Re: [EnergyPlus_Support] HVAC loop Controls

2013/5/6 Griffith, Brent <brent.griffith@xxxxxxxx>

The program will accept such input and try to run. But this input is not going to work very well and will lead to the coils fighting each other if those schedules are constant 12C and 35C.   The cooling coil will open up water flow to try and hit 12C while the heating coil will open up flow to try and hit 35C. The two controllers operate independently of each other. Unless you want to model a fault, or have some clever variations in the schedules, this input is not going to work well. Further there aren?t really air terminal models that are set up to switch between 12C and 35C deck temperatures and still control the zone.

The cooling coil controller would work better if the sensor is at the outlet of the cooling coil instead of downstream. With the heating coil located in between the cooling coil and its sensor, it will have difficulties to make setpoint whenever the heating coil is on.

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Santiago Velez
Sent: Monday, May 06, 2013 7:32 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] HVAC loop Controls - Need help

Dear group, I have some doubts about how HVAC loops controls work. I've modeled an AHU with cooling and heating water coils (Branch and controller object below). I was wondering how to set setpointmanager objects to control water coils so that supply air temperature is 12 C when cooling and 35 C when heating. I now how to do this with zone reheat coils, but I want to make sure I understand how control work.

Is it ok to set 2 Setpointmanagers objects, one for cooling and one heating, that set different temperatures to different nodes, (eg. NCUTA-6 Supply Side Outlet 1 set-point 12 C, and NCUTA-6 AHU Heating Coil Air Outlet Node set-point to 35 C for heating)?

Thanks in advance.

Santiago

Branch,

NCUTA-6 AHU Main Branch, !- Name
autosize, !- Maximum Flow Rate {m3/s}

, !- Pressure Drop Curve Name
Fan:ConstantVolume, !- Component 1 Object Type

NCUTA-6 AHU Extract Fan, !- Component 1 Name
NCUTA-6 Supply Side Inlet, !- Component 1 Inlet Node Name

NCUTA-6 AHU Extract Fan Air Outlet Node, !- Component 1 Outlet Node Name
Active, !- Component 1 Branch Control Type

AirLoopHVAC:OutdoorAirSystem, !- Component 2 Object Type
NCUTA-6 AHU Outside air system, !- Component 2 Name

NCUTA-6 AHU Extract Fan Air Outlet Node, !- Component 2 Inlet Node Name
NCUTA-6 AHU Mixed Air Outlet, !- Component 2 Outlet Node Name

Passive, !- Component 2 Branch Control Type
Coil:Cooling:Water, !- Component 3 Object Type

NCUTA-6 AHU Cooling Coil,!- Component 3 Name
NCUTA-6 AHU Mixed Air Outlet, !- Component 3 Inlet Node Name

NCUTA-6 AHU Cooling Coil Air Outlet Node, !- Component 3 Outlet Node Name
Passive, !- Component 3 Branch Control Type

Coil:Heating:Water, !- Component 4 Object Type
NCUTA-6 AHU Heating Coil,!- Component 4 Name

NCUTA-6 AHU Cooling Coil Air Outlet Node, !- Component 4 Inlet Node Name
NCUTA-6 AHU Heating Coil Air Outlet Node, !- Component 4 Outlet Node Name

Passive, !- Component 4 Branch Control Type
Fan:ConstantVolume, !- Component 5 Object Type

NCUTA-6 AHU Supply Fan, !- Component 5 Name
NCUTA-6 AHU Heating Coil Air Outlet Node, !- Component 5 Inlet Node Name

NCUTA-6 Supply Side Outlet 1, !- Component 5 Outlet Node Name
Active; !- Component 5 Branch Control Type

Controller:WaterCoil,

NCUTA-6 AHU Cooling Coil Controller, !- Name
Temperature, !- Control Variable

Reverse, !- Action
Flow, !- Actuator Variable

NCUTA-6 Supply Side Outlet 1, !- Sensor Node Name
NCUTA-6 AHU Cooling Coil Water Inlet Node, !- Actuator Node Name

autosize, !- Controller Convergence Tolerance {deltaC}
autosize, !- Maximum Actuated Flow {m3/s}

0.000; !- Minimum Actuated Flow {m3/s}

Controller:WaterCoil,

NCUTA-6 AHU Heating Coil Controller, !- Name
Temperature, !- Control Variable

Normal, !- Action
Flow, !- Actuator Variable

  NCUTA-6 AHU Heating Coil Air Outlet Node, !- Sensor Node Name
NCUTA-6 AHU Heating Coil Water Inlet Node, !- Actuator Node Name
autosize, !- Controller Convergence Tolerance {deltaC}

autosize, !- Maximum Actuated Flow {m3/s}
0.000; !- Minimum Actuated Flow {m3/s}

AirLoopHVAC:ControllerList,

NCUTA-6 Controllers, !- Name
Controller:WaterCoil, !- Controller 1 Object Type

NCUTA-6 AHU Cooling Coil Controller, !- Controller 1 Name
Controller:WaterCoil, !- Controller 2 Object Type

NCUTA-6 AHU Heating Coil Controller; !- Controller 2

SetpointManager:Scheduled,
Air Loop Setpoint Manager/1/1/1 Heating, !- Name

Temperature, !- Control Variable 35 C
AHU Setpoint Manager Temp Heating, !- Schedule Name

   NCUTA-6 AHU Heating Coil Air Outlet Node; !- Setpoint Node or NodeList Name

SetpointManager:Scheduled,

Air Loop Setpoint Manager/1/1/1, !- Name
Temperature, !- Control Variable 12 C

AHU Setpoint Manager Temp, !- Schedule Name
   NCUTA-6 Supply Side Outlet 1; !- Setpoint Node or NodeList Name

Re: [EnergyPlus_Support] HVAC loop Controls - Need help