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[EnergyPlus_Support] Re: Plant temperatures are getting far too hot
This is almost always where your CHW setpoint is above room temperature, or the HHW setpoint is below, and the pumps are operating. This means, that in your instance, E+ thinks the room is actually rejecting heat into the HHW system and it never gets rejected out so day by day the system HHW temp rises. This happens primarily when you have a night shut off and the room temp gets up to like 85 degF and your HHW set point is below that (lets say you have it at 72degF).
I am assuming you are using an outdoor air reset temp set point, so try raising the bottom end of your set point or look the SetpointManager:Coldest for demand control heating.
Or look at just shutting the heating coil off during the warmest months (which is preferable to turning the pump off since you will still see the temperature of the loop increase IIRC).
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Denilson Espirito Santo <denilsonbes@...> wrote:
>
> Dear Energy+ Group
>
> I`m trying to simulate a four pipe fancoil with an electrical chiller and a boiler.
> I used the fancoilautosize example file as a support.
>
> An error is occurring (see message in the bottom).
>
> Ideas and suggestions are appreciated.
>
>
> Denilson Boschiero do Espirito Santo
>
>
>
>
>
> Severe ** Plant temperatures are getting far too hot, check controls and relative loads and capacities
> ** ~~~ ** Environment=SAO_PAULO/CONGONHAS - BRA SWERA WMO#=837800, at Simulation time=02/20 09:15 - 09:30
> ** ~~~ ** PlantLoop Name (SupplySide)= HOT WATER LOOP
> ** ~~~ ** PlantLoop Setpoint Temperature=82.0 {C}
> ** ~~~ ** PlantLoop Inlet Node (SupplySide) does not have a Setpoint.
> ** ~~~ ** PlantLoop Inlet Node (DemandSide) does not have a Setpoint.
> ** ~~~ ** PlantLoop Outlet Node (SupplySide) has a Setpoint.
> ** ~~~ ** PlantLoop Outlet Node (DemandSide) does not have a Setpoint.
> ** ~~~ ** PlantLoop Outlet Node (SupplySide) "HW SUPPLY OUTLET NODE" has temperature=300.0 {C}
> ** ~~~ ** PlantLoop Inlet Node (SupplySide) "HW SUPPLY INLET NODE" has temperature=300.0 {C}
> ** ~~~ ** PlantLoop Minimum Temperature=10.0 {C}
> ** ~~~ ** PlantLoop Maximum Temperature=100.0 {C}
> ** ~~~ ** PlantLoop Flow Request (SupplySide)=0.0 {kg/s}
> ** ~~~ ** PlantLoop Flow Request (DemandSide)=0.0 {kg/s}
> ** ~~~ ** PlantLoop Node (SupplySide) "HW SUPPLY OUTLET NODE" has mass flow rate =4.7 {kg/s}
> ** ~~~ ** PlantLoop PumpHeat (SupplySide)=1088.7 {W}
> ** ~~~ ** PlantLoop PumpHeat (DemandSide)=0.0 {W}
> ** ~~~ ** PlantLoop Cooling Demand=4379245.5 {W}
> ** ~~~ ** PlantLoop Heating Demand=0.0 {W}
> ** ~~~ ** PlantLoop Demand not Dispatched=0.0 {W}
> ** ~~~ ** PlantLoop Unmet Demand=-4379245.5 {W}
> ** ~~~ ** PlantLoop Capacity=1.2 {W}
> ** ~~~ ** PlantLoop Capacity (SupplySide)=1.2 {W}
> ** ~~~ ** PlantLoop Capacity (DemandSide)=0.0 {W}
> ** ~~~ ** PlantLoop Operation Scheme=HOT LOOP OPERATION
> ** ~~~ ** PlantLoop Operation Dispatched Load = 0.0 {W}
> ** ~~~ ** PlantLoop Operation Dispatched Load (SupplySide)= 0.0 {W}
> ** ~~~ ** PlantLoop Operation Dispatched Load (DemandSide)= 0.0 {W}
> ** ~~~ ** Branches on the Loop.
