BMS.ppt

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Building Management System

Basics, Functions and Future Trends

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Agenda

• BASIC CONTROL SYSTEM

• Pneumatic, Electric, Electronic and DirectDigital Control.

• Direct Digital Controller Structure,Functions and Features

• Energy saving programs within the BMS • BMS Network and Open Protocols

• Facility Management and Integration

• Integration with Maintenance Manager

•

New Trends

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A ert M. Butz nvents t ethermostat

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HVAC CONTROL History

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Function of HVAC controls

A Heating, Ventilating, and Air-Conditioning (HVAC)

Control system operates the mechanical equipment

(boilers, chillers, pumps, fans, etc.) to maintain the

proper environment in a cost-effective manner. Aproper environment is described with four variables:

temperature, humidity, pressure and ventilation.

Temperature —

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Function of HVAC controls

The comfort zone for temperature is between 68°F

(20°C) and 75°F (25°C).Humidity —The comfort zone for humidity is between

20% relative humidity (RH) and 60% RH

Pressure . The rooms and buildings typically have a

slightly positive pressure to reduce outside air

infiltration.

Ventilation . Rooms typically have several complete air

changes per hour. Indoor Air Quality (IAQ) is animportant issue.

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BASIC CONTROL SYSTEM

Sensor

A sensor monitors and measures a variable. The HVAC variables are temperature,

humidity, and pressure. Different types of signals are produced by different types of

sensors.

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Controller

The controller receives the signal from the sensor and produces an output signal

with setpoint, sensitivity (differential or throttling range), and action. Types of signals from

these devices are as follows:

Electric Controls The majority of electric controls contain the sensor and controller

as one piece. Electric controls use ON / OFF signals.

Pneumatic Controls Controller outputs are 3 to 15 psi (21 to 105 kPa).Electronic Controls There are basically two types of electronic signals.

Voltage outputs may be 0 to 10 Vdc, 2 to 15 Vdc, or other ranges depending on the

controller. Voltage outputs have the disadvantage, when compared to current signals,

that voltage signals are more susceptible to distortion over long wire distances.

Current outputs modulate from 4 to 20 mA. They have the advantage of producing

little signal distortion over long wire distances.

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Compressed air from compressor is used to as a source of energy for Pneumatic

Controllers. E ach Pneumatic controller support one control Loop. Currently is Used

for specific applications and service cost is expensive.

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Electric Controller handles one control function, usually support ON/OFF Control

Mode (Fully open or fully closed final control element). Also is slow and rarely used

now.

Electronic Controller handles one control function, and support either modulating or

ON/OFF Control Mode. Used for small jobs as economic solution.

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Centralizing Control WithMimic Panel

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Direct Digital Controllers(DDCs)

Direct Digital Controllers is a microprocessor based device, and has a battery backed

memory to hold control programs and operating system, and also Input / Output

connectors to deal with sensors and final control elements.Direct Digital Controllers are the core product for the Building Management System.

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Some Direct Digital Controllers already have built in program and called Unitary

controllers and handle the control of specific equipment (Simple AHU, Fan Coil,

VAV,..ect). Programmable controllers support multiple applications and equipment.

Direct digital controllers can handle more than control loop at a time.

slide 16

maths

logic

PID

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Graphical programming tool is usually used to program and configure DDC

controllers.

Each manufacturer implement the proper programming language for his own

product. slide 17

i i i l ll

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Direct Digital ControllersInput/ Outputs

Different Type of inputs and outputs are connected to the DDC controller.

slide 18

Analogue

Temp

Pressure

Humidity

DigitalRunFault

Trip

Analogue

Modulated

DigitalOnOn

On/OffPulse

Meters

maths

logic

PID

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Direct Digital ControllersInput/ Outputs Example

slide 19

Digital Inputs Examples:-Differential Pressure Switch is an example of Digital Input.

Usually installed across a fan or a filter. If the contact is

closed the DDC can detect either the fan is running or the

filter is clogged.

Smoke Detector installed in the duct to allow the controller

to stop the Air Handling Unit in case of Fire.

Auxiliary contact from contactor to indicate if the contactor is

energized or NOT.

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slide 20

Analog Inputs Example:-Temperature Sensors/ Setpoint Modules for Rooms.Temperature Sensors for Ducts.

Immersion temperature Sensors for water Pipes.

Humidity Transmitters for Rooms and Ducts.

Differential Pressure Transmitters for Clean

Rooms.

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slide 21

Analog Output Examples:-DDC produce a voltage signal ranged from 0 to 10 Volt.

According to the value the controlled device respond.

To Control the Fan Speed via inverter (Speed Drive).

To Modulate water Valve .

To Modulate Damper Motor and control Air

Flow.

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slide 22

Digital Output Examples:-Digital output is a relay output controlled by DDC

To Energize contactor in the motor control center in order to

start Fan or Pump.

To Start a condensing unit when using DX Air

Handling Units.

To energize Heater Battery Stages via

contactors

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slide 23

DP

T

DP

T

DP

T

T

DP T

T

T

DP

boilers

DP

T

DP

T

DP

T

T

DP T

T

T

DP

chillers

FST T

T

air handling units

Application Programs

After connecting Field devices via Input/

outputs module, the application programs can

be downloaded to the controller memory

(Usually by using Laptop computer).

