DDC Controls and Software for the HVACR Lab. by Greg Jourdan Wenatchee Valley College Las Vegas, Nevada March th, :30-4 PM

Transcription

1 DDC Controls and Software for the HVACR Lab by Greg Jourdan Wenatchee Valley College Las Vegas, Nevada March th, :30-4 PM 1

2 DDC Controls and Software for the HVAC Lab Agenda 1. Types and Level of Automation 2. HVAC DDC Control Principles 3. Open Protocol Control Principles 4. DDC Architecture 5. Examples of DDC Software Programs 6. Typical DDC Control Systems and Applications 7. Present and Future Trends in DDC Controls 8. Getting DDC Equipment in your Schools

3 DDC Controls Quiz 1. T F DDC and PLC s are basically the same control devices. 2. T F There are 3 key components of any DDC controls system. 3. T F BACNet, Lon, and Tridium are Open Software DDC Integration Tools 4. T F The thermistor is linear like the RTD. 5. T F The Boolean Point is used for converting temperature sensors into useful information.

4 The Various Levels of DDC and Automation Residential and Home Automation Smart Homes, not widely adopted with HVAC Manufacturer s Equipment Smart HVAC Systems, ie. Carrier, Nordyn Commercial DDC is Designed for Commercial Buildings Multiple Vendors Industrial PLC s, SCADA, Ladder Logic, Costly $$$

5 Residential and Home Automation

6 Commercial DDC Automation

7 Present DDC Control Vendors and Merger Corporations Schneider

8 Industrial Automation

9 Evolution of Controls and DDC

10 PC Based DDC Control System Trunk / Network Cable Field Panel 1 Field Panel 2 Field Panel 3 LAN Devices LAN Devices

11 Modern DDC Building Controls Utilize a Four Level Architecture

12 Sensor Level

13 Field Controller Level

14 Integration Level

15 Management Level

16 The Purpose of any Temperature Control System Control systems are the brains of HVAC equipment to maintain human comfort. Pictured below is an AHU that serves only one zone. This type of AHU is called a single zone AHU. In the example, a temperature sensor (stat) sends a signal to a control panel, which sends a signal to a valve.

17 Three (3) Key Components of any Control System Include:

18 DDC Terminology Set Point and Offset Set point is the desired condition of a variable that is to be maintained, such as temperature. In the example below, 75 degrees F. is the room temperature set point. Offset is the amount of difference between control point and set point in a proportional control system. In the example below, the offset is approximately 4 F.

19 DDC Terminology Control Point The Control Point is the actual temperature being sensed. The Control Point (temperature) may not be on the set point, but instead may be above or below it. Simply stated, set point is what you want, while control point is what you get.

20 DDC Terminology Throttling Range System Throttling Range (STR) is the change in the measured variable (i.e. temperature) that causes the controlled device to travel from one end of its stroke to the other.

21 The DDC Control Cycle and Control Action Can be Very Accurate Two Position Floating Action Proportional Action PI PID

22 Control Cycle Graph

23 Two Position (Old School-Not Accurate) Two Position control action chart (heating action shown)

24 Floating Action Control Floating Control Action

25 Proportional Action Proportional Control Action

26 Proportional with Integral Control (PI) Proportional Plus Integral (PI) Control Action

27 PID-Proportional Plus Integral & Derivative Proportional Plus Integral Plus Derivative (PID) control action

28 Control Points for the DDC System Four Types of Point Data Categories Boolean - Represents a binary value with only two states, such as "Off" or "On." Numeric - Represents an analog value such as a temperature, level, rate or similar floating point number, or a varying count (integer). Enum - Represents an enumerated state (more than two), such as a multi-speed fan with states "Off," "Slow," and "Fast." Enums are often called multi-states or discretes. String - A string of one or more ASCII characters and often (if alpha-numeric) with some literal meaning.