> ** ~~~ ** Demand Branches:
> ** ~~~ ** ZONESHWINLETBRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** PIPE:ADIABATIC:ZONESHWINLETPIPE
> ** ~~~ ** ZONE1HWBRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** COIL:HEATING:WATER:ZONE1FANCOILHEATINGCOIL
> ** ~~~ ** ZONESHWBYPASSBRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** PIPE:ADIABATIC:ZONESHWBYPASSPIPE
> ** ~~~ ** ZONESHWOUTLETBRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** PIPE:ADIABATIC:ZONESHWOUTLETPIPE
> ** ~~~ ** Supply Branches:
> ** ~~~ ** HEATING SUPPLY INLET BRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** PUMP:CONSTANTSPEED:HW CIRC PUMP
> ** ~~~ ** BOILER BRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** BOILER:HOTWATER:BOILER1
> ** ~~~ ** HEATING SUPPLY BYPASS BRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** PIPE:ADIABATIC:HEATING SUPPLY SIDE BYPASS
> ** ~~~ ** HEATING SUPPLY OUTLET BRANCH
> ** ~~~ ** Components on Branch:
> ** ~~~ ** PIPE:ADIABATIC:HEATING SUPPLY OUTLET
> ** ~~~ ** *************************
> ** ~~~ ** Possible things to look for to correct this problem are:
> ** ~~~ ** Capacity, Operation Scheme, Mass flow problems, Pump Heat building up over time.
> ** ~~~ ** Try a shorter runperiod to stop before it fatals and look at
> ** ~~~ ** lots of node time series data to see what is going wrong.
> ** ~~~ ** If this is happening during Warmup, you can use Output:Diagnostics,ReportDuringWarmup;
> ** ~~~ ** This is detected at the loop level, but the typical problems are in the components.
> ** Fatal ** CheckForRunawayPlantTemps: Simulation terminated because of run away plant temperatures, too hot
> ...Summary of Errors that led to program termination:
> ..... Reference severe error count=1
> ..... Last severe error=Plant temperatures are getting far too hot, check controls and relative loads and capacities
> *************
> ************* ===== Recurring Error Summary =====
> ************* The following recurring error messages occurred.
> *************
> ************* ** Warning ** Plant loop exceeding upper temperature limit, PlantLoop="HOT WATER LOOP"
> ************* ** ~~~ ** This error occurred 12180 total times;
> ************* ** ~~~ ** during Warmup 116 times;
> ************* ** ~~~ ** during Sizing 0 times.
> ************* ** ~~~ ** Max=300.003706
> *************
> ************* ** Warning ** GetDensityGlycol: Temperature out of range (too high) for fluid [WATER] density **
> ************* ** ~~~ ** This error occurred 48560 total times;
> ************* ** ~~~ ** during Warmup 0 times;
> ************* ** ~~~ ** during Sizing 0 times.
> ************* ** ~~~ ** Max=300.019644 {C} Min=103.933878 {C}
> *************
> ************* ** Warning ** GetSpecificHeatGlycol: Temperature out of range (too high) for fluid [WATER] specific heat **
> ************* ** ~~~ ** This error occurred 303231 total times;
> ************* ** ~~~ ** during Warmup 0 times;
> ************* ** ~~~ ** during Sizing 0 times.
> ************* ** ~~~ ** Max=300.019644 {C} Min=125.003494 {C}
> *************
> *************
> ************* ===== Final Error Summary =====
> ************* The following error categories occurred. Consider correcting or noting.
> ************* Nominally Unused Constructions
> ************* ..The nominally unused constructions warning is provided to alert you to potential conditions that can cause
> ************* ..extra time during simulation. Each construction is calculated by the algorithm indicated in the HeatBalanceAlgorithm
> ************* ..object. You may remove the constructions indicated (when you use the DisplayExtraWarnings option).
> *************
> ************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.
> ************* EnergyPlus Sizing Error Summary. During Sizing: 3 Warning; 0 Severe Errors.
> ************* EnergyPlus Terminated--Fatal Error Detected. 363979 Warning; 1 Severe Errors; Elapsed Time=00hr 00min 36.90sec
>
------------------------------------
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