UNIVERSITY OF NUEVA CACERES COLLEGE OF ENGINEERING AND ARCHITECTURE

5: Building Management Systems (BMS)

I. Introduction
Modern establishments are integrated with systems providing necessary services for comfort,
efficiency, security and safety. All these systems are applied regardless of what field a building is used for.
Some of these systems are now a general requirement especially for establishments for public use,
primarily to ensure safety.

Building management systems are generally mechanical and electrical in nature. For many years,
it is operated manually until the introduction of sensors and transducers, wireless communications and
networking. Nowadays, all these systems are centralized and can be controlled from a single point, remote
even. This module will tackle on what is the function of building management systems and what it is
composed of.

II. Objectives
After completion of the course the student should be able to:

1. Differentiate the different Management Systems employed on building establishments.

2. Describe the implementation of HVAC system and the parameters to consider.
3.

III. BMS Basics

BMS is a system that centrally monitors and controls the building technical systems and services
for the purpose of automation, safety, information and efficiency. Some of these systems may provide
corrective actions before and after an event occurs. It is also known as Building Automation System (BAS),
Building Management and Control System (BMCS), Direct Digital Control (DDC) and Building Controls.

This generally includes the following systems:

 Heating, Ventilation, and Air Conditioning (HVAC) System

 Lighting System
 Fire Detection and Alarm System (FDAS)
 Security and Surveillance System
 Background Music and Public Address (BGM/PA)
 Access Control System
 Water System
 Elevators and Escalators

BMS is not really necessary to operate a building especially that these systems come with a great
cost, but a BMS-equipped establishment surely provide a great deal of advantages far-weighing the cost
of implementation. Here are some of the advantages of applying BMS:

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 Security and Safety. Buildings are primarily designed to be occupied. People must be ensured of
their security and safety while living or working within the confines of the building. BMS oversee
the auxiliary systems for security and surveillance as well as the utilities in case of emergencies.

 Centralization. A BMS allows the management of several auxiliary systems in a single station
where the entire building operation can easily be monitored. Most of the issues is addressed even
before the occupants notice it. Some companies may have multiple locations for their
establishment and with BMS, they can oversee the events occurring in each location.

 Energy Savings. Operations in a building consumes a lot of power. Machines turn on and off all
the time. With the help of building automation, substantial amount of energy can be saved.
Sensors are normally used around the building to monitor and detect events; it helps in controlling
equipment operation in the most efficient way.

 Financial Savings. BMS is actually designed to save money by optimizing the operations within
the building and increasing the efficiency of equipment. With monitoring, systems are maintained
based on schedule. All of these results to a lesser operational cost of the establishment.

Source: Slideshare

Figure 5.1. BMS

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Current BMS are designed with open communications protocol to allow integration with
other architecture. It also supports Web integration so it can be accessed through the internet.
The most common application of BMS is the HVAC system where provides management of air
conditioners, fans, chillers, pumps, boilers, etc.

BMS Components

Hardware. Composes the physical components of the BMS. It is subdivided into three:

 Computer and HMI Display – the workstation used for everyday building operation. It
comes with a powerful software that oversees the entire system. It also contains the
database that log every event. It is where the user monitors the system and perform
control actions. Human-machine interface (HMI) displays usually are touch-screen
devices that allows a user to interact with the machine.

 Controllers – are microprocessor based programmable devices that generally control a

system such as HVAC.

 Field Devices – refers to the devices directly used to measure or vary the parameters being
monitored by the system. Commonly include sensors and actuators.

Source: FMA

(a) (c)

(b)

Figure 5.2. (a) Computer and HMI display,

(b) DDC controllers, (c) Field Devices

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Software. Composed of the computer applications that usually comes with the BMS system which
is capable of programming and configuration of the hardware components. It also includes
features than can visualize the current parameters of the process.

Source: FMA

Figure 5.3. GUI Examples of BMS

Application Software

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Network. Refers on how the components

are connected and able to communicate. It
includes several protocols and open
standards that governs the transmission of
data between the BMS devices. Figure 5.4
shows the integration of different systems
remotely operated using TCP/IP.

