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Re: [EnergyPlus_Support] Hybrid Cooling Tower



Thanks a lot Chandan.

I've submitted a ticket to the dev team earlier today, I will update the list once they get back to me for future reference

Best,
Julien

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13

LinkedIn (en) : www.linkedin.com/in/julienmarrec
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr


2014-08-06 16:40 GMT+02:00 Chandan Sharma chandangsharma@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:
 

Julien,

This could be a bug. E+ development team can tell you better. If for some reason what is attempted here is not a good way to model hybrid cooling tower they will let you know that too. I think what you tried should have worked.

Unfortunately, I can't think of any other way to model this other than maybe user defined plant component. But this is very time consuming specially if you did not work with EMS before.

Sorry, couldn't help you much on this. May be someone else in this forum could shed some light.

Thanks,
Chandan

On 8/5/2014 5:38 PM, Julien Marrec julien.marrec@xxxxxxxxx [EnergyPlus_Support] wrote:
 
Hi,

To summarize, on my condenser loop I've got two branches in parallel: one with a fluid cooler, one with a regular cooling tower. Each branch has a pump and the heat rejection equipment.

I'm trying to use EMS to alternate between the two branches based on a setpoint.

I've tried it two ways:

- As Chandan suggested, assigning a Pump Flow Rate Schedule to the pumps and modifying them with EMS at calling point "BeginTimestepBeforePredictor". The schedules are computer fine but only the fluid cooler runs all the time.

- Using an actuator to override the Pump Mass Flow Rate at calling point "InsideHVACSystemIterationLoop". I've added a binary variable that shows the EMS does run and goes through the IF statements just fine. But only the fluid cooler runs all the time (again).


I've got a good news and a bad news.
The good news is that I'm getting exactly the same results in both cases.
The bad one is that the results are not what I wanted or expected: only the fluid cooler runs, the cooling tower stays off.

Can someone with EMS experience tell me what I'm missing please?

I've attached both files if somebody would care to take a look.

Thanks,
Julien

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13

LinkedIn (en) : www.linkedin.com/in/julienmarrec
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr


2014-08-05 11:32 GMT+02:00 Julien Marrec <julien.marrec@xxxxxxxxx>:
Hi,

I've integrated Chandan's code.

I see that the schedule value is being computed correctly by the EMS program. Nevertheless, it seems that the pump mass flow rates as well as the pump electric power stays constant (if availability schedule is 0, the pump flow rate stays constant).

Can somebody explain why is that happening and how to remedy?

Thanks,
Julien

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13

LinkedIn (en) : www.linkedin.com/in/julienmarrec
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr


2014-08-04 11:30 GMT+02:00 Julien Marrec <julien.marrec@xxxxxxxxx>:

Chandan,

Thanks for this bit of code, I'll try it out as soon as possible, and might have some more questions as I have never used EMS yet.

Best,
Julien

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13
www.julienmarrec.com

DoYouBuzz : www.doyoubuzz.com/julien-marrec_1
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr
LinkedIn (en) : www.linkedin.com/in/julienmarrec


2014-08-02 10:58 GMT+02:00 Chandan Sharma chandangsharma@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:

 
Julien,

Availability managers in plant or air loop will turn on or off the entire loop (not individual dry or evaporative fluid coolers) so they may not serve the purpose in this case. If the dry and evaporative fluid coolers are in parallel branches with their branch pumps, these pumps' schedule can be modified using EMS. (Something like below). You can try and see if this works.

Another lot more time consuming but accurate way could be to use PlantComponent:UserDefined. This object will allow to define the behavior of hybrid cooling tower.

  Branch,
    Condenser Supply Fluidcooler Branch 1,  !- Name
    0,                       !- Maximum Flow Rate {m3/s}
    ,                        !- Pressure Drop Curve Name
    Pump:VariableSpeed,      !- Component 1 Object Type
    Cond Circ Pump 1,          !- Component 1 Name
    Cond Circ Pump 1 Inlet Node,  !- Component 1 Inlet Node Name
    Condenser Fluidcooler Inlet Node,  !- Component 1 Outlet Node Name
    ACTIVE,                  !- Component 1 Branch Control Type
    Fluidcooler:SingleSpeed, !- Component 2 Object Type
    Big FluidCooler,         !- Component 2 Name
    Condenser Fluidcooler Inlet Node,  !- Component 2 Inlet Node Name
    Condenser Fluidcooler Outlet Node,  !- Component 2 Outlet Node Name
    ACTIVE;                  !- Component 2 Branch Control Type

