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Introduction to HVAC Controls. Presented by: Diwanshu Shekhar 01/17/2012. Agenda. Introduction HVAC and HVAC Controls Robotics and HVAC Controls Types of HVAC Controls Fundamentals Working Principle HVAC System Overview Common Types VAV System Controls Q and A Session. - PowerPoint PPT Presentation
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Introduction to HVAC Controls
Presented by:
Diwanshu Shekhar01/17/2012
Agenda
IntroductionHVAC and HVAC ControlsRobotics and HVAC Controls
Types of HVAC ControlsFundamentals Working Principle
HVAC SystemOverviewCommon Types
VAV System ControlsQ and A Session
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Abbreviations
HVAC = Heating Ventilation and Air-ConditioningVAV = Variable Air VolumeSP = Set-pointCFM = Cubic Feet per Minute
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
HVAC
Heating
•Heat the living space in the cold weather
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
HVAC
Heating
• Heat the living space in the cold weather
Air-Conditioning
• Cool the living space in the hot weather
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
HVAC
Heating
• Heat the living space in the cold weather
Ventilation
• Maintain indoor air quality
Air-Conditioning
• Cool the living space in the hot weather
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
HVAC Controls
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Heating, Ventilation & Air-Conditioning
Maintain desirable human comfort level
in the living space
HVAC Controls
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Heating, Ventilation & Air-Conditioning
HVAC Control System
Maintain desirable human comfort level
in the living space
Robotics and HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
•Tactile •VisionSensor MotherboardController MotorActuator
Robotics
Robotics and HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
•Tactile •VisionSensor MotherboardController MotorActuator
•Temperature •Pressure•Humidity•Motion Sensor
Sensor•Pneumatic
•Direct Digital Controller
•Damper
•ValvesActuator
Robotics
HVAC
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Compares the sensed temp with the user-defined desired value
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Compares the sensed temp with the user-defined desired value
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
ActuatorCompares the sensed temp with the user-defined desired value
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Actuator
Controlled Variable
Compares the sensed temp with the user-defined desired value
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Actuator
Controlled Variable
Compares the sensed temp with the user-defined desired value
Elementary HVAC Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Actuator
Controlled Variable
Compares the sensed temp with the user-defined desired value
Set-point
Types
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
•Proportional (P)•Proportional Integral (PI)•Proportional Integral Derivative (PID)
Types - Proportional
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Modulating
Cont
rolle
d Va
riabl
e
O = A + K . e
Controller Output
Constant equal to the value of controller output w/ no error
Proportional gain constant
Difference between SP and Controlled Variable
Types – Proportional Integral
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Modulating and Reset – less drift each cycle
Cont
rolle
d Va
riabl
e
O = A + K . E + Ki . Int (edt)
Controller Output
Constant equal to the value of controller output w/ no error
Proportional gain constant
Difference between SP and Controlled Variable
Integral gain constant
Types – Proportional Integral Derivative
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Modulating ,Reset and Rate – less drift each cycle and faster response to get to set-point
Cont
rolle
d Va
riabl
e
O = A + K . E + Ki . Int (edt) + Kd de/dt
Controller Output
Constant equal to the value of controller output w/ no error
Proportional gain constant
Difference between SP and Controlled Variable
Integral gain constant
Derivative gain constant
HVAC System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
HVAC System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Water-Side System
Air-Side System
HVAC System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Water-Side System
Air-Side System
Hot Water SystemCold Water System
Types of HVAC System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Constant Volume System Supply air to the living space at a constant rate, but vary temperature (air-side system)Supply water to the coil at a constant rate, but vary the temperature (water-side system)Variable Volume System - Supply air to the living space at a variable rate, but a constant temperature (air-side system)Supply water to the coil at a variable rate, but a constant temperature (water-side system)
Variable Air Volume System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Outdoor Air Control System
Supply Air Temperature Control System
Air Volume Control System
Variable Air Volume System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Outdoor Air Control System
Supply Air Temperature Control System
Air Volume Control System
Terminal Box
VAV – Outdoor Air Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Out
door
Air
Volu
me
Flow
Rat
e
CO2 level in living space
VAV – Outdoor Air Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Out
door
Air
Volu
me
Flow
Rat
e
CO2 level in living space
VAV – Outdoor Air Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Out
door
Air
Volu
me
Flow
Rat
e
CO2 level in living space
VAV – Supply Air Temperature Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Chill
ed W
ater
Flo
w R
ate
Supply Air Temperature
Maximum capacity of chilled water flow rate
VAV – Supply Air Temperature Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Chill
ed W
ater
Flo
w R
ate
Supply Air Temperature
Maximum capacity of chilled water flow rate
Supply Air Temperature Set-point
VAV – Air Volume Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Zone Air Temperature
Zone
Sup
ply
Air F
low
VAV – Air Volume Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Zone Air Temperature
Zone
Sup
ply
Air F
low
Minimum zone supply air flow rate
VAV – Air Volume Control System
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Zone Air Temperature
Zone
Sup
ply
Air F
low
Minimum zone supply air flow rate
Thermostat Set-point
Q & A
IntroductionTypes of HVAC Controls HVAC System VAV SystemQ and A Session
Contact:Diwanshu ShekharNational Renewable Energy Laboratorydiwanshu.shekhar@nrel.gov----------------------------Additional Resources:www.ashrae.orgwww.uccsuiouee.orgwww.newbuildings.orgControl Systems for Heating, Ventilation Air-Conditioning, ISBN 978-0-387-30521-9
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