HVAC Fundamentals

Fundamentals of HVAC Systems is a thorough introduction on how HVAC systems control temperature, air quality and air circulation in a conditioned space.
Ideal for recent engineering graduates working in the HVAC&R industry, experienced engineers entering HVAC&R from another engineering area, as well as architects, technicians, construction or building management professionals who need to increase their knowledge of HVAC systems.
This course reader can function as a stand-alone reference, or may accompany the eLearning course, Fundamentals of HVAC Systems, online modules.

1. HVAC
Fundamentals
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2. Objectives
•Basic industry terms
•Basics of BMS and HVAC
To gain familiarity with:
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3. Why have Controls and BMS ?
Safety
• of People
• of equipment
Economy
• Save money
• Use just the right amount of
energy (electric power, gas
etc.)
• Increase equipment life by
using it efficiently
• Protect equipment and
products (avoids wastage -
paintings in a gallery,
drug/chemical stores)
• People’s productivity
Comfort
• Too hot/cold
• Too dry/humid
• Too polluted
• “Sick Occupancy”
• Health and Safety
• 21 Deg C/ 50% RH
•24 Deg C/ 50% RH
• Enough Fresh Air
• Clean Air
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4. Why have Controls and BMS ?
Comfort
• Need to ADD/REMOVE heat and/or moisture
• Need to clean (filter air) and supply adequate fresh air
People lose heat (feel cold) - amount they lose depends on temperature
around them - cooler it is, more heat they will lose through their skin
OR they “generate” heat (feel warm/hot - WORK TOO HARD!) - need to
cool them down by reducing air temperature around them
People feel “muggy” - the air around them has too much moisture
People feel “dry” - not enough moisture in the air around them
Buildings (where people live and work) also lose or gain heat (through walls,
Windows, floors, roofs, heat generating equipment e.g. VDUs, and
computer equipment)
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5. Why have Controls and BMS ?
Safety
• Need to provide protection against equipment running “wild” / out of control
• Need to make sure people are safe at all times
Can’t have coolers or heaters (boilers) running “wild” - they might
freeze up or blow up!
If too hot or cold for long period of time - affects their health
Sometimes you have special needs for process (making capsules,
fiber, etc)
Hospitals may have special needs for patients / medicines / labs
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6. Why have Controls and BMS ?
Economy
• Use energy efficiently - use plant efficiently - make people comfortable
(they will produce more???)
Electric power or fuel (gas, coal, oil) is expensive and limited (?)- need to use
efficiently
Environmental issues (Clean atmosphere for the occupants)
Need to ensure maximum return on investment - prolong equipment life and get
the best out of it
Increase productivity of people increased profits for offices, hotels, etc.
Ensure that products you are making/ supplying (e.g. supermarket) do not
deteriorate because of bad “environment”
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7. •How do you heat / cool your
home?
•How does the heating /
cooling know when to turn
on?
•How does the Hot / Chilled
water turn on and off ?
You already know Controls.....
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8. •What does the thermostat
do?
•What does the A/C do?
•What does a radiator do?
•.. and the time switch?
In your home
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9. •Larger areas to be heated or cooled therefore bigger
equipment
(e.g. Chillers, pumps, valves)
•Different types heating/cooling equipment are used.
•Operational needs are different e.g.
•different areas of the buildings occupied at different times
•different areas have differing heating/ cooling requirements
•Central monitoring point for Building Energy Management
System
Air-conditioning in large buildings
Basic issues are same - Comfort, Safety, Economy, BUT
