Basics of HVAC.pdf

ACR

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

2. Slide 1
Panel
Moderator:
Bob Keingstein
Boss Facilities Services
631-361-7430
[email protected]

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

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

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

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

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

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

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

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

11. Slide 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

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

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

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

15. Slide 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?

16. Slide 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

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

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

19. Slide 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

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

21. Slide 21
SPLIT SYSTEM

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

23. Slide 23
VAV BOX
•Consists of VAV terminal
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
Variable Air Volume

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

25. Slide 25
HEAT REJECTION
(“HIGH TEMPERATURE”)
85F
75F95F
55F
45F
CONDITIONED
SPACE
105F
95F
HEAT GATHERING
(“LOW TEMPERATURE”)
REFRIGERATION
MACHINE
(REFRIGERATION CYCLE)
35F
COOLING
TOWER
95F DB
78F DB
HEAT
COMPRESSOR
COOLER
CONDENSER

26. Slide 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

27. Slide 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

28. Slide 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

29. Slide 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)

30. Slide 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.

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

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

33. Slide 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

34. Slide 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

35. Slide 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

36. Slide 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

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

38. Slide 39
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 = 18F across coil cooling Delta T = 25F for heating
CFM = Building Volume in Cubic Feet
Minute/Air Change
Delta T = Difference between entering and leaving DB = ΔT

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