1. HVAC-Systems-Fundamentals.pdf Somalia

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1. HVAC Systems Fundamentals
Heating, Ventilation, and Air Conditioning systems (HVAC)
is the technology of indoor and vehicular environmental
comfort.
Its goal is to provide thermal comfort and acceptable indoor
air quality.

2. Introduction to HVAC
Heating
Temperature control
systems that warm indoor
spaces using furnaces,
boilers, heat pumps, and
electric heating elements
to maintain comfortable
temperatures.
Ventilation
Air circulation systems
that exchange indoor
and outdoor air, remove
contaminants, and
ensure proper airflow
throughout buildings.
Air Conditioning
Cooling and dehumidification systems that remove
heat and moisture from indoor air to create
comfortable environments year-round.

3. Comfort Air Conditioning Systems
Primary Functions
•Temperature regulation
•Humidity control
•Air filtration
•Air circulation
These systems maintain optimal indoor comfort by
precisely controlling environmental factors that affect
human comfort and productivity.
01
Air Return
Warm indoor air is drawn into the
system through return ducts and
filtered to remove particles and
contaminants.
02
Cooling Process
Air passes over evaporator coils where
refrigerant absorbs heat, cooling and
dehumidifying the air stream. 03
Distribution
Conditioned air is distributed
throughout the building via supply
ducts and vents to maintain desired
temperatures.

4. Mechanical Cooling Systems
Compression
Compressor increases refrigerant pressure and
temperature, creating the driving force for heat
transfer.
Condensation
High-pressure refrigerant releases heat in the
condenser, changing from gas to liquid state.
Expansion
Expansion valve reduces pressure, allowing
refrigerant to cool rapidly before entering the
evaporator.
Evaporation
Low-pressure refrigerant absorbs heat from
indoor air, completing the refrigeration cycle.

5. Refrigeration cycle
1) Condensing coil 2) Expansion valve
3) Evaporator coil 4) Compressor

6. Understanding Refrigerants
R-410A
Most common residential
refrigerant. Non-ozone
depleting, higher pressure
operation. Standard for new
installations since 2010.
R-32
Newer eco-friendly option
with lower global warming
potential. Increasingly used
in residential and light
commercial applications.
R-22 (Phased Out)
Legacy refrigerant being phased out due to ozone depletion.
Still found in older systems requiring specialized handling.
Safety Note: Always follow EPA regulations when handling
refrigerants. Proper certification and recovery equipment
are required by law.

7. Cooling System Options
Split Systems
Most popular residential
option. Outdoor condensing
unit connected to indoor
evaporator. Quiet operation
and flexible installation
options.
Packaged Units
All components housed in
single outdoor unit. Common
for commercial applications
and homes without
basements or crawl spaces.
Ductless Mini-Splits
Individual room control
without ductwork. Perfect
for additions, older homes, or
zone-specific cooling
requirements.

8. Central Air Conditioning Systems
Key Components
Outdoor Condenser Unit
Contains compressor,
condenser coil, and fan.
Rejects heat from the
refrigeration system to
outdoor air.
Indoor Air Handler
Houses evaporator coil,
blower fan, and filter.
Circulates conditioned
air throughout the
building.
Ductwork System
Network of supply and return ducts that distribute cooled
air and return warm air for reconditioning.

9. Window and Portable Units
Window Units
•Self-contained cooling system
•Mounts in window opening
•5,000 to 25,000 BTU capacity
•Cost-effective for single rooms
Portable Units
•Freestanding mobile design
•Vents hot air through window kit
•No permanent installation required
•Lower efficiency than fixed units
These compact solutions provide targeted cooling for specific
areas without the complexity of central systems. Perfect for
apartments, dormitories, or supplemental cooling needs.

10. Commercial HVAC Systems
Rooftop Units (RTUs)
Self-contained systems
mounted on building roofs.
Common for retail and office
buildings.
Chilled Water Systems
Central chiller plant distributes
cold water to air handlers
throughout large facilities.
Variable Air Volume
VAV systems adjust airflow to
different zones based on cooling
demand and occupancy.
Heat Recovery Systems
Capture waste heat from one
area to heat other areas,
improving overall system
efficiency.

11. Your HVAC Journey Begins
Master the Fundamentals
Understanding refrigeration
cycles, system components, and
safety procedures forms your
professional foundation.
Develop Technical Skills
Hands-on experience with
installation, maintenance, and
troubleshooting builds expertise
and confidence.
Pursue Certification
EPA certification and industry
credentials open doors to
advanced positions and
specialized work opportunities.
The HVAC industry offers stable careers with growing demand. Master these fundamentals, and you'll be
prepared to tackle any cooling challenge that comes your way.

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