Some commonly used protocols

include:

o DeviceNet
o SOAP
o XML
o BACnet
o LonWorks
o ModBus
o ZigBee

Figure 5.4. System Integration

The architecture of the BMS system is arranged according to hierarchy as shown in Figure
5.5a. The function of each level is briefly illustrated on Figure 5.5b.

Source: Youssef
Operation and
Management Level

Automation and
Processing Level

Field Devices Level

(a)

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Source: Honeywell
(b)

Figure 5.5. (a) BMS Architecture, (b) BMS Level functions

BMS Features

 Human-Machine Interface (HMI). Human operators can interact with the building
equipment. End-user BMS devices are designed user-friendly so they can easily be operated
by personnel assigned to them.

 System Security. Computer workstations and HMI devices are the primary device that can
control the machines so it must be secured from unauthorized use. Such devices are usually
password protected and logging access are summarized.

 Data Presentation. Provides the graphical representation of the building and floor plan
showing an organized flow of information from the equipment processes.

 Data Logging. Data are automatically gathered and stored for later analysis and report.

 Data Analysis. Data from the field devices are collected and presented as output for easy
analysis of information. It may be presented in charts and graphs.

 Remote Connectivity. System can be accessed remotely with full functionality using a local
network and internet.

 Alarm Management. Machines normally encounter errors. Alarms – whether visual or aural
– are used to indicate a potentially dangerous situation or deviations from expected value. It
informs the operator to take appropriate actions.

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 Time Scheduling. The start and end of equipment operation can be scheduled. This saves
energy cost and provides a more efficient operation. This is particularly effective with lighting
system and occupancy control.

 Event Recording. Provides automatic logging of operator activities and commands and events
like errors encountered by the system.

IV. Heating, Ventilation and Air Conditioning (HVAC) System

The primary function of HVAC system is to provide a comfortable indoor condition for the
occupants of the building. It basically refers to the air system of the building that regulates the
temperature, humidity and improves the quality of air. Air quality is an essential consideration in
maintaining the productivity, comfort and health of the occupants. If the quality of air and temperature
is not properly maintained, it has a direct consequence on the occupants. Figure 5.6 shows the simple
block diagram of an HVAC system.

Source: Google
Figure 5.6. HVAC Block Diagram

Objectives of HVAC System

In designing an HVAC system, it must perform the following objectives:

 Controls Temperature. The HVAC system must be capable of adjusting the temperature within
the enclosed space, to provide a comfortable environment for the occupants.

 Fresh Air Circulation. The HVAC system must be capable of supplying fresh air for the occupants
to experience better health and performance gains for whatever work they are into. Air circulation
alleviates the build-up of carbon dioxide within the room.

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 Air Filtration. In an air-conditioned facility, the circulation of air carry contaminants that
contribute to respiratory illness. The HVAC system must be capable of removing these
contaminants and dusts using filters at different stages of circulation. This is more necessary for
establishments utilizing clean rooms for a manufacturing process or proving medical services.

 Efficiency. With the increasing cost of fuel and power, HVAC systems must be cost and energy
efficient with a relatively low operational cost. It is important to design and implement an HVAC
system that corresponds to the needs of the building.

 Unobtrusive and Quiet. The HVAC system must operate in an unobtrusive manner to provide a
pleasant environment for the occupants. Noise coming from a poorly installed HVAC component
will interfere and affect the morale of the occupants.

Air Conditioner
Air conditioning is the process of altering the properties of air to provide more
comfortable indoor environment. Its processes usually include cooling, heating, and
dehumidifying. There are several types of air conditioning system and it choosing the appropriate
type usually depends on how large the area is to be cooled.

Window-type Air Conditioner – the most

commonly used air conditioner for a single room. It is
composed of a compressor, condenser, expansion
valve, evaporator. All these components are compacted
in a box assembly. It is usually installed in a slot made on
the wall like a window.

(a)

Split-type Air Conditioner – similar to the window-type,

it is used for single room but is usually suited for large-sized
spaces. It is a system composed of two parts – outdoor and
indoor unit. The outdoor unit is comprised of the compressor,
condenser and expansion valve, while the indoor unit is
comprised of the evaporator and fan.

(b)

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Floor Standing Air Conditioner – suited for

two or more rooms or a large space such as an office.
It is packaged in two different ways: all components
are housed in a single box or it has an outdoor unit
similar to the split-type air conditioner. It has a high-
powered blower that pushes the air across the office
or various rooms.

