This document provides an overview of basic air conditioning concepts and typical all-air HVAC systems. It describes the major components, including coils, fans, dampers, and control systems. Typical AC units discussed are rooftop packages, split systems, chilled water air handlers, and VAV systems. The document also outlines equipment types, control types, and provides some basic rules of thumb for HVAC design and operation.

1. Basic Concepts of Air
Conditioning
Prepared exclusively
for
COACH LEATHERWARE

2. Panel
Moderator:
Bob Keingstein
Boss Facilities Services
631-361-7430
bobk@bossfacilityservices.com
Slide 1

3. COIL COOL
AIR
HEAT
SOURCE OF
COOL AIR
• COIL •
Slide 3

4. TYPICAL ALL-AIR SYSTEM
S.A. DUCT
COIL COOL
AIR
HEAT
S.A.
FAN
Slide 4

5. TYPICAL ALL-AIR SYSTEM
S.A.
S.A. DUCT TERMINAL
COIL COOL
AIR
HEAT
S.A.
FAN
Slide 5

6. TYPICAL ALL-AIR SYSTEM
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
COOL WARM AIR
COIL AIR
HEAT
S.A.
FAN
Slide 6

7. TYPICAL ALL-AIR SYSTEM
R.A DUCT
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
COIL COOL
AIR
HEAT
S.A.
FAN
Slide 7

8. TYPICAL ALL-AIR SYSTEM
R.A.
FAN R.A DUCT
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
COIL COOL
AIR
HEAT
S.A.
FAN
Slide 8

9. TYPICAL ALL-AIR SYSTEM
R.A.
FAN R.A DUCT
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
R.A. DAMPER
COIL COOL
AIR
FRESH
OUTDOOR HEAT
AIR S.A.
FAN
O.A.
DAMPER
FILTER
Slide 9

10. TYPICAL ALL-AIR SYSTEM
E.A.
EXHAUST DAMPER
AIR R.A.
FAN R.A DUCT
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
R.A. DAMPER
COIL COOL
AIR
FRESH
OUTDOOR HEAT
AIR S.A.
FAN
O.A.
DAMPER
FILTER
Slide 10

11. Economizer
• Provides cooling to space when outdoor air
temperatures are below 55 degrees
• Switches over automatically from mechanical
cooling
• Adjusts R.A. and F.A. dampers to maintain space
temp
• May incorporate enthalpy control
• Mandatory in some states based on unit capacity
Slide 11

12. TYPICAL ALL-AIR SYSTEM
E.A.
EXHAUST DAMPER
AIR R.A.
FAN R.A DUCT
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
R.A. DAMPER
COIL COOL
AIR
FRESH
OUTDOOR HEAT
AIR S.A.
FAN
O.A.
DAMPER WATER PIPING
FILTER
CHILLED
WATER WATER
PUMP CHILLER
Slide 12

13. TYPICAL ALL-AIR SYSTEM
E.A.
EXHAUST DAMPER
AIR R.A.
FAN R.A DUCT
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
R.A. DAMPER
COIL COOL
AIR
FRESH
OUTDOOR HEAT
AIR S.A.
FAN
O.A.
DAMPER WATER PIPING
FILTER
HEAT
COOLING
TOWER
CHILLED
WATER WATER
PUMP CHILLER
CONDENSER
PUMP
Slide 13

14. TYPICAL ALL-AIR SYSTEM
E.A.
EXHAUST DAMPER
AIR R.A.
FAN R.A DUCT
R.A. GRILL
S.A.
S.A. DUCT TERMINAL
R.A. DAMPER
COIL COOL
AIR
FRESH
OUTDOOR HEAT
AIR S.A.
FAN
O.A.
DAMPER WATER PIPING
FILTER
HEAT
BOILER
COOLING
TOWER
CHILLED
WATER WATER
PUMP CHILLER
CONDENSER
PUMP
Slide 14

15. Equipment Types
• ROOFTOP PACKAGE UNIT
• SPLIT SYSTEM
• CHILLED WATER AIR HANDLER
• VARIABLE AIR VOLUME (VAV)
• AIR TO AIR HEAT PUMP
• Life expectancy 10 to 12 yrs for rooftop and split systems
• Expect increase in repair costs as equipment ages
• Typically largest expense to operation of store, energy/repair costs
• Repair or Replace?
Slide 15

16. Single Package Roof Top Unit
•Most common
•Entire hvac system is
located on mall roof
•Most common to have
roof leaks from roof curb,
condensate overflow or
roof punctures
Slide 16

17. Single Package Roof Top Unit
HEAT
COMP CONDR ELECTRIC
COIL HEATER
O.A.
FAN
E.A. S.A. DUCT
S.A.
R.A. DUCT TERMINAL
HEAT
Slide 17

18. Single Package Roof Top Unit
• Rooftop package unit
• Mounted on adaptor
curb
• Power exhaust and
economizer installed
Slide 18

19. Split System
• HVAC system split into 2 pieces
• Condensing unit located on roof (houses
compressor, condenser coil, condenser fan motor)
• Air handler located in space above ceiling (houses
blower assembly, evap coil, air filters)
• Connected electrically and with refrigerant piping
• Most prone to refrigerant leaks especially if long
distance between components
• Many times refrigerant lines are buried in
construction and inaccessible
Slide 19

