Hi Karen
Perhaps your AHU starts before your CHW plant? I've seen this error pop up in that case. I suggest getting outputs at the timestep level and then checking if this occurs at the timestep the error is reported.
Regards,
Benson
Sent: Tuesday, 12 July 2016 3:35 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] FindRootSimpleController Sever errors
** ~~~ ** Controller sensed temperature = 16.65 [C], considerably higher than the 12.4C setpoint? Is your chiller and pump working?
One of idf model I am working is showing me the Controller error as bellow for all the VAV Cooling coil controller
** Severe ** FindRootSimpleController: Controller error for controller = "VAV_1_COOLC_CONTROLLER"
** ~~~ ** Environment=ANNUAL, at Simulation time=01/27 18:40 - 18:50
** ~~~ ** Controller function is inconsistent with user specified controller action = "" action
** ~~~ ** Actuator will be set to maximum action
** ~~~ ** Controller control type=Temperature
** ~~~ ** Controller temperature setpoint = 12.40 [C]
** ~~~ ** Controller sensed temperature = 16.65 [C]
** ~~~ ** Controller actuator mass flow rate set to 10.87 [kg/s]
** ~~~ ** Controller actuator temperature = 16.67 [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
I have set the ChilledWater coils to reverse action and my Controller is using setpointmanager as
SetpointManager:MixedAir,
VAV_1_CoolC SAT Manager, !- Name
Temperature, !- Control Variable
VAV_1 Supply Equipment Outlet Node, !- Reference Setpoint Node Name
VAV_1_HeatC-VAV_1_FanNode, !- Fan Inlet Node Name
VAV_1 Supply Equipment Outlet Node, !- Fan Outlet Node Name
VAV_1_CoolC-VAV_1_HeatCNode; !- Setpoint Node or NodeList Name
************* ** Severe ** FindRootSimpleController: Previous controller action error continues for controller = VAV_1_COOLC_CONTROLLER
************* ** ~~~ ** This error occurred 11 total times;
************* ** ~~~ ** during Warmup 0 times;
************* ** ~~~ ** during Sizing 0 times.
I get 48 of these warnings with year of simulation. Can this be ignored safely considering only 12 times in a year for each controller.
James V Dirkes II, PE, BEMP, LEED AP
CEO/President
The Building Performance Team Inc.
1631 Acacia Dr, GR, Mi 49504
Direct: 616.450.8653
jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx
Website l LinkedIn | May 2016 ASHRAE Journal article on energy modeling
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Posted by: Benson Coelho <ben_coelho@xxxxxxxxxxx>
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