Transcript EnergyPlus Training Part 1

Lecture 19: HVAC Outside Air
Systems and Modeling
Guidelines
Material prepared by GARD Analytics, Inc. and University of Illinois
at Urbana-Champaign under contract to the National Renewable Energy
Laboratory. All material Copyright 2002-2003 U.S.D.O.E. - All rights reserved
Purpose of this Lecture
Discuss Outside Air


IAQ requirements force us to draw fresh air
in from the outside environment
Outside air (OA) can have a significant
impact on the building energy
requirements
Show how OA is specified in EnergyPlus
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Keywords Covered in this Lecture
Air Loop Equipment List
Outside Air System
Outside Air Mixer
Controller:Outside Air
Outside Air Inlet Node List
Review of other related keywords
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Components: Special Case Outside Air System
OUTSIDE AIR SYSTEM is a subsystem
component
OA System Controller List
OA System Equipment List
OA System Availability Manager List
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OA System Equipment List
System component type

outside air mixer, coil, heat exchanger
System component name
Repeat for each air loop component
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Air Loop Equipment List Example
AIR LOOP EQUIPMENT LIST,
OA Sys 1 Equipment, !- Name
OUTSIDE AIR MIXER,
!- KEY--System Component 1
OA Mixing Box 1;
!- Component Name 1
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Outside Air System - Example
OUTSIDE AIR SYSTEM,
OA Sys 1,
OA Sys 1 Controllers,
OA Sys 1 Equipment,
VAV Sys 1 Avail List;
!!!!-
Name
Name: Controller List
Name of an Air Loop Equipment List
Name of a System Availability Manager List
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Outside Air Mixer
Mixed_Air_Node
Outside_Air_Stream_Node
Relief_Air_Stream_Node
Return_Air_Stream_Node
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Outside Air Mixer - Example
OUTSIDE AIR MIXER,
OA Mixing Box 1,
Mixed Air Node 1,
Outside Air Inlet Node 1,
Relief Air Outlet Node 1,
VAV Sys 1 Inlet Node;
!!!!!-
Name
Mixed_Air_Node
Outside_Air_Stream_Node
Relief_Air_Stream_Node
Return_Air_Stream_Node
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Outside Air Mixer – Controller
List
CONTROLLER LIST,
OA Sys 1 Controllers,
CONTROLLER:OUTSIDE AIR,
OA Controller 1;
!- Name
!- Controller Type 1
!- Controller Name 1
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Controller:Outside Air
Control_Node
Actuated_Node
Minimum outside air flow rate
Maximum outside air flow rate
Temperature limit
Temperature lower limit
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Controller:Outside Air Example
CONTROLLER:OUTSIDE AIR,
OA Controller 1,
ECONOMIZER,
NO RETURN AIR TEMP LIMIT,
NO RETURN AIR ENTHALPY LIMIT,
NO LOCKOUT,
FIXED MINIMUM,
Mixed Air Node 1,
Outside Air Inlet Node 1,
autosize,
autosize,
19.,
4.,
0.0,
Relief Air Outlet Node 1,
VAV Sys 1 Inlet Node,
Min OA Sched;
!!!!!!!!!!!!!!!!-
Name
EconomizerChoice
ReturnAirTempLimit
ReturnAirEnthalpyLimit
Lockout
MinimumLimit
Control_Node
Actuated_Node
min outside air flow rate {m3/s}
max outside air flow rate {m3/s}
temperature limit {C}
temperature lower limit {C}
enthalpy limit {J/kg}
Relief_Air_Outlet_Node
Return_Air_Node
Minimum Outside Air Schedule Name
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TermReheat with Outside Air
Example
Supply Fan
Outside Air
 Air Loop contains the Mixed Air
CC
Mixed Outside
Air Box
System
Relief Air
Resistive
Return Air Mixer
VAV Box: ReHeat
East
Zone Air Splitter
Zone
Zone
VAV Box: ReHeat
North
Zone
VAV Box: ReHeat
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TermReheat
Main Branch with OA System
Outside Air
Supply Fan
CC
Mixed Outside
Air Box
Relief Air
BRANCH,
Air Loop Main Branch,
1.3,
OUTSIDE AIR SYSTEM,
OA Sys 1,
VAV Sys 1 Inlet Node,
Mixed Air Node,
PASSIVE,
FAN:SIMPLE:ConstVolume,
Supply Fan 1,
Mixed Air Node,
< cooling coil >
!!!!!!!!!!-
Branch Name
Maximum Branch Flow Rate {m3/s}
Comp1 Type
Comp1 Name
Comp1 Inlet Node Name
Comp1 Outlet Node Name
Comp1 Branch Control Type
Comp2 Type
Comp2 Name
Comp2 Inlet Node Name
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TermReheat
Outside Air Node List
Outside Air
Mixed Outside
Air Box
Relief Air
OUTSIDE AIR INLET NODE LIST,
OutsideAirInletNodes;
!- 1st Node name or node list name
NODE LIST,