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10. •People working in the industry refer to Wet and Dry
Systems in a building
Wet & Dry Systems?
Wet Systems:
•Any systems to do with water e.g.
–Chillers (cool Water)
–Boilers (heat water)
–Pumps (makes water flow in
pipes)
–Valves (regulates amount of
water flow through heating or
cooling “radiators” or coils
Dry Systems:
•Any systems to do with Air e.g.
–Fans (makes air flow in ducts)
–Filters (clean air)
–Dampers (regulates amount of
Air flow through the ducts)
–Air handling units (cools,
heats, filters air - ALL IN
ONE)
Need to CONTROL and/or MONITOR both Systems
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11. •Control and Monitor
•Room (Air) temperature, humidity, ventilation
•Chillers (chilled/cold water services)
•Boilers (Hot water services)
•Pumps
•Fans
•Lights
•Flow
Managing large building?
•What types of buildings and facilities do you think can use
controls and BMS?
–Any building
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12. Introduce HVAC?
HeatingHeating
Increase or
Decrease the
water or Air
Temperature
Increase or
Decrease the
water or Air
Temperature
Boilers
Radiators
Pumps
Boilers
Radiators
Pumps
VentilatingVentilating
Supply right
amount of
Clean fresh air
Supply right
amount of
Clean fresh air
Fans
Air Ducts(?)
Dampers(?)
Fans
Air Ducts(?)
Dampers(?)
Air ConditioningAir Conditioning
ALL IN ONE - HANDLES ALLALL IN ONE - HANDLES ALL
Cool AirCool Air
Heat AirHeat Air
Clean AirClean Air
Add MoistureAdd Moisture
Remove MoistureRemove Moisture
Move airMove air
Recover wasted HeatRecover wasted Heat
Air
Handling
Unit
(AHU)
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13. HVAC System in a Building
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14. Basic of Refrigeration
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15. Refrigeration
is
COOLCOOL
How it Works
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16. THERETHERE
IS NO COOLIS NO COOL
ONLY ONLY HEATHEAT
AS LONG AS THERE’S ATOMIC MOTION AS LONG AS THERE’S ATOMIC MOTION
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17. Cold can’t
be given to an object.
Heat must be removed.
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18. A Refrigeration System is a
Heat Moving Machine
Condenser
Evaporator
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19. Typical Refrigeration System
Low Pressure Vapor
Low Pressure Liquid
High Pressure Liquid
High Pressure Vapor
Legend
Liquid Refrigerant
Receiver
Evaporator
Condenser
Compressor
TX Valve
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20. Air Handling Unit
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21. Air Handling Unit
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22. Fan Coil Unit (FCU)
Room Units
Variable Air Volume (VAV) box
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23. Packaged Units
Complete Room A/C Units
Split Air Conditioning Units
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24. HVAC Air Systems
•HVAC air systems are made up of:
•AHU - Air handling units
•Dampers
•Coils and Valves
•Fans
•Distribution ducts and terminal boxes
•Pumps and Plumbing
•Control devices and control loops
•Unitary equipment: fan coils, perimeter
radiation, unit ventilators, unit heaters,
etc.
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25. AHU - Components & Terminology
RAEA
OA
Return From
Space
Filter
Cooling Coil
Heating
DA
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26. AHU components
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27. What are Functions of AHU ?
•Function:
•Condition the air
•Heat the air
•Cool the air
•Dehumidify the air
•Humidify the air
•Clean the air
•Distribute the conditioned air into the
building space.
•Commercial air handling units can be
compared to home furnaces.
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28. Air Handler Components
The damper section :
•Manually Operated for
Outside Air/Exhaust Air
•Motorized Modulating
•Motorized On/Off
•Fire Dampers – Motorized /
Fuse Link Operated