(c)

Centralized Air Conditioner – implemented for large

houses and buildings such as hotels, malls, theaters, etc.
This is more reasonable to implement instead of placing
stand-alone units in every room. It is generally known as
HVAC system.

(d) Figure 5.7. Types of Air Conditioners: (a) Window-type, (b)

Split-type, (c) Floor standing type, (d) Centralized

HVAC Components

Air Handling Unit (AHU)

A central air conditioner station that

handles the air that is supplied into the
building via ventilation ducts. It contains
Source: Google

blower, heating and cooling elements, air

filters, and humidity and temperature
control loops.
The air handler contains a fan or
blower that pushes the air throughout the
Figure 5.5. AHU
building’s ventilation ducts. There are two major
types of fan used – Axial Fans and Centrifugal Fans.

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 Axial Fans operates similarly to an airplane propeller in which

blades arrangement produces pressure to move to the air. It is
commonly utilized by most industries due to its cheaper cost,
compactness, and lightweight. However, axial fans are naturally
loud and produce greater vibrations which are then transmitted to
the metal-made ventilation ducts.

 Centrifugal Fans are radially designed to produce higher air (a)

pressure making them suitable for environments with harsh
operating conditions like a warehouse or a parking lot. The blades

Source: PTI
are fabricated to curve forward or backward.

o Forward-curved Centrifugal Fans create more air pressure

– reason why it is also called blowers. It durable and easy
to maintain however they tend to produce loud noise and
requires more power to operate.
o Backward-curved Centrifugal Fans are excellent for high
volumes of airflow and variable air resistance. It is often
used for industrial purposes. (b)

Figure 5.6. (a) Axial Fan,

(b) Centrifugal Fan

Chiller / Air-conditioning Unit

An equipment that produce cooled liquid by

removing heat from a liquid through vapor compression
or absorption refrigeration cycle. This liquid flows through
the building pipes, passing through coils in AHU, fan-coil
units, and usually dehumidifying the air in the building.
Figure 5. shows the components of a chiller.

There are two types of chillers – Air-cooled chiller Source: Carrier

and Water-cooled chiller. The differentiating feature
between the two types is the method used to condense
the refrigerant as it leaves the compressor, as described
by the terms used.

Air-cooled chiller has lower installation and

maintenance cost, easily available for installation, no Figure 5.5. Chiller Components
cooling tower or condenser pumps needed, and does
not require a mechanical room. While Water-cooled chiller is costly and usually custom-made
because of its size but it provides more efficiency and it lasts longer than the other. It is usually
installed indoors.

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Source: Google
(a) (b)

Figure 5.5. (a) Air-cooled Chiller, (b) Water-cooled Chiller

Cooling Tower

This equipment accepts the warm water by-product of the

chiller and cools it by contacting with unsaturated air. This
causes evaporation that mainly provides cooling.

Figure 5.6. Cooling Tower

Air Filters

The air filter extracts impurities from the air passing into the device, such as pollen, pet dander or
even bacteria. This not only increases the air quality in your house, but also protects against
damage to your HVAC system. There are different kinds of air filters for HVAC:

 Flat-panel Filter. These are standard flat-panel models and the most economical type of air
filter, have fibers spread over a substrate, most often fiberglass. They are reversible and
simple to mount, but they are not always of the best quality, enabling the passage of several
objects. It performs better protecting the air conditioning system than screening dust and
toxins in the air. You could also be vulnerable to breathing issues if you use this sort of air
filter.

 Pleated Filter. In order to eliminate contaminants from the air, disposable pleated filters use
thick screens of cotton or plastic fibers. They have pleats, which have more surface area for
filtration and allow the filter to collect more particles, unlike their flat-panel equivalents.

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 Electrostatic Filter. In order to capture more (and smaller) particles like pollen, smoke or
bacteria in their windows, these filters are electrostatically charged. They can be smooth or
pleated, and can be washable or disposable.

 Washable Filter. To eliminate any particle buildup, reusable filters can be washed with water
or vacuumed. They are eco-friendlier than filters that are removable. Washable air filters cost
more than disposable forms, but in the long run, they save you a great deal of cost. They can
be replaced and washed, so you do not need to replace them regularly.

