Hello,
I am using CBECC-Com for Title 24, though I think this is an E+ (v8.1) error. The actual error is:
* Severe * Bad starting values for UA
UA
* Fatal * Autosizing of cooling tower UA failed for tower COOLING TOWER
From what I can tell all the plant sizing and cooling tower inputs are there and reasonable, but I'm not even sure where to look, as there is only one instance of this error I can find online and adjusting the loop temperatures didn't seem to affect it.
I'd appreciate any thought on where to look for the cause. I did find in the code that it is in response to a "-2" error code from the solver, but I can't find what triggers that.
For reference, here are my CT and sizing objects
CoolingTower:SingleSpeed,
Cooling Tower, !- Name
CW Pump Outlet Node, !- Water Inlet Node Name
Cooling Tower Outlet Node, !- Water Outlet Node Name
, !- Design Water Flow Rate {m3/s}
29.454239930112, !- Design Air Flow Rate {m3/s}
11185.5, !- Design Fan Power {W}
, !- Design U-Factor Times Area Value {W/K}
Autosize, !- Free Convection Air Flow Rate {m3/s}
0.1, !- Free Convection Air Flow Rate Sizing Factor
0, !- Free Convection U-Factor Times Area Value {W/K}
0.1, !- Free Convection U-Factor Times Area Value Sizing Factor
NominalCapacity, !- Performance Input Method
1.25, !- Heat Rejection Capacity and Nominal Capacity Sizing Ratio
3011305.24601958, !- Nominal Capacity {W}
0, !- Free Convection Capacity {W}
0.1, !- Free Convection Nominal Capacity Sizing Factor
0, !- Basin Heater Capacity {W/K}
2, !- Basin Heater Setpoint Temperature {C}
, !- Basin Heater Operating Schedule Name
, !- Evaporation Loss Mode
0.2, !- Evaporation Loss Factor {percent/K}
0.008, !- Drift Loss Percent {percent}
, !- Blowdown Calculation Mode
3, !- Blowdown Concentration Ratio
, !- Blowdown Makeup Water Usage Schedule Name
, !- Supply Water Storage Tank Name
, !- Outdoor Air Inlet Node Name
FanCycling, !- Capacity Control
2, !- Number of Cells
MinimalCell, !- Cell Control
0.33, !- Cell Minimum Water Flow Rate Fraction
2.5, !- Cell Maximum Water Flow Rate Fraction
1; !- Sizing Factor
Sizing:Plant,
Condensor Water Loop, !- Plant or Condenser Loop Name
Condenser, !- Loop Type
26.1111111111111, !- Design Loop Exit Temperature {C}
5.55555555555556; !- Loop Design Temperature Difference {deltaC}
Thanks,
Ben