  Branch,
    Condenser Supply Fluidcooler Branch 2,  !- Name
    0,                       !- Maximum Flow Rate {m3/s}
    ,                        !- Pressure Drop Curve Name
    Pump:VariableSpeed,      !- Component 1 Object Type
    Cond Circ Pump 2,          !- Component 1 Name
    Cond Circ Pump 2 Inlet Node,  !- Component 1 Inlet Node Name
    Condenser EvapFluidcooler Inlet Node,  !- Component 1 Outlet Node Name
    ACTIVE,                  !- Component 1 Branch Control Type
    EvaporativeFluidCooler:SingleSpeed, !- Component 2 Object Type
    Big EvaporativeFluidCooler,         !- Component 2 Name
    Condenser EvapFluidcooler Inlet Node,  !- Component 2 Inlet Node Name
    Condenser EvapFluidcooler Outlet Node,  !- Component 2 Outlet Node Name
    ACTIVE;                  !- Component 2 Branch Control Type

  Pump:VariableSpeed,
    Cond Circ Pump 1,          !- Name
    Cond Circ Pump 1 Inlet Node,  !- Inlet Node Name
    Condenser Fluidcooler Inlet Node,  !- Outlet Node Name
    0.001388,                !- Rated Flow Rate {m3/s}
    297500,                  !- Rated Pump Head {Pa}
    500,                     !- Rated Power Consumption {W}
    .87,                     !- Motor Efficiency
    0.0,                     !- Fraction of Motor Inefficiencies to Fluid Stream
    0,                       !- Coefficient 1 of the Part Load Performance Curve
    1,                       !- Coefficient 2 of the Part Load Performance Curve
    0,                       !- Coefficient 3 of the Part Load Performance Curve
    0,                       !- Coefficient 4 of the Part Load Performance Curve
    0,                       !- Minimum Flow Rate {m3/s}
    INTERMITTENT,            !- Pump Control Type
    CondCircPump1PumpAvailSched;   !- Pump Flow Rate Schedule Name

  Fluidcooler:SingleSpeed,
    Big FluidCooler,         !- Name
    Condenser Fluidcooler Inlet Node,  !- Water Inlet Node Name
    Condenser Fluidcooler Outlet Node,  !- Water Outlet Node Name
    NominalCapacity,         !- Performance Input Method
    ,                        !- Design Air Flow Rate U-factor Times Area Value {W/K}
    58601.,                  !- Nominal Capacity {W}
    51.67,                   !- Design Entering Water Temperature {C}
    35,                      !- Design Entering Air Temperature {C}
    25.6,                    !- Design Entering Air Wetbulb Temperature {C}
    0.001388,                !- Design Water Flow Rate {m3/s}
    9.911,                   !- Design Air Flow Rate {m3/s}
    autosize;                !- Design Air Flow Rate Fan Power {W}

  Pump:VariableSpeed,
    Cond Circ Pump 2,          !- Name
    Cond Circ Pump 2 Inlet Node,  !- Inlet Node Name
    Condenser EvapFluidcooler Inlet Node,  !- Outlet Node Name
    0.001388,                !- Rated Flow Rate {m3/s}
    297500,                  !- Rated Pump Head {Pa}
    500,                     !- Rated Power Consumption {W}
    .87,                     !- Motor Efficiency
    0.0,                     !- Fraction of Motor Inefficiencies to Fluid Stream
    0,                       !- Coefficient 1 of the Part Load Performance Curve
    1,                       !- Coefficient 2 of the Part Load Performance Curve
    0,                       !- Coefficient 3 of the Part Load Performance Curve
    0,                       !- Coefficient 4 of the Part Load Performance Curve
    0,                       !- Minimum Flow Rate {m3/s}
    INTERMITTENT,            !- Pump Control Type
    CondCircPump2PumpAvailSched;   !- Pump Flow Rate Schedule Name