Commissioning and testing stage will start

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slide 24

DP

T

DP

T

DP

T

T

DP T

T

T

DP

boilers

DP

T

DP

T

DP

T

T

DP T

T

T

DP

chillers

FST T

T

air handling units

Application Programs

After connecting Field devices via Input/

outputs module, the application programs can

be downloaded to the controller memory

(Usually by using Laptop computer).

Commissioning and testing stage will start

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slide 25

Programming Tool

Programming Tool consists of mathematical and Boolean modules that

are connected to the inputs and outputs and also to each other in orderto produce the HVAC control Applications

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slide 26

Application Program

After Finalizing the application program, It is tested off line and then

download to the controller.

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slide 27

PID Module

The most important module is the PID that is usually used to drive an

analog signal for the final control element (Motorized Valve or Damper

actuator) in order to get the controlled medium to setpoint

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PID Control

The PID Module calculates the errorbetween setpoint and measured value and

apply a control algorithm that is based on a

proportional gain, an integration action and

a derivative action.

Proportional Action Proportional Plus

Integral Actions

Proportional Plus

Integral Plus

Derivative Actions

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PID Control

With proportional control, the output is a function of thedeviation of the controlled variable from the setpoint. As

the control point stabilizes, offset occurs.

Proportional

Action

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PID Control

With the addition of integral control, thecontrol point returns to setpoint over a

period of time with some degree of

overshoot.

Proportional Plus

Integral Actions

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PID Control

The significant difference is the eliminationof offset after the system has stabilized.

The adding the derivative

element reduces overshoot and decreases

response time.

Proportional Plus

Integral Plus

Derivative Actions

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Energy Management

Hemisphere)

Energy Management Programs are Built in the

Direct Digital Controllers memory and help in

saving power in case of the proper FieldDevices are installed.

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Energy Management Comfort Costs

Energy Management is a compromise

between comfort and cost. It works between

the extreme boundaries of temperature and

RH.

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Hemisphere)

• Night cycle

• Optimum Start/Stop

• Zero energy band

• Load reset

• Night cooling• Enthalpy control

• CO2 control

• Peak shaving

• Duty cycling• Presence detection

• Lighting control

Energy ManagementThe Most Applicable Energy Saving

Programs.

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Optimum Start Stop with cooling

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Optimum Start Stop with cooling Optimum period to start and stop

HVAC Equipment while comfort

weather is reached during

occupancy.OccupancyOptimumStart

OptimumStop

R o o

m t e

m p e r a t u r e

s e t p o i n t

NightNight

Time

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Zero energy band

Night offset

Zero energy band

R o o m t e

m p e r a t u r e

Room temperaturesetpoint

When space temperature located

within comfort range, No cooling or

heating will be used.

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Night cooling

Ti

RHi

Ta

RHa

If

Ta < Ti &

RHa < RHi

&Time between 04:00 and 08:00

Then

Night cooling

End

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Enthalpy control

T

M

M

M

+

M

-

M M

RHT RH

T RH

Comparing outside and return

Enthalpy

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CO2 control

+

M

xy

CO2

w

DSPL

Applicable when Electrical cost is

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Time

E l e c t r i c a l

l o a d

Peak

limit

Schedded loads

higher at peak time

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Presence detection

Night offset

Standby offset

Zero energy band

R o o m t e

m p e r a t u r e

Room temperaturesetpoint

Needs Occupancy Detector

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Direct Digital Controller can work in

standalone bases. Readings can be

collected in the field by using

handheld operator terminal.

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Co

%RH

T

°C Effective Setpoint

%%

°C°C

If the direct digital controllers are connected together and

to a central computer, then the building managementsystem is established.

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The building management system software in

the computer does not perform any control

functions, as all the control routines are

executed in the DDCs.

The Building Management system function is

as follows:-.•Centralized the operation of the HVAC system

instead to pass by every machine to operate

and get the readings or change the setpoint

•Receive and record Alarms, Logs and reports.

•Low Level Integration with other systems.

•Graphic Display for equipment and readings.

S l f B ildi M t

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Sample of Building Management

Graphical Presentation

Air Handling Display

S l f B ildi M t

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Chillier Plant Display

S l f B ildi M t

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CHARTS

S l f B ildi M t

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Alarm Logs

Language of Communication

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(Protocol)


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Open Protocol

Years after, the implementation of a common

communication language “Protocol” started and

the most common protocols now are the Bacnet and

Lonworks.

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Open Protocol

The BACnet History

• 1987

The ASHRAE (American Society of Heating Refrigeration and

Air-Conditioning Engineering) Standard Project Committee SPC135P was founded. The committee was challenged to define a

communication protocol for building control and energy

management.

• January 1989 The ASHRAE journal publishes a first article about the idea of a

new protocol and the philosophy behind it.

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Open Protocol

The BACnet History• August 1991

The BACnet protocol has been sent out for a first review

• March 1994

The BACnet protocol has been published for a second reviewcycle

• Spring 1995

The BACnet protocol received a third public review.