 High-Efficiency Particulate Air (HEPA) Filter. Refers to any filter that eliminates at least
99.97% of particles 0.3 microns or larger in the air. While they are most commonly used in
commercial environments such as hospitals and laboratories that require exceptionally clean
air, they can be used in homes where individuals suffer from allergies or have a compromised
immune system.

 Ultra-violet (UV) Filter. Ultraviolet lights are used to kill bacteria and viruses in your home.
They are good at combating microorganisms that are also dangerous to your health, although
less effective in screening dust and other pollutants.

Source: Google
Figure 5.7. HVAC Filters

Ductwork

Ductwork refers to the duct system made of metal or synthetic tubes which are installed all over
you’re the building to move air from the HVAC equipment. A core component of the quality of
indoor air and home comfort are well built and well-maintained air ducts. These ducts are
fabricated round, square or rectangular and commonly made of galvanized steel, aluminum,
polyurethane and phenolic panels, or fiberglass.

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Figure 5.8. Ductwork

Source: Google
Dampers

Dampers are mechanical devices in a duct that regulates airflow. It is located in the ductwork near
the AHU, that regulates airflow and redirects it to specific areas of the home. A damper contains
a movable plate that provides simple mechanisms that can close parts of the duct system.
Generally, dampers have two types – Manual Dampers and Automated Dampers.

Along the ducts, there are Terminal Units that uses automated dampers to regulate the air
delivered to a particular region in the building. The damping mechanism is controlled electrically
or by a pneumatic or digital system, which is then regulated by a thermostat.

Figure 5.9. Duct Dampers

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Heating Coils

These components are installed in the Air Handling Unit (AHU) to provide heat. Heating coils may
also be installed after a terminal unit to provide heat for a specific region of the building.

Figure 5.10. Heating Coils

Source: Google
Linings and Attenuators

Linings are used to dampen the noise within the duct which is generally caused by the air flow
through the duct and vibrations from the fans. Attenuators are short-length ductwork with linings
often installed after a terminal unit to dampen discharge noise.

Figure 5.11. Lining and Attenuators

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Grilles / Registers / Diffusers (GRDs)

Devices used cover a vent and intake or deliver the conditioned air to a room or space in a
building. GRDs are properly designed to control the flow rate, direction and balance the
distribution of air within an enclosed space. The following states the differences between these
devices.

 Grilles. Any vent cover that are used as air outlet or intake
from an enclosed space. Grilles are the simplest among
these devices having no moving components or dampers.
It has no control the direction of airflow.

(a)

 Registers. The register is the same as a grille, except there

are adjustable dampers in it. Unlike grilles, registers are

Source: Google
used only as an air outlet that feeds air into indoor spaces.
Similar to the adjustable vents of a car's aircon outlet, the
dampers help to control the airflow direction or to shut off
the flow.

(b)

 Diffusers. A diffuser allows the air to flow in various

directions. It has dampers designed to face the all-round
way, rather than the single air direction of a register. Most
diffusers are located on the ceilings where it disperses the
air uniformly across a space or in specific paths at once.
The pattern and the airflow direction, however, depend on
the design and position of the dampers.

(c)

Figure 5.12. (a) Grille, (b) Register,

(c) Diffuser

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HVAC Zoning
The entire building is divided in to regions called Zones. A zone may be a single room or a
set of adjacent rooms which have identical heating and air conditioning needs.

Source: ABE Heating and Cooling

Figure 5.13. HVAC Zoning

Typically, one terminal unit with corresponding thermostat is assigned to each zone. In
some implementations, the thermostat in a zone is accessible to occupants so they can adjust the
temperature based on their needs.

V. Video References
Here are some videos to aid your understanding about BMS and HVAC Systems:

Title Link
What is Building Automation Systems https://www.youtube.com/watch?v=OeVt4_5GLxQ
Building Automation Systems (BAS)
https://www.youtube.com/watch?v=nMylWwzzo0k
Architecture
Building Automation Systems (BAS)
https://www.youtube.com/watch?v=ByrysZAwoPI
Operations

Fundamentals of HVAC - Basics of HVAC https://www.youtube.com/watch?v=fqvo7bSr6t8&t=31s

Fundamentals of HVAC - Comfort Criteria https://www.youtube.com/watch?v=qZ3RwH018Qw

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