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Introduction to Building Automation Systems (BAS)

3/11/20131 Introduction to Building Automation Systems (BAS) Ryan R. Hoger, LEED R. Hoger, LEED Automation SystemszCentralized controlszChange scheduling for multiple HVAC units at same timezMonitor health of equipmentzInternet accessiblezAlarming via text msg or emailzCollect/trend datazIntegrate to lighting control or security system3/11/20132 What is DDC?zDDC -Direct Digital Controlof an HVAC systemzA method of monitoring and controlling HVAC system performance by collecting, processing, and sending information using sensors, actuators, and is DDC?zDDC is the conceptor theory of HVAC system control that uses digital controlszPhysically, DDC encompasses all the devices used to implement this control method: a whole group of DDC controllers/microprocessors, actuators, sensors, and other - the Control Theoryinput-process-output cycleWhat Is a Point?

3/11/2013 1 Introduction to Building Automation Systems (BAS) Ryan R. Hoger, LEED AP 708.670.6383 ryan.hoger@tecmungo.com Building Automation Systems zCentralized controls zChange scheduling for multiple

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Transcription of Introduction to Building Automation Systems (BAS)

1 3/11/20131 Introduction to Building Automation Systems (BAS) Ryan R. Hoger, LEED R. Hoger, LEED Automation SystemszCentralized controlszChange scheduling for multiple HVAC units at same timezMonitor health of equipmentzInternet accessiblezAlarming via text msg or emailzCollect/trend datazIntegrate to lighting control or security system3/11/20132 What is DDC?zDDC -Direct Digital Controlof an HVAC systemzA method of monitoring and controlling HVAC system performance by collecting, processing, and sending information using sensors, actuators, and is DDC?zDDC is the conceptor theory of HVAC system control that uses digital controlszPhysically, DDC encompasses all the devices used to implement this control method: a whole group of DDC controllers/microprocessors, actuators, sensors, and other - the Control Theoryinput-process-output cycleWhat Is a Point?

2 ZA pointis ANY input or output device used to control the overall or specific performance of equipment or output devices related to the Kinds of PointszAnalog input-a sensorthat monitors physical data, such as temperature, flow, or input-a sensorthat monitors status. Momentary and maintained switches, ON-OFF equipment status, and digital pulses from flow and electric power meters are discrete output- a physical action of a proportional device in the controlled equipment - , actuator opens air damper from 20% to 40%, other dampers, valves, inlet guide vanes, output- changes or maintains device status.

3 Performs momentary or maintained switching for start/stop of pumps, fans, two-position dampers, and on/off : Actions and ReactionsInputsensors and status devices react tochanges in conditions. Conditions include internal load, outside air temperature, and output cooling coil valve (output action). Supply air temperature sensor SAT detects (input reaction) decrease in actbased onsensor and status device 1:Ex. 2:Filters on an air handler get dirty (conditions). Air switch reacts by closing contact for filter dirty Point Identification ExerciseSensor and Status Devices used as Input Points (Reactions)zTemperature Thermistors Resistance Temp.

4 Detectors (RTDs) TransmitterszPressure zHumidityzFlow (CFM, GPM)zVoltagezCurrent zCO2 AIDIzSwitch dry contact (open or closed) Airflow Water Differential pressurezHigh/low limit switch(alarm or normal) Freeze alarm Smoke detectorszWattmeter pulses (pulse initiator or counter)3/11/20136 Devices used as Output Points (Actions)zDamper actuatorszModulating valveszVFDAODOzSolenoid valveszRelays / contactorszAlarm signalDDC: Closed Loop ControlClosed Loop Controlis accomplished by the control signal being sent to the controlled device with constant feedback from the sensor/status device providing input to the Loop ControlzControl algorithms zConfiguration valueszTime schedule data zSetpoint schedule dataClosed loop control is determined by.

5 Typical Control Algorithms Heating/cooling coil control Humidification/dehumidification Mixed air damper optimization VAV fan control VAV supply & return fan tracking Indoor air quality Generic PID control Control point reset3/11/20138 Typical Control Algorithms (cont d) Time of day scheduling Discrete device controlled as analog Discrete interlock Discrete staging Proportional thermostat Primary/secondary pump control Night free cooling Adaptable start/stop Permissive interlockAlgorithm Type Used by Processor Determines Control StrategyProportionalProportional-Integra l Proportional-Integral-DerivativePPIPID3/ 11/20139 What Is PID Control?