  EvaporativeFluidcooler:SingleSpeed,
    Big EvaporativeFluidCooler,  !- Name
    Condenser EvapFluidcooler Inlet Node,  !- Water Inlet Node Name
    Condenser EvapFluidcooler Outlet Node,  !- Water Outlet Node Name
    3.02,                    !- Design Air Flow Rate {m3/s}
    2250,                    !- Design Air Flow Rate Fan Power {W}
    0.002208,                !- Design Spray Water Flow Rate {m3/s}
    UserSpecifiedDesignCapacity,  !- Performance Input Method
    ,                        !- Outdoor Air Inlet Node Name
    ,                        !- Heat Rejection Capacity and Nominal Capacity Sizing Ratio
    ,                        !- Standard Design Capacity {W}
    ,                        !- Design Air Flow Rate U-factor Times Area Value {W/K}
    0.001703,                !- Design Water Flow Rate {m3/s}
    87921,                   !- User Specified Design Capacity {W}
    46.11,                   !- Design Entering Water Temperature {C}
    35,                      !- Design Entering Air Temperature {C}
    25.6;                    !- Design Entering Air Wet-bulb Temperature {C}


  Schedule:Compact,
    CondCircPump1PumpAvailSched,   !- Name
    Fraction,                !- Schedule Type Limits Name
    Through: 12/31,           !- Field 1
    For: AllDays,            !- Field 2
    Until: 24:00,0.0;        !- Field 3

  Schedule:Compact,
    CondCircPump2PumpAvailSched,   !- Name
    Fraction,                !- Schedule Type Limits Name
    Through: 12/31,           !- Field 1
    For: AllDays,            !- Field 2
    Until: 24:00,0.0;        !- Field 3

  EnergyManagementSystem:Actuator,
    Set_CondCircPump1Avail_Sched, !- Name
    CondCircPump1PumpAvailSched, !- Actuated Component Unique Name
    Schedule:Compact,            !- Actuated Component Type
    Schedule Value;              !- Actuated Component Control Type

  EnergyManagementSystem:Actuator,
    Set_CondCircPump2Avail_Sched, !- Name
    CondCircPump2PumpAvailSched, !- Actuated Component Unique Name
    Schedule:Compact,            !- Actuated Component Type
    Schedule Value;              !- Actuated Component Control Type

  EnergyManagementSystem:ProgramCallingManager,
    My Setpoint Schedule Calculator Example,
    BeginTimestepBeforePredictor,
    Set_CondCircPumpAvail_Sched_Prog;

  EnergyManagementSystem:Sensor,
    OutdoorTemp,                           !- Name
    Environment,                           !- Output:Variable Index Key Name
    Site Outdoor Air Drybulb Temperature;  !- Output:Variable Name

  EnergyManagementSystem:Program,
Set_CondCircPumpAvail_Sched_Prog,
IF (OutdoorTemp <= 18.33 && OutdoorTemp > 0.0),
 Set Set_CondCircPump1Avail_Sched = 1.0 ,
 Set Set_CondCircPump2Avail_Sched = 0.0 ,
ELSEIF (OutdoorTemp > 21.0),
 Set Set_CondCircPump1Avail_Sched = 0.0 ,
 Set Set_CondCircPump2Avail_Sched = 1.0 ,
ENDIF;

  Output:Variable,CondCircPump1PumpAvailSched,Schedule Value,timestep;
  Output:Variable,CondCircPump2PumpAvailSched,Schedule Value,timestep;

  Output:Variable,Cond Circ Pump 1,Pump Electric Power,timestep;
  Output:Variable,Cond Circ Pump 1,Pump Mass Flow Rate,timestep;
  Output:Variable,Cond Circ Pump 2,Pump Electric Power,timestep;
  Output:Variable,Cond Circ Pump 2,Pump Mass Flow Rate,timestep;


On Fri, Aug 1, 2014 at 10:17 PM, Julien Marrec julien.marrec@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
 
Hi,

Has anyone successfully modeled an hybrid cooling tower in E+?
By hybrid I mean running dry until a switchover temperature. When the outdoor dry bulb is above, say, 65°F, you start spraying.

How would you do it?

Should I use for example one CoolingTower:TwoSpeed and one FluidCooler:TwoSpeed and turn them on/off based on outdoor temperature using an availabilitymanager?


Thanks for any insight you can provide.

Best,
Julien

--
Julien Marrec, EBCP, BPI MFBA
Energy&Sustainability Engineer
T: +33 6 95 14 42 13
www.julienmarrec.com

DoYouBuzz : www.doyoubuzz.com/julien-marrec_1
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr
LinkedIn (en) : www.linkedin.com/in/julienmarrec








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Posted by: Julien Marrec <julien.marrec@xxxxxxxxx>


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