Cooling Towers 9.30.20

www.b-ct.net
Sight-Specific Customized to
Your Equipment and Facility
Cooling Tower/
Chiller
General
Operations
Illustrations and Notes arranged by
Sedley Parkinson, Instructor
B & CT Training LLC
www.b-ct.net
Sep 2020

Contents
Fluid Dynamics ........................................................................................................................................................................ 3
Valves .................................................................................................................................................................................. 3
Water Hammer: Valve Induced....................................................................................................................................... 5
Backflow Prevention ....................................................................................................................................................... 6
Pumps.............................................................................................................................................................................. 7
Water Flow Dynamics and Electricity Correlation .......................................................................................................... 9
Psi ...................................................................................................................................................................................... 10
Vapor Pressure .............................................................................................................................................................. 10
Pressure Measurement ................................................................................................................................................. 12
Ideal Gas Law ................................................................................................................................................................ 13
Heat Pumps ................................................................................................................................................................... 14
Water ................................................................................................................................................................................ 17
°F vs. Btu ........................................................................................................................................................................ 17
Steam Table................................................................................................................................................................... 22
Water to Ice Expansion ................................................................................................................................................. 23
pH .................................................................................................................................................................................. 24
Aquastat ........................................................................................................................................................................ 25
Antifreeze ...................................................................................................................................................................... 26
Pressure Reducing Valve (PRV) ..................................................................................................................................... 28
Heat Exchangers ............................................................................................................................................................ 31
Electricity ............................................................................................................................................................................... 32
DC vs AC ............................................................................................................................................................................ 32
VFD: Affinity Law ............................................................................................................................................................... 33
LEED Program .................................................................................................................................................................... 34
Thermocouples ................................................................................................................................................................. 35
The Grid ............................................................................................................................................................................. 36
Cooling Towers: Dynamics .................................................................................................................................................... 37
Saturation Curve ........................................................................................................................................................... 37
Evaporative Cooling ...................................................................................................................................................... 40
Relative Humidity .......................................................................................................................................................... 41
Psychrometric Chart ...................................................................................................................................................... 42
Size: Tonnage ................................................................................................................................................................ 44
Cooling Tower Types ..................................................................................................................................................... 45
Cooling Tower Components .............................................................................................................................................. 50
pg. 1

Fill .................................................................................................................................................................................. 50
Water Level Controllers ................................................................................................................................................ 53
Immersion Heaters ........................................................................................................................................................ 54
Cooling Tower Scale .......................................................................................................................................................... 55
Source: CaCO 3 and Silica ............................................................................................................................................... 55
Prevention ..................................................................................................................................................................... 56
Scale Removal ............................................................................................................................................................... 58
Corrosion ........................................................................................................................................................................... 59
Galvanic Corrosion ........................................................................................................................................................ 59
Rust ............................................................................................................................................................................... 60
Biological Growth ............................................................................................................................................................ 62
Algae, Yeast, Molds ...................................................................................................................................................... 62
Legionella ..................................................................................................................................................................... 63
Chillers ................................................................................................................................................................................. 69
History .............................................................................................................................................................................. 69
Basic Composition ........................................................................................................................................................... 70
Refrigerants ....................................................................................................................................................................... 75
Corrosion ........................................................................................................................................................................... 78
MIC ................................................................................................................................................................................ 78
Eddie Current Testing ................................................................................................................................................. 80
Chiller Compressor Types ................................................................................................................................................. 81
Absorption Cooling ........................................................................................................................................................... 89
Ammonia/Hydrogen Refrigeration ............................................................................................................................... 89
Lithium Bromide (LiBr) Absorption Chillers .................................................................................................................. 90
Free Cooling ...................................................................................................................................................................... 91
Chiller Surge ...................................................................................................................................................................... 92
pg. 2

Fluid Dynamics
Valves
Ball
Gate
Butterfly
Globe
Pressure Regulators
are usually globe
valves
Diaphragm
Stem pushes down on
rubber gasket
Spring Check
Swing
Check
Lift
Check
pg. 3

Actuators remotely open and close valves
Manual override
Motorized actuators close slowly,
avoiding water hammer
A Solenoid is an electric actuator: electricity creates a
temporary magnet pushing the permanent magnet down.
pg. 4