29. Air Handler Components
The fan section with
access door open.

30. Air Handler Components
Filters :
Types of Air Filters
 Pre Filters
 Fine Filters
 HEPA Filters
 ULPA Filters (Ultra Low
Penetration Air)

31. Air Handler Components
• 70-80-% Efficiency .
• Can filter particles

of size upto 5-10
microns.
• Reusable & Washable
PRE-Filters

32. Air Handler Components
•90-95 % Efficiency .
• Can filter particles of
size upto 1 to 2 microns.
• Not Reusable
Fine Filters

33. Air Handler Components
• 99.97-% to 99.99995 %
Efficiency .
• Can filter particles of
size upto 0.1 to 0.3
microns.
• Used in Clean Room
Applications.
•Not Reusable
High Efficiency Particulate Air Filters (HEPA)

34. Air Handler Components
The filter section.
Notice the cross stacking
of the filters to increase
surface area.

35. Air Handler Components
Temperature Sensor:
•Temperature sensors are used for
measurement of temperature of a
Room, Air Duct, Hot /Cold Water,
Outside Air etc.
•Models are available with PT1000,
NTC20K, BALCO500 sensing
elements.
LF20 : AIR DUCT TEMP. SENSOR (NTC 20k)
T7412 : ROOM TEMP. SENSOR (PT1000/NTC 20k)
T7413A : IMMERSION TEMP. SENSOR (PT1000)

36. Air Handler Components
Relative Humidity Sensor:
•Relative Humidity sensors are used
for measurement of Relative
humidity of a Room, Air Duct,
Outside Air etc.
•Sensor Type : Capacitance
•Combined Relative Humidity and
Temperature Sensors are available
with PT1000, NTC20K, BALCO500
sensing elements.
H7015 : DUCT RELATIVE HUMIDITY SENSOR
H7012 : ROOM RELATIVE HUMIDITY SENSOR

37. Air Handler Components
Differential Pressure
Switch:
•Differential Pressure switches are
used for monitoring of Filter, Fan,
Pump, Fire Damper, Water Flow,
Air Flow Status of air handling
systems.
DPS1000 : AIR DIFFERENTIAL PRESSURE SWITCH
TDIAP SERIS : AIR FLOW SWITCH

38. Air Handler Components
Differential Pressure
Sensors/Transmitter:
•Used for measuring diff. Pressure,
positive pressure and vacuum.
DPT1000 : AIR DIFF. PRESSURE TRANSMITTER
ST 3000 Pressure Transmitter

39. Air Handler Components
Coils :
Cooling Coils
Heating Coils
Coil Construction
•Copper with Aluminium fins,
•13 Fins /inch
•Number of Rows, I.e 4/6/8
depending on the latent heat
load & Bypass Factor.

40. Air Handler Components
The coil section of a AHU.
Note:
There may be a wide
variety of actual configurations

41. Air Handler Components
Valves & Actuators
Valve Types
2 Way or 3 Way
Actuator Types
Motorised
Magnetic
Pneumatic
Operation
On - Off,Floating,
Modulating

42. Air Handler Components
Energy Recovery :
A energy-recovery system is
often used in buildings where a
significant quantity of outdoor
air is used. Several types of
heat-recovery systems are
available
 Heat pumps
 Runaround systems
 Rotary heat exchangers
 Heat pipes.
Runaround systems
Heat Wheel

43. AHU Coil Control
The air handler cooling
component is accomplished
via chilled water coils or
via a refrigerant evaporator
coil absorbing heat in the
air stream.
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44. Practical Example
Mixed Air AHU :
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45. Practical Example
100% Outside Air AHU :
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46. Plant
Chiller Plant
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47. Chiller Plant
Chiller Plant systems are made up of:
–Chiller/Condenser Unit
–Chilled Water Pumps
–Condenser Water Pumps
–Cooling Towers
–Makeup Water Tank
–A/C Expansion Water Tank
TRANE Chiller
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48. Typical Commercial Chillers
What can we control on this system?
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49. Chiller Plant
Chiller Plant Concept :
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50. Typical Cooling Tower
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51. Typical Chiller Plant
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52. Boiler Plant
Boiler Plant systems are made up of:
–Boiler Units
–Primary Pumps
–Secondary Pumps
Typical Firetube Boiler
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53. Typical Commercial Boiler System
What can we control on this system?
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54. Boiler Plant
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55. Questions ??
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