6 ZWhat it is:This type of control algorithm is based on value/amount (proportion), rate of change (integral), and error allowances (derivative). PID control calculates and sends commands for outputs based on all three types of :More precise than P and PI controls, PID wastes less energy based on more frequent feedback and quicker = Proportional-Integral-Derivative ControlProportional Control (P)zWhat it is:Control algorithm based only on value/amount (proportion). zDisadvantages:Less precise than PID and PI control; cannot respond to error margins or time. Uses the most energy due to over- and under- Control (PI) & (PID)zWhat it is:Control algorithm based on value/amount (proportion), rate of change (integral).

7 PID uses error allowances (derivative) as well. zAdvantages:More precise control and less energy used than proportional (P); minimum swings from 1: Building Direct Digital Control on a CV Air Handler 3/11/201311 Exercise 1: Base CV Air Handler Unit -No ControlsExercise 1: AHU - DDC Control of Start / Stop Scheduling3/11/201312 Exercise 1: AHU - Add DDC Damper Exercise 1: AHU - Add DDC Cooling Coil Control3/11/201313 Exercise 1: AHU - Add DDC Outside Air reset and Enthalpy Control3/11/201314 Control Point Summary for Base CV AHUE xercise 2: Building Direct Digital Control on a VAV Air Handler 3/11/201315 HistoryzVAV Systems came into favor for mid and large size facilities in the 1960s and 1970s Save energy Improve comfort Take advantage of Building diversity Cooling needed year round for true interior core zoneszSequence Main AHU provides morning warm-up heat until RAT setpoint is satisfied all zones at 100% design airflow AHU switches to 55 F discharge air controlled cooling zones modulate CFM to controls space temp No AHU heat remainder of day individual zone reheat or baseboard as neededZoning Systems3/11/201316 Single Zone

8 SystemsZCZONE 1 TMTTMTMZONE 2 ZONE 3 ZONE 4 ROOFH eating/CoolingUnitHeating/CoolingUnitHea ting/CoolingUnitHeating/CoolingUnitTMMul tiple Zone Systems3/11/201317To Build DDC on a VAV AHU, Start with DDC on a CV * If using VFD, use two Variable Frequency Drives instead, but you will still need the same control points and HPS 2: Create a VAV AHU with Inlet Guide3/11/201318 Typical DDC Items You Can Add as Optional Items: Filter Status (FLTS) FreezeStat (FRZ) Smoke Detector (SMK)Exercise 2: VAV AHU with DDC Filter Status3/11/201319 Exercise 2: VAV AHU with DDC FreezeStatExercise 2: VAV AHU with DDC Smoke Detector3/11/201320 Control Point Summary for Base VAV AHUDDC ControllersProgrammable controllersApplication Specific controllersFactory integrated controllers3/11/201321 Types of Direct Digital Control NetworksInterfaces to DDCzInterface- devices and software that work as a translator between a DDC system and the humans who operate interface is the operator s window into a Building s operating Systems and Interface Benefits Allow more efficient system operation monitoring.

9 You can look at what s happening on all floors from the tenth floor if DDC network is peer-to-peer. Allow immediate diagnosis of HVAC units and controls, including changes, without physically being in front of the unit. Can provide reports ( , historical, consumable, run times, system activity) to be used as records of Building operations. Can provide graphical representations of the controlled interfaces:User Interface Types3/11/201323 Interface ExamplesHand-held Connected to a DDC ControllerInterface ExamplesPC Connected to a DDC Network3/11/201324 Interface ExamplesWeb Server Connected to DDC NetworkWeb InterfaceszStandard web browser or WAP accesszView system statuszAccess schedules and setpointszTrending, alarming.

10 ReportingzReal time interactive graphics3/11/201325 FLOOR PLAN GRAPHICSEQUIPMENT GRAPHICS3/11/201326 EQUIPMENT GRAPHICSFLEXIBLE SCHEDULING3/11/201327 TRENDINGI nternet ThermostatszLow cost alternative to BASzDirect to EthernetzNo PC software uses standard web browserzNo access feeszText/email alerts3/11/201328 Internet ThermostatsInternet Thermostats3/11/201329 Phone Apps for ThermostatszInformation Transfer Add new HVAC equipment to an existing Building Management SystemzCommon User InterfacezBuilding Integration Lighting, HVAC, Security, Fire & Life Safety Enterprise Integration-Utilities, FinancialIntegration3/11/201330 Building Management SystemsPowerMeteringLightingSecurityHVAC C ommon ProtocolsPTMODBUS PTPT3/11/201331 InteroperabilityInteroperabilityis the ability of different devices from the same or different manufacturers to function accurately protocol- a set of guidelines for commands, inputs, and output encoding to create a universal language for all DDC devices.


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