Download - Application of Controls
Application of ControlsApplication of Controls
CAV with Humidity ControlCAV with Humidity Control
Application of ControlsApplication of Controls
CAV with Humidity ControlCAV with Humidity ControlCAV AHU dedicated to a special area:CAV AHU dedicated to a special area:
clean roomclean room textile factorytextile factory hospital operating theatrehospital operating theatre computer equipment roomcomputer equipment room
Environment requires humidity control Environment requires humidity control as well as temperature control - as well as temperature control -
energy efficiency is not as importantenergy efficiency is not as important
Application of ControlsApplication of Controls
Return AirReturn Air
OutdoorOutdoorAirAir
Cooling CoilCooling Coil
Chilled WaterChilled WaterValveValve
FanFan Heater ElementsHeater Elements
CAV with Humidity ControlCAV with Humidity ControlTT
HH
Temperature sensor in spaceTemperature sensor in space
Humidity sensor in spaceHumidity sensor in space
Temperature and humidity Temperature and humidity sensors may alternatively be sensors may alternatively be
placed in return air ductplaced in return air duct
Application of ControlsApplication of Controls
CAV with Humidity ControlCAV with Humidity ControlThe valve is controlled by the humidity The valve is controlled by the humidity sensor to achieve the humidity setpoint.sensor to achieve the humidity setpoint.
The heating elements are controlled by The heating elements are controlled by the temperature sensor to reheat the air the temperature sensor to reheat the air
to achieve the temperate setpoint.to achieve the temperate setpoint.
This works if outdoor air is used; if pre-This works if outdoor air is used; if pre-treated air is used, cooling request may treated air is used, cooling request may
be greater than dehumidification be greater than dehumidification request and valve is controlled by request and valve is controlled by
temperature sensor.temperature sensor.
Application of ControlsApplication of Controls
HumidityHumidity TemperatureTemperatureCAV with Humidity ControlCAV with Humidity Control
HH
TT
S.P.S.P.
D.B.D.B.
P.B.P.B.
Cooling CoilCooling CoilCommandCommand
HeatingHeatingCommandCommand
S.P.S.P.
D.B.D.B.
P.B.P.B.
Application of ControlsApplication of Controls
Mechanical ControlsMechanical Controls
Application of ControlsApplication of Controls
Mechanical ControlsMechanical ControlsFCU ControlFCU Control
A temperature A temperature switch in the return switch in the return
air controls the 2 air controls the 2 position valveposition valve
A separate 3 speed A separate 3 speed switch is connected switch is connected
to the fanto the fan
Application of ControlsApplication of Controls
Mechanical ControlsMechanical ControlsFCU ControlFCU Control
A temperature A temperature switch in the switch in the room controls room controls the 2 position the 2 position
valvevalve
The integral 3 The integral 3 speed switch is speed switch is
connected to the connected to the fanfan
Application of ControlsApplication of Controls
Mechanical ControlsMechanical ControlsCondenser FanCondenser Fan
As the condenser As the condenser pressure pressure
increases, a fan increases, a fan is startedis started
As the pressure As the pressure continues to continues to
rise, a second rise, a second fan is startedfan is started
FromFromEvaporatorEvaporator
ToToCompressorCompressor
Application of ControlsApplication of Controls
Mechanical ControlsMechanical ControlsCooling Tower FanCooling Tower Fan
As the As the temperature temperature
increases, the increases, the low speed low speed winding is winding is engagedengaged
As the As the temperature temperature continues to continues to rise, the high rise, the high
speed winding is speed winding is engagedengaged
Application of ControlsApplication of Controls
Mechanical ControlsMechanical ControlsCold RoomCold Room
As the As the temperature temperature
increases, the increases, the compressors are compressors are
brought on in brought on in sequencesequence
Condenser fans Condenser fans controlled based controlled based
on pressureon pressure
C1C1 C2C2 C3C3 C4C4
EvaporatorEvaporator
ColdColdRoomRoom
CondenserCondenser
Application of ControlsApplication of Controls
Mechanical ControlsMechanical ControlsCompressor Compressor
SafetiesSafeties
If the condenser If the condenser pressure is too pressure is too high or too low, high or too low, the compressor the compressor
will be shut will be shut downdown
If the lube oil If the lube oil pressure is too pressure is too
low, the low, the compressor will compressor will be shut downbe shut down
Application of ControlsApplication of Controls
Chiller Plant IntegrationChiller Plant Integration
Application of ControlsApplication of Controls
Chiller Plant IntegrationChiller Plant Integration Single seat user interfaceSingle seat user interface
Consolidation of informationConsolidation of information
Facility wide strategiesFacility wide strategies
Simplify operations / trainingSimplify operations / training
Application of ControlsApplication of Controls
DataportIntegrator
DDCRS232
Local Area Network
Operator Workstation (PC)
NCU
Carrier Comfort Network
Chiller Plant IntegrationChiller Plant Integration
Application of ControlsApplication of Controls
Chiller Plant IntegrationChiller Plant Integration Chilled Water Setpoint / Control PointChilled Water Setpoint / Control Point
Entering/Leaving Chilled Water Temp.Entering/Leaving Chilled Water Temp.
