperature {C}
5274, !Cooling Coil Capacity {W}
autosize, !Cooling Coil Rated Sensible Heat Ratio
3.48, !Cooling Coil Rated COP
Singlespeeddxheatpump, !Heat Pump Heating Coil Type
, !Heat Pump Heating Coil Availability Schedule Name
50, !Heating Design Supply Air Temperature {C}
, !Heat Pump Heating Coil Rated Capacity {W}
2.75, !Heat Pump Heating Coil Rated COP
-8, !Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature {C}
5, !Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature {C}
Reversecycle, !Heat Pump Defrost Strategy
timed, !Heat Pump Defrost Control
0.058333, !Heat Pump Defrost Time Period Fraction
Electric, !Supplemental Heating Coil Type
, !Supplemental Heating Coil Availability Schedule Name
autosize, !Supplemental Heating Coil Capacity {W}
21, !Supplemental Heating Coil Maximum Outdoor Dry-Bulb Temperature {C}
0.8, !Supplemental Gas Heating Coil Efficiency
0, !Supplemental Gas Heating Coil Parasitic Electric Load {W}
autosize, !Maximum Outdoor Air Flow Rate {m3/s}
autosize, !Minimum Outdoor Air Flow Rate {m3/s}
admin_outside_air_schedule_compact, !Minimum Outdoor Air Schedule Name
noeconomizer, !Economizer Type
, !Economizer Lockout
, !Economizer Maximum Limit Dry-Bulb Temperature {C}
, !Economizer Maximum Limit Enthalpy {J/kg}
, !Economizer Maximum Limit Dewpoint Temperature {C}
, !Economizer Minimum Limit Dry-Bulb Temperature {C}
, !Supply Plenum Name
, !Return Plenum Name
cycleonany, !Night Cycle Control
DX-1, !Night Cycle Control Zone Name
, !Heat Recovery Type
, !Sensible Heat Recovery Effectiveness
, !Latent Heat Recovery Effectiveness
, !Humidifier Type
, !Humidifier Availability Schedule Name
, !Humidifier Rated Capacity {m3/s}
, !Humidifier Rated Electric Power
, !Humidifier Control Zone Name
; !Humidifier Setpoint {%}
Expanded Coil Object from .idfexp
Coil:Cooling:DX:SingleSpeed,
DX-1 system Cooling Coil, !- Name
HVACTemplate-Always 1, !- Availability Schedule Name
5274, !- Gross Rated Total Cooling Capacity {W}
autosize, !- Gross Rated Sensible Heat Ratio
3.48, !- Rated COP
0.22, !- Rated Air Flow Rate {m3/s}
, !- Rated Evaporator Fan Power per Volume Flow Rate {W/(m3/s)}
DX-1 system Supply Fan Outlet, !- Air Inlet Node Name
DX-1 system Cooling Coil Outlet, !- Air Outlet Node Name
DX-1 system Cool Coil Cap-FT, !- Total Cooling Capacity Function of Temperature Curve Name
DX-1 system Cool Coil Cap-FF, !- Total Cooling Capacity Function of Flow Fraction Curve Name
DX-1 system Cool Coil EIR-FT, !- Energy Input Ratio Function of Temperature Curve Name
DX-1 system Cool Coil EIR-FF, !- Energy Input Ratio Function of Flow Fraction Curve Name
DX-1 system Cool Coil PLF, !- Part Load Fraction Correlation Curve Name
0, !- Nominal Time for Condensate Removal to Begin
0, !- Ratio of Initial Moisture Evaporation Rate and Steady State Latent Capacity
0, !- Maximum Cycling Rate
0, !- Latent Capacity Time Constant
DX-1 system Cooling Coil Condenser Inlet, !- Condenser Air Inlet Node Name
AirCooled, !- Condenser Type
0, !- Evaporative Condenser Effectiveness
, !- Evaporative Condenser Air Flow Rate
0, !- Evaporative Condenser Pump Rated Power Consumption
0, !- Crankcase Heater Capacity
10; !- Maximum Outdoor Dry-Bulb Temperature for Crankcase Heater Operation
