Re: [EnergyPlus_Support] ** Severe ** FindRootSimpleController: Root finder failed at RUNPERIOD, 16:00:0

Thanks a lot Jean for you reply. But, in my idf file the maximum flow rates is always autosized. I really didn't understand about setpointmanager:singlezone:heat . I tried to debug that in code. In my input file for the coil:heating:water objects I specified the flow rates. The same flow rates I tried with the controller:watercoil objects but it still gives me the same error

From: "jeannieboef@xxxxxxxxx" <jeannieboef@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Cc: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Friday, July 12, 2013 12:55 AM
Subject: Re: [EnergyPlus_Support] ** Severe ** FindRootSimpleController: Root finder failed at RUNPERIOD, 16:00:0

Look to the minimum and maximum flowrate fields in both the controller:coil and coil:water objects.

If you put a setpoint on the control node that varies like setpointmanager:singlezone:heat which varies linearly between two bounds, like 13 to 33 deg C, then the controller may see that it must try and reach say 33 deg C, but it can't because the chilled water temp is 7 deg C. The action is reverse for cooling coil so it closes more and more to achieve a higher air temp out. The opposite also applies to the heating coil, which will face the same problem if the setpoint is say 13 deg C.

This "error" is popping up when these conditions arrise, but normally the actuator goes to its correct maximum possistion to deal with the problem (be it totally open or totally closed), which is correct and as designed.

In your case it may be the impossition of a limit which blocks the actuator from its max position which causes the fatal...

I'm just guessing all of this.

Jean

Sent from my iPhone (excuse the brevity)

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On 12.07.2013, at 04:48, "cadbury.sweety" <cadbury.sweety@xxxxxxxxx> wrote:

Hi I am facing a severe fatal error with my program. The error is
** Severe ** FindRootSimpleController: Root finder failed at RUNPERIOD, 16:00:00.0 - 16:15:00.0
** ~~~ ** Controller name=AHU COOLING COIL CONTROLLER
** ~~~ ** Controller action="" action
** ~~~ ** Root candidate x=9.998979999999999E-009 does not lie within the lower/upper brackets.
** ~~~ ** Upper bracket is x=0.000000000000000
** Fatal ** Preceding error causes program termination.
...Summary of Errors that led to program termination:
..... Reference severe error count=1
..... Last severe error=FindRootSimpleController: Root finder failed at RUNPERIOD, 16:00:00.0 - 16:15:00.0

I tried debugging in the code but couldn't find what exactly is making it crash. If anyone could help me in this it would be really grateful.

Thanks in advance!