29 Control Points for the DDC Eight Types of Control Points Boolean Numeric Enumerated String BooleanPoint NumericPoint EnumPoint StringPoint A read only point Facets Proxy Extension Out A read only point Facets Proxy Extension Out A read only point Facets Proxy Extension Out A read only point Facets Proxy Extension Out BooleanWritable NumericWritable EnumWritable StringWritable Extended to include Priority controls Fallback property Override expiration 7 Commands On & Off timers Extended to include Priority controls Fallback property Override expiration 5 Commands Extended to include Priority controls Fallback property Override expiration 5 Commands Extended to include Priority controls Fallback property Override expiration 5 Commands 29

30 Sensors A sensor monitors and measures a variable. The HVAC variables are temperature, humidity, flow, and pressure. Different types of signals are produced by different types of sensors. They include: Electric Sensors Pneumatic Sensors Electronic Sensors Examples of a sensor is shown here. While it may appear to be a thermostat, it is a remote sensor with a remote set point dial. The controller is in another location.

31 Electronic Sensors Include: Resistance sensors are Resistance Temperature Devices (RTDs), and are used in measuring temperature. Voltage sensors could be used for temperature, humidity and pressure. Current sensors could be used for temperature, humidity, and pressure. The typical current range is 4 to 20 ma (milliamps).

32 Temperatures Sensors Can be either Thermocouple, RTD, or Thermistor. This Chart Compares the Advantages and Disadvantages.

33 Modern HVAC DDC Sensors Include Humidity and Temperature Transmitters CO2 for Indoor Air Quality (IAQ) Utilizing Demand Ventilation Power Meters Branch Circuit Monitors Energy Meters

34 Controllers Can Include: Electric Controls Pneumatic Controls DDC Controls Electronic Controls

35 Controllers Principles The Controller Receives the Input and Processes an Output

36 The DDC Controller Has 3 Functions 1. Receives the Input From the Sensor 2. Performs a Logic Function 3. Processes an Output

37 Basic DDC-Electronic Control System

38 Direct Digital Control System DAMPER DUCT ELECTRIC MOTOR DIGITAL COMPUTER With INTERFACE HARDWARE ELECTRIC OPERATOR SPACE VALVE PNEUMATIC OPERATOR DISCHARGE SENSORS E-P TRANSDUCER VALVE FINAL CONTROL ELEMENTS

39 Controlled Devices Dampers and Valves Automatic Control Typical Multiblade Dampers Typical Single - and Double-Seated Two-Way Valves Typical Three-Way Mixing and Diverting Valves

40 Controlled Devices 2-Way & 3-Way Control Valves

41 DDC Control Systems - Use Control Valves That Are Fully Electronic 3-Way Control Valves Not commonly used 2-Way Control Valves Used with DP sensors and VSD pump systems Pressure Independent Characterized Control Valves (PICCV) No Cv required, reduced pumping costs, higher efficiency, easy to balance

42 Controlled Devices Economizer Damper Actuators Direct Connect Actuator Damper Connected to Actuator Via Shaft and Coupling

43 Damper Actuators are Controlled by Either a Voltage (2-10vdc) or Current (4-20ma) Signal from the Controller Courtesy Belimo

44 Electronic ASDs, VFD s Adjustable Speed Drives Vary Frequency of Motor Often Called VSDs or VFDs Used with Any Variable Motor Speed Control Application

45 Adjustable Speed Drives Turn AC to DC and Back to AC (Pulsed PWM)

46 Variable Frequency Drives (VFD s) are Becoming Standard Equipment On: Towers VAV Fans Pumps Chillers

47 Example of DDC Controls

48 Example of DDC Control Heating Coil Control With Reset

49 Example of DDC Control Converter Control With Reset

50 Variable Speed Pumps are Used in HVAC Projects for Energy Conservation The Westin Building: Hydronic System VSD s match calculated Building Demand to Cooling Tower tonnage

51 VSD Drives on Fans to Maintain Static Pressure for Energy Conservation

52 Many Factory Built-Up AHU s Are VAV with DDC Controls

53 Modern Control Systems Tie All Building Systems Together Via a Standardized Networks (TCP/IP, BACnet, LON) HVAC Life Safety Systems Lighting Security Chillers Boilers Building Switchgear

54 DDC Software is Integrated into the Building Systems Current automation systems allow communications with multiple vendors Fire alarm, security Lighting, fan units PLCs (Programmable Logic Controllers) Boilers and chillers

55 BACnet Software Standard Protocol BACnet, Developed by ASHRAE True, Non-proprietary, Open Protocol (Industry Standardized) Multiple Vendor Controllers