Water Hammer: Valve Induced
pg. 5

Backflow Prevention
Symbol
Backflow means the undesirable reversal of flow of a
liquid, gas or solid into the potable water supply.
Back-siphonage occurs when higher pressure fluids, gases,
or suspended solids move to an area of lower pressure
fluids.
Q.: How often does the backflow prevention assembly
need to be tested?
A.: On installation and at least once a year thereafter by
a licensed backflow tester.
pg. 6

Chemical Feed Pumps
Pumps
Speed:
How often
Chemical
injection
quill
Stroke:
How deep
Check
valve
Peristaltic Chemical Feed Pumps
Pinch process does not lose prime, but
tube needs to be replaced periodically
pg. 7

Feed Water Pumps
Horizontal Screw Feed Water Pumps
Vertical Multistage
(multiple impellers)
Feed Water Pumps
Also called a “can pump”
(like a tin can)
Parallel Connection:
flow increase constant pressure
Series Connection:
pressure increase constant flow
pg. 8

Water Flow Dynamics and Electricity Correlation
Parallel:
Amps increase, volts stay the same
Series:
Volts increase, amps stay the same
Volts measure how hard the electricity is pushing (Electrical Force)
Amps measure current, or how much electricity is flowing [Ah = Amp-hours]
Watts measure how much electricity is going through the circuit (Power)
Ohms (Ω) measures Resistance
Note correlation
Pressure: psi → Volts
Flow: gpm → Amps
Hydraulic HP → Watts
252 calories = 1 Btu
1 ft 3 of natural gas ≈ 1020 Btu
1 kilowatt·hr (kwh) of electricity = 3413 Btu
1 pound of Coal ≈ 9,200 Btu
1 pound of gasoline ≈ 14,300 Btu
1 pound of diesel or fuel oil ≈ 16,000 Btu
1 Therm = 100,000 Btu
1 Dekatherm (DTH) = 1,000,000 Btu
0.293 Watts = 1 Btu/hr
pg. 9

Psi
Absolute Zero = Perfect Vacuum
Vapor Pressure
0
Vacuum
Maximum water
content in air =
saturation point
Evaporation or
Vaporization
Vaporization >
Condensation
Vaporization =
Condensation
Equilibrium
Pressure changes with Temperature (molecules
move around more when heated)
Saturation Point
(Equilibrium) changes with
Temperature and Pressure
and becomes the
Saturation Curve
pg. 10

Atmospheric vs Gauge
psig
(gauge)
psia
(absolute)
H 2O
boiling pt
Perfect Vacuum -14.7 0 °F
Near Vacuum -14.5 0.2 53°
Mt. Everest -5.6 9.1 157°
Lake Tahoe -3.0 11.7 200.7°
Sea Level 0 14.7 212°
Dead Sea 0.8 15.5 215°
Space = a vacuum
psia = 0
psig = -14.7
Sea Level =
1 atmosphere
= 14.7 psia
= 0 psig
Mt. Everest = 29,029 ft
LakeTahoe= 6224 ft
Dead Sea = -1378 ft
High altitude cooking instructions: 3500 to 6500 ft
Increase simmer time to 19 min (with lower boiling
temperature, it takes longer to cook food.)
Vacuum
pump
Vacuum
jar
pg. 11

Pressure Measurement
Bourdon Tube Gauges: flattened
hollow tubes that s-t-r-e-t-c-h out
when introduced to pressure.
Digital pressure
gauges do not
need a pig tail
and can
automatically log
measurements
into a computer.
Compound gauges measure both pressure
and vacuum. Note: inches of mercury
(a perfect vacuum = 30” Hg)
0 psia = -1 bar (metric) = -100 kPa (metric)
1 atm = 100 kPa = 1013 mbars = 760 mmHg = 30 inHg = 14.7 psia = 0 psig
Vacuum gauge
pg. 12

Ideal Gas Law
When Temperature↑ and Volume stays the same, then Pressure↑
= BOILER
When Pressure↑ and Volume stays the same, then Temperature↑ = AIR COMPRESSOR
The INTERCOOLER uses water or
outside air to cool compressed
air in-between stages.
2 nd Stage
1 st Stage
When Pressure↓ and Volume stays the same, then Temperature↓ = Propane Tank
ICE !
P↓ × V c = T↓ : Refrigeration
(Restricting Orifice)
Hot
Cold
Various types of expansion valves
Air Conditioning
* Simplified for training purposes. Actual:
pg. 13