OutsideAirInletNodes,
!- Node List Name
Outside Air Inlet Node 1;
!- Node_ID_1
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TermReheat
Outside Air System
Outside Air
Mixed Outside
Air Box
Relief Air
OUTSIDE AIR SYSTEM,
OA Sys 1,
!- Name
OA Sys 1 Controllers,
!- Name: Controller List
OA Sys 1 Equipment,
!- Name of an Air Loop Equipment List
VAV Sys 1 Avail List;
!- Name of a System Availability Manager List
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TermReheat
Outside Air Controller List
Outside Air
Mixed Outside
Air Box
Relief Air
CONTROLLER LIST,
OA Sys 1 Controllers,
!- Name
CONTROLLER:OUTSIDE AIR,
!- Controller Type 1
OA Controller 1;
!- Controller Name 1
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TermReheat
Outside Air Equipment List
Outside Air
Mixed Outside
Air Box
Relief Air
AIR LOOP EQUIPMENT LIST,
OA Sys 1 Equipment,
!- Name
OUTSIDE AIR MIXER,
!- KEY--System Component 1
OA Mixing Box 1;
!- Component Name 1
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TermReheat
Outside Air Controller
CONTROLLER:OUTSIDE AIR,
OA Controller 1,
ECONOMIZER,
NO RETURN AIR TEMP LIMIT,
NO RETURN AIR ENTHALPY LIMIT,
NO LOCKOUT,
FIXED MINIMUM,
Mixed Air Node 1,
Outside Air Inlet Node 1,
0.468,
1.56,
19.,
4.,
0.0,
Relief Air Outlet Node 1,
VAV Sys 1 Inlet Node,
Min OA Sched;
!!!!!!!!!!!!!!!!-
Name
EconomizerChoice
ReturnAirTempLimit
ReturnAirEnthalpyLimit
Lockout
MinimumLimit
Control_Node
Actuated_Node
minimum outside air flow rate {m3/s}
maximum outside air flow rate {m3/s}
temperature limit {C}
temperature lower limit {C}
enthalpy limit {J/kg}
Relief_Air_Outlet_Node
Return_Air_Node
Minimum Outside Air Schedule Name
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TermReheat
Outside Air Mixer
Outside Air
Mixed Outside
Air Box
Relief Air
OUTSIDE AIR MIXER,
OA Mixing Box 1,
!- Name
Mixed Air Node 1,
!- Mixed_Air_Node
Outside Air Inlet Node 1,
!- Outside_Air_Stream_Node
Relief Air Outlet Node 1,
!- Relief_Air_Stream_Node
VAV Sys 1 Inlet Node;
!- Return_Air_Stream_Node
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Outdoor Air Economizer
TermReheatOA.idf example file
CONTROLLER:OUTSIDE AIR,
OA Controller 1, !- Name
ECONOMIZER, !- EconomizerChoice
NO RETURN AIR TEMP LIMIT, !- ReturnAirTempLimit
NO RETURN AIR ENTHALPY LIMIT, !- ReturnAirEnthalpyLimit
NO LOCKOUT, !- Lockout
FIXED MINIMUM, !- MinimumLimit
Mixed Air Node, !- Control_Node
Outside Air Inlet Node, !- Actuated_Node
0.4333, !- minimum outside air flow rate {m3/s}
1.3, !- maximum outside air flow rate {m3/s}
19., !- temperature limit {C}
4., !- temperature lower limit {C}
0.0, !- enthalpy limit {J/kg}
Relief Air Outlet Node, !- Relief_Air_Outlet_Node
VAV Sys 1 Inlet Node; !- Return_Air_Node
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Outdoor Air Economizer
(cont’d)
Scheduled mixed air setpoint
SET POINT MANAGER:SCHEDULED,
Mixed Air Temp Manager, !- Name
TEMP, !- Control variable
Seasonal Reset Mixed Air Temp Sch, !- Schedule Name
Mixed Air Nodes; !- Name of the set point Node List
NODE LIST,
Mixed Air Nodes, !- Node List Name
Mixed Air Node; !- Node_ID_1
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Outdoor Air Economizer
(cont’d)
Mixed air setpoint adjusted for fan heat
SET POINT MANAGER:SCHEDULED,
Supply Air Temp Manager 1, !- Name
TEMP, !- Control variable
Seasonal Reset Supply Air Temp Sch, !- Schedule Name
Supply Air Temp Nodes 1; !- Name of the set point Node List
SET POINT MANAGER:MIXED AIR,
Mixed Air Temp Manager 1, !- Name
TEMP, !- Control variable:
VAV Sys 1 Outlet Node, !- reference set point node name
Main Heating Coil 1 Outlet Node, !- fan inlet node name
VAV Sys 1 Outlet Node, !- fan outlet node name
Mixed Air Node 1; !- Name of the set point Node or Node List
NODE LIST,
Supply Air Temp Nodes 1, !- Node List Name
VAV Sys 1 Outlet Node; !- Node_ID_1
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Economizer with Furnace/DX
Furnace/DX does not set a supply air
setpoint
Must use setpoint managers to establish
a setpoint
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Summary
Introduction of outside air into a forced
air system is necessary to meet indoor
air quality (IAQ) standards
Outside air (mixing box) in EnergyPlus
is a component on an air loop branch
Outside air system also contains
controllers that can be operated in
economizer mode
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