56 BACnet Connectivity

57 Third Party Interface vs. BACNet Gateway

58 LonWorks Platform (Open Protocol)

59 LonTalk and the Neuron Chip

60 BACnet is the Preferred and Fastest Growing Network Standard Units (1000s) Revenue (mill $) BACnet Lon Pro- BACnet Lon Pro- prietary prietary * Units sold and revenue for BACnet, LonWorks, and proprietary systems in the building automation industry, (Source: Frost & Sullivan, North American Building Protocol Analysis, 2001 #A143-19)

61 DDC Networks Have Lot of Connections And Don t Always Communicate between the Various Vendors Application A Application B Application C

62 Niagara Normalizes All Systems BACNet or LON Network Application A Application B Application C

63 DDC Control Systems Schematics are done on AutoCAD Drawings are sent via As Built Modifications are easy to change

64 Example of DDC AutoCAD Boiler Controls

65 Typical DDC AutoCAD-Example Schematic Actuator Sensors Controller

66 Typical DDC Software Controls on Factory AHU s Economizer Example Sensors Controller Actuator

67 Typical DDC Software Controls on Factory AHU s Economizer Example Sensors Controller Actuator

68 Typical Controls on Factory AHU s Example of Program for Siemens Controls

69 Typical Controls on Factory AHU s- Example of Program for Siemens Controls

70 Typical DDC Controls AHU s-example of Automated Logix Graphics Display

71 Present and Future DDC Systems Are Using Smart Card Access Employee ID Card Physical Access Badge Remote Access Token Combines function into a single smart card on a USB stick

72 Present and Future Control Systems are Using PDA s by the building operators are used as diagnostic and maintenance tools.

73 Present and Future Control Systems Will Be Able to Do Anything Money Will Buy Including: Using Cloud Height Ceilometers Owners can know the weather without going outside. Performance and reliability in all weather conditions up to 25,000 feet GPS Tracking Systems on each individual in the Building 75

74 Present and Future Controls are Using Wireless Mesh Networks Wireless Networks Include: Wibree Bluetooth ZigBee

75 Present and Future Controls are Using Wireless Power Meters

76 Present and Future DDC Controls are Smart at the Field Level Telephone Thermostats Talking Thermostats Smart Air Velocity Sensors

77 Present and Future DDC Controls are Smart and on the Internet WEB

78 Present and Future DDC Building Control Systems Will Control Individual Lighting Monitor Each Tenants Total KwH Power Control RH and CO2 Provide Customers Options to Control Individual Space or Cubicle Areas via the Web

79 Present and Future DDC Control Systems Can Use Door Lock ID tags to always tell management where you are in the building. Radio frequency ID systems which allow you to track building inventory and manage information with reliability, even in harsh industrial environments.

80 DDC Challenges and Obstacles for HVAC Instructors and Students DDC Building Systems are becoming more complex. Information Tech (IT) Departments need to be involved in maintenance of building controls Future trends and demands for skilled labor is creating shortages (not enough people entering blue collar trades)

81 DDC HVAC Controls Changes and Challenges Building Controls are Evolving to become: Totally Integrated Modern Sensors and Instrumentation Devices will be Adopted Maintaining Building Efficiencies and Comfort at Minimum Costs will be more complex. Challenges and Obstacles will be a continued shortage of skilled labor.

82 Getting Started with DDC at your HVAC School Network with Industry Work as Summer Interns Develop or Buy Updated Curriculum

83 Getting Started with DDC at your HVAC School Get the DDC Equipment Donated is Ok, New is Better Start Writing Grants

84 Answers to DDC Controls Quiz T F DDC HVAC and Systems PLC s are cost basically over 35% the of same control the devices. energy in the typical building T F There minimum are 3 key CFM components requirements of any for a DDC home controls is based system. on the number of people T F BACNet, According Lon, to EPA and and Tridium WHO, are Americans Open Software DDC Integration Tools spend approximately 90% of their time 4. T F The thermistor is indoors. linear like the RTD TT F The High Boolean return air Point CO2 is above used for 1000 converting ppm is temperature an indication sensors of into IAQ useful problems. information. 10.T F Vents, chimneys, flues must be at least 10 from outside air intakes.

85 DDC Controls and Software for the HVACR Lab by Greg Jourdan Wenatchee Valley College Any Questions? Thank You 87