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[EnergyPlus_Support] Severe errors for Fan Power modelling of VAV system
Dear all:
In a baseline building modeling for LEED EApr2 documentation, I have some troubles with the simulation reports that shows unusually high amounts of severe errors (over 1000); when I try to model System Fan Power according ASHRAE 90.1-2007, G3.1.2.9.
I am concerned if we can be observed by LEED reviewer team about this severe warnings.
Simulation details:
-Baseline model consist of six-levels building for typical office usage (8000m2 area approx.)
-HVAC system type 8, VAV with PFP zones according ASHRAE 90.1-2007 appendix G.
-Energyplus 6.0.0.023 software has been used.
-HVAC systems has been modeled with HVAC templates in this configuration:
-Chilled Water loop with HVACTemplate:Plant:ChilledWaterLoop, Chiller and Cooling Tower
-System-side equipment with HVACTemplate:System:VAV
-Zone-side equipment with HVACTemplate:Zone:VAV:FanPowered
-System Fan Power modeling details:
-Supply Fan Total Efficiency = 0.6
-Supply Fan Delta Pressure = 1495 Pa
-Supply Fan Motor Efficiency = 0.9
-Severe errors details:
When Supply Fan Delta Pressure exceeds 500Pa, simulation error log exposes unusually high amounts of recurrent severe errors like that (over 1000 severe errors):
** Severe ** FindRootSimpleController: Controller error for controller = SYSTEMVAV_DATACENTER COOLING COIL CONTROLLER
** ~~~ ** Environment=SANTIAGO, at Simulation time=01/01 04:30 - 04:35
** ~~~ ** Controller function is inconsistent with user specified controller action = Reverse action
** ~~~ ** Actuator will be set to maximum action
** ~~~ ** Controller control type=Temperature
** ~~~ ** Controller temperature set point = 11.41 [C]
** ~~~ ** Controller sensed temperature = 12.17 [C]
** ~~~ ** Controller actuator mass flow rate set to 0.70 [kg/s]
** ~~~ ** Controller actuator temperature = 12.20 [C]
** ~~~ ** Note: Chilled water coils should be reverse action and the entering chilled
** ~~~ ** water temperature (controller actuator temperature) should be below the setpoint temperature
** ~~~ ** Note: Hot water coils should be normal action and the entering hot
** ~~~ ** water temperature (controller actuator temperature) should be above the setpoint temperature
Also I tried to reduce Supply Fan Total Efficiency and maintain Supply Fan Delta Pressure less than 500Pa but severe errors also occurred.
Suggestions to reduce this errors or modeling system fan power in a different way?
Any comments will be appreciated....
Regards
Alvaro Urrutia Astorga
Arquitecto.
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