20. SPLIT SYSTEM
CONDENSING UNIT HEAT
REFRIGERANT C
LINES C O
O N
M AIR
P D
R
AIR HANDLING
UNIT
COIL
O.A. POSSIBLE
FAN ELECTRIC
HEAT
E.A. S.A. DUCT
R.A. DUCT
HEAT OPTIONAL
SUPPLEMENTARY
HEATING
SYSTEM
Slide 20

21. SPLIT SYSTEM
Slide 21

22. Split System
• Air cooled condensing
unit
• Compressor, condenser
coil and condenser fans
• Connected to indoor air
handler
Slide 22

23. VAV BOX
•Consists of VAV terminal
Variable Air Volume
box located in the space
above ceiling
•May have supplemental
blower motor for positive
airflow to space
•May have air filtration
•Has a damper inside that
opens and closes on demand
from thermostat to allow
more or less airflow to
space
Slide 23

24. Major System Components
• Compressor
• Condenser coil
• Evaporator coil
• Condenser fan motor
• Evaporator fan motor
• Thermostatic expansion valve
• Evaporator blower assembly
• Economizers (Optional)
Slide 24

25. HEAT REJECTION
95F DB
(“HIGH TEMPERATURE”) 78F DB
HEAT
95F
105F
CONDENSER
CONDITIONED
SPACE 85F COOLING
TOWER
COMPRESSOR
95F 55F
75F
35F
COOLER
45F REFRIGERATION
MACHINE
HEAT GATHERING (REFRIGERATION CYCLE)
(“LOW TEMPERATURE”)
Slide 25

26. Compressor
• This component is the heart of the system..
• Pumps refrigerant and oil throughout
system
• Separates the high pressure side of the
system from the low pressure side
• If compressor fails, no cooling is possible
Slide 26

27. Condenser
• Condenser coil is what gets rid of the heat in the
system
• Can be water or air cooled, however most are air
cooled in retail application
• Located outdoors (air cooled)
• Fins on coil are subject to corrosion in salt water
environment. Special coatings can be applied.
• Fins are subject to damage from hail
• Traps dirt and requires periodic cleanings
Slide 27

28. Evaporator Coil
• Provides cold air to the space
• Located after the system air filters
• Return air is blown over the coil and chilled
• Removes moisture from air (condensate)
• Traps dirt that gets past air filters, reducing
cooling capacity (95% is bacterial)
• Requires periodic chemical cleaning
Slide 28

29. Evaporator Fan Motor
• Located behind condenser coil
• Draws ambient air across condenser coil
• System may have up to 4 or more motors based on
system capacity
• Motors are direct drive with fan blades attached
• Requires little if any maintenance (sealed
bearings)
Slide 29

30. TXV Thermal Expansion Valve
• Located at the evaporator coil
• Provides the correct amount of refrigerant to the
evaporator coil for proper cooling
• Separates the high pressure side of the system
from the low pressure side
• Failure could cause compressor failure and loss of
system cooling capacity
• Frequently overlooked in diagnosing system
problems
• Requires manual setting of superheat for proper
operation.
Slide 30

31. Evaporator Blower Assembly
• Consists of:
• Blower motor
• Pulleys and fan belts
• Bearings
• Fan shaft
• Fan wheels
• Housings
• Can be located indoors or outdoors
Slide 31

32. Control Types
• CONVENTIONAL THERMOSTAT
• DIGITAL PROGRAMMABLE
THERMOSTAT
• PNEUMATIC
• LCD SYSTEM
• MALL INTERFACE
Slide 32

33. Low Ambient Controls
• Low ambient controls
• May be added to air cooled systems that must
operate when outdoor temperatures are below 55
degrees
• Cycles condenser fan/s to maintain correct system
pressures
• Used when economizer is not present
• Much less costly to install
• Much more costly to operate
Slide 33

34. Conventional Thermostat
• Completely manual operation
• Will maintain a single heat or cool setting
• System must be switched from heat to cool
• No energy savings
• Will allow system to operate all night while store
is closed wasting energy
• Easy to tamper with
• Least expensive to install
Slide 34

35. Programmable Thermostat
• Provides auto
changeover from heat
to cool
• Provides up to 4
heat/cool settings per
24 hour period
• Can provide different
weekend settings
• Keyboard can be
locked out
• Set it and forget it
Slide 35

36. Pneumatic Thermostat
• Uses air provided by mall to operate
thermostat
• Very commonly used with VAV systems
• Least commonly found in malls
• Parts are fairly expensive
Slide 36

37. LCD Thermostat
• Used in newer stores
• Programmable type
• Can be dialed into by monitoring company
for data
Slide 37

38. Rules Of Thumb
1HP = 1KW = 1KVA 1KW = 3413 BTU
1 Ton Cooling = 12,000 BTU 1 Ton = 400 CFM
Retail = 380 SQ FT/ Ton cooling
Delta T = 18 F across coil cooling Delta T = 25 F for heating
CFM = Building Volume in Cubic Feet
Minute/Air Change
Delta T = Difference between entering and leaving DB = ΔT
Slide 39

39. Servpro of Great Neck /
Port Washington
For Further Information
Please Contact Us:
516-767-9600
ServproOfGreatNeck.com
Slide 40