Entering/Leaving Condenser Water Entering/Leaving Condenser Water Temp.Temp.
Evaporator Refrigerant Temperature Evaporator Refrigerant Temperature and Pressureand Pressure
Condenser Refrigerant Temperature Condenser Refrigerant Temperature and Pressureand Pressure
Application of ControlsApplication of Controls
Chiller IntegrationChiller IntegrationDischarge TemperatureDischarge Temperature
Bearing TemperatureBearing Temperature
Motor Winding TemperatureMotor Winding Temperature
Oil Sump TemperatureOil Sump Temperature
Oil Pressure TransducerOil Pressure Transducer
etc....etc....
In brief, anything visible from Control In brief, anything visible from Control Panel.Panel.
Application of ControlsApplication of Controls
Chiller SequencingChiller Sequencing
Application of ControlsApplication of Controls
0
50
100
150
200
250
TONS
1 x 300 TR Chiller
Chiller SequencingChiller Sequencing
Application of ControlsApplication of Controls
0
100
200
300
400
500
600
700
800
TONS
3 x 300 TR Chiller
1 Chiller on
2 Chillers on
3 Chillers on
Chiller SequencingChiller Sequencing
Application of ControlsApplication of Controls
0
100
200
300
400
500
600
700
800
TONS
3 x 300 TR Chiller +30 HP associatedpumps/fans each
1 Chiller on
2 Chillers on
3 Chillers on
Chiller SequencingChiller Sequencing
Application of ControlsApplication of Controls
0
100
200
300
400
500
600
700
800
TONS
3 x 300 TR Chiller +30 HP associatedpumps/fans each
Run 1 ChillerRun 2
Chillers Run 3 Chillers
Chiller SequencingChiller Sequencing
Application of ControlsApplication of Controls
IncreasingLoad
DecreasingLoad
Differential to preventshort cycling
Chiller SequencingChiller Sequencing
Application of ControlsApplication of Controls
Chiller SequencingChiller Sequencing1. Plot curves for all combinations of 1. Plot curves for all combinations of
chillerschillers including pumps and cooling towers including pumps and cooling towers
2. Take switchover points from graph2. Take switchover points from graph
3. Program switchover points with 3. Program switchover points with differentialdifferential
4. Use run time to choose lead and lag 4. Use run time to choose lead and lag chillers chillers
Application of ControlsApplication of Controls
Chilled Water ResetChilled Water Reset
AHU 1
AHU 3
AHU 2
60%
75%
70%
Valve
6 Degrees
1000 Tons723 kW
Application of ControlsApplication of Controls
Chilled Water ResetChilled Water Reset
Application of ControlsApplication of Controls
AHU 1
AHU 3
AHU 2
60%
75%
70%
Valve
6 Degrees
1000 Tons723 kW
7 Degrees
68%
80%
76%658 kW
Chilled Water ResetChilled Water Reset
Application of ControlsApplication of Controls
56
58
60
62
64
66
68
Time
Chilled Water ResetChilled Water Reset
Application of ControlsApplication of Controls
RatioRatio Max. Reset*Max. Reset*
AHU 1AHU 1 8%/Deg8%/Deg 9.1 Deg 9.1 Deg
AHU 2AHU 2 6%/Deg6%/Deg 8.5 Deg 8.5 Deg
AHU 3AHU 3 5%/Deg5%/Deg 8.0 Deg 8.0 Deg* Assuming maximum valve position allowed is 85%
Chilled Water ResetChilled Water Reset
Application of ControlsApplication of Controls
Chilled Water ResetChilled Water Reset1. Record step response of valve position 1. Record step response of valve position
forfor each AHU to measure system delay and each AHU to measure system delay and calculate ratio (%/Degree) calculate ratio (%/Degree)
2. Automatically reset chilled water 2. Automatically reset chilled water temperature temperature
3. Look for opportunities to add localized 3. Look for opportunities to add localized cooling to increase chiller savings cooling to increase chiller savings