Each of the reviews lasted for 3 - 6 month. More than 790

review comments had been collected during the three public

review cycles.

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Open Protocol

The BACnet History• September 1995

The ASHRAE Board of directors voted to ratify the BACnet

standard and published ASHRAE 135-1995.

• December 1995 BACnet was adopted by the ANSI (American National Standards

Institute) as the ASHRAE/ANSI Standard 135-1995.

• February 1996

BACnet debuted at the occasion of the International Air-Conditioning, Heating and Refrigerating Exposition.

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Open Protocol

The BACnet History• Spring 1997

The CEN Technical Committee (TC) 247 Working Group (WG) 4

adopted and published BACnet as European Prenorm ENV

1805-1 (Management Level) andprENV 13321 (Automation Level).

In the meantime BACnet also had been ratified as

DIN V ENV 1805-1.

• December 1998

The ENV 13321 "Data communication for HVAC application:

automation net" became approved.

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• BACnet is a communication protocol to exchange data

in Multi-Vendor Building Management

Systems/Networks

• It fits to the requirements of heating, cooling,

ventilation control but ...

• may also be the basis for integration of applications

like lighting, security and fire control

What’s BACnet good for?

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• The sophistication of a specific device, in terms of itsability to carry out particular service requests is

reflected by the device's conformance class.

– Each conformance class specifies a minimum set of services,

objects, and properties which the device must support inorder to claim membership in a particular class.

• The terms initiate and execute are used to describe a

device's capability to perform the application services

defined in the standard.

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• Functional groups: collections of BACnet standardobject types and application services that collectively

meet the communication requirements of a single

building function.

– The idea is to support specifiers as they specify specific

functionality like Event Initiation or Clock for particular

devices.

• BACnet is compliant to the OSI Communication

Model.There are various options for the physical and

the datalink layer.

What is the BTL?

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What is the BTL?

BACnet Testing Laboratory was established by BACnet

International to support compliance testing and interoperability

testing activities.

General activities of the BTLThe general activities of the BTL are to publish an Implementation

Guidelines document for users of BACnet® with the help of the

working group, to organize and run the annual Interoperability

Workshop, and to test products for certification.

http://www.bacnetinternational.org/btl/files/BTL%20Implementers%20Guide-17.final.pdf




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LONWORK BY

•Founded By Mike Markkula (Intel,Apple)

•Over 450 Products in product range

•Head Office: Palo Alto, California, USA.

•Over $100m and 500 man-years invested in bringingLONWORKS Technology to the market place

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LONWORK BY

• Device Interoperability

• Intelligent Devices

• Standard Point Types (SNVT’s)

• Manufacturer Independent

• Open Communication Protocol (LNS)

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Lonmark

• Independent Organisation

•The LonMark logo is an indication that a

product completed the LonMark conformance

tests and has been designed to interoperate across

an open multi-vendor LONWORKS control network

• More than 200 members

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Neuron Chip• Most LonMark devices have this micro chip inside

• Designed by Echelon

• Made by Motorola, Toshiba & Cypress Semiconductor• Every chip has a unique 48 bit ID

• There are different Neuron chips for different uses

with the same design but different memory size, CPUspeed etc...

This keeps the price down for smaller devices but the

processing power for complex devices

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Neuron Chip

I/O (Counters

Resources

Drivers, etc..)

Application

CPURAM/ROM/EPROM

Media

Access CPURAM/ROM/EPROM

Network

CPURAM/ROM/EPROM

Protocol Firmware

(Layers 1-2)

Protocol Firmware

(Layers 3-6)

Transceiver

Optional

External

Memory

I/O

Conditioning

Power

Regulator

Node Specific

ProgramNeuron ChipID #65673882930482726987...

Network

Comm

Port

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Neuron ID• Every device has a unique Neuron ID stored in the chip

at manufacture, this cannot be changed.

• When a device is commissioned the Neuron ID isrequired to make sure the correct device is programmed.

• There are Three methods of acquiring the Neuron ID

1. Manual Entry- Type the ID into the tool or Use a barcode reader.

2. Discovery- the network tool can discover unconfigured

devices

4. Service PIN- press the devices service pin

Protoco D erences on Pro ucts

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and Services

LONBacnet

Future Trends

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Future TrendsCustomer Expectations

• Reduction of initial investments

• Building Control System uses existing IT infrastructure

• A single user interface for all building disciplines (HVAC, Lighting, Lifts,Fire, …)

• Customers want supplier independence in case of later systemenhancement

• Reduction of operating, energy and maintenance costs

• Mobile operators want to operate the building at any time, fromeverywhere, immediately

• Less trained operator needs “intuitive" operating interfaces

• Central “Help Desk” serves many buildings in a geographical region

• Growing expectations for comfort and service

• Reduced energy consumption

Future Trends

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•Global connectivity

• Global companies need global BMSinformation

•Easy to operate

• Access at any time, from everywhere,immediately

• Use mainstream technology

• IT-world compliance

• Slim, inexpensive clients

Future Trends

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