Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I'm getting a different answer than yours in V8.6. Not sure if I am doing something wrong or if something changed between V8.5 and V8.6. I did pull your weather file so that's not it.
For the Lab Gas Heating Coil I get:
DesVolFlow = 3.27593 m3/s
DesMassFlow = 3.30242 kg/s
CoilInletTemp = -14.5 C
CoilOutletTemp = 13.88888 C
CpAirStd = 1004.8586
CoilLoad = CpAirStd * DesMassFlow * ( CoilOutletTemp - CoilInletTemp )
CoilLoad = 94207.4 Watts
From the eio:
Component Sizing Information, Coil:Heating:Fuel, LAB GAS HEATING COIL, Design Size Nominal Capacity [W], 94207.40944
Component Sizing Information, Fan:VariableVolume, LAB VARIABLE VOLUME SUPPLY FAN, Design Size Maximum Flow Rate [m3/s], 10.91976
So the question is why the flow is reported as 10.9 m3/s when sizing is using 3.3 m3/s?
It might be because the terminal units use a 0.3 fraction for minimum air flow.
AirTerminal:SingleDuct:VAV:Reheat,
0.3, !- Constant Minimum Air Flow Fraction
| | 2 | No.2 Revision |
I'm getting a different answer than yours in V8.6. Not sure if I am doing something wrong or if something changed between V8.5 and V8.6. I did pull your weather file so that's not it.
For the Lab Gas Heating Coil I get:
DesVolFlow = 3.27593 m3/s
DesMassFlow = 3.30242 kg/s
CoilInletTemp = -14.5 C
CoilOutletTemp = 13.88888 C
CpAirStd = 1004.8586
CoilLoad = CpAirStd * DesMassFlow * ( CoilOutletTemp - CoilInletTemp )
CoilLoad = 94207.4 Watts
From the eio:
Component Sizing Information, Coil:Heating:Fuel, LAB GAS HEATING COIL, Design Size Nominal Capacity [W], 94207.40944
Component Sizing Information, Fan:VariableVolume, LAB VARIABLE VOLUME SUPPLY FAN, Design Size Maximum Flow Rate [m3/s], 10.91976
So the question is why the flow is reported as 10.9 m3/s when sizing is using 3.3 m3/s?
It might be because the terminal units use a 0.3 fraction for minimum air flow.flow and the heating coil mistakenly uses this value.
AirTerminal:SingleDuct:VAV:Reheat,
0.3, !- Constant Minimum Air Flow Fraction