Heat Pumps
Around 37°F many heat pumps reach what is
called the balance point where the heat pump
needs to run constantly to maintain a
comfortable indoor temperature. Efficiency
drops as you approach this point.
Reversing Valve
pg. 14

Dehumidifier
DEHUMIDIFIER
Wood Dehumidification Kiln
HVAC Dehumidification Air Handler
pg. 15

Temperature
: through nonmoving or solid parts
: through moving substances, such
as water, steam, or air
: through energy waves, even
travels through a vacuum (such as the sun
transfers heat to Earth through space)
Latent heat of
liquefaction
Latent heat of
vaporization
vaporizing →
BTUs
Latent Heat:
BTUs
← condensing
pg. 16

Temperature
Water
°F vs. Btu
@ 0 psig = 1 Atm = sea level
Saturated Steam = steam at the boiling pt.
Superheated
(above the
boiling pt.)
32°F 212°F
0°C 100°C
970.3 BTUs to boil 1 # of H 2O
Water at 32°F
contains 0 BTUs
(beginning point for
BTU measurement)
-144BTU 0BTU 180BTU 1150.3BTU
Heat Content
1 BTU = heat needed to change 1 lb. of water 1º F
To change 1 lb of:
Ice 1º F, add 0.5 Btu
Steam 1º F, add 0.45 Btu
How many BTUs does one pound of steam contain at 212°F at Sea Level?
32 ºF water to 212 ºF water takes 180BTU/lb. 180
212 ºF water to 212 ºF steam takes 970.3BTU/lb. +970.3
1150.3 BTUs
pg. 17

Sea Level
Pressure
Phases of Water
°F vs psi
Pressure vs. Temperature
Freeze Point
Curve
Evaporation
Curve
14.7 psia
= 0 psig
= 1 atm
= 1 bar
Solid
Sea Level
Vapor
Triple
Point
(not to scale)
Absolute Zero
(Theoretical)
Temperature
32°F
0°C
212°F
100°C
Solid
Triple
Point
Vapor
Where Freeze Point Curve, Evaporation Curve and Sublimation Curves Meet
= 0.09psia and 32.02°F
pg. 18

Freeze Dryers
Home Unit
Freeze Dryer
Sublimation
= Freeze Dryers
Low temperature and pressure
Vacuum
Chamber
2. About 90% of the food’s
moisture is drawn off by
sublimating the ice at
temperature as low as -60º F
pg. 19

Water to Vapor Expansion
When Temperature ↑ and Pressure stays the same, then Volume must ↑
v = 0.01672 ft 3
Now imagine a 500 gallon boiler rupturing and instantly filling the
building with 111,700 ft 3 (100 hot air balloons) of flash steam
1865 Sultana
2000 returning Union
POW’s died from boiler
explosion
Denver: 500 gallon boiler explosion
Today, the most common reasons
for boiler explosions are improper
purge cycle and low water cut-off
failure.
pg. 20

Cavitation:
Implosion of low pressure steam bubbles back to water
causing miniature shock waves, damaging metal surface.
Propeller Cavitation
Valve Cavitation:
sounds like gravel
moving through pipe
pg. 21

Psig
Inches of Hg (Vacuum)
Steam Table
Gauge
Pressure
Psia
Boiling
Point
ºF
Btu content of
1 lb. of water
at B.P.
Btu needed to
turn 1 lb. of water
at B.P. into steam
Btu content
of saturated
steam
Volume
of water
ft 3 /lb
Volume
of steam
ft 3 /lb
29.7 0.09 32 0 1075.8 1075.8 0.01602 3306
29.5 0.2 53 21 1063.8 1085.0 0.01603 1526
27.9 1.0 102 70 1036.3 1106.0 0.01614 334
19.7 5.0 162 130 1001.0 1131.0 0.01641 73.5
9.6 10.0 193 161 982.1 1143.3 0.01659 38.4
7.5 11.0 198 166 979.3 1145.0 0.01665 35.1
5.5 12.0 202 170 976.6 1146.6 0.01667 32.4
3.5 13.0 206 174 974.2 1148.1 0.01667 30.1
1.4 14.0 210 178 971.9 1149.5 0.01670 28.0
0 14.7 212 180 970.3 1150.3 0.01672 26.8
1 15.7 216 184 967 1152 0.01675 24.8
2 16.7 219 187 965 1153 0.01677 23.4
5 19.7 227 196 960 1156 0.01683 20.1
10 24.7 240 208 952 1160 0.01692 16.3
15 29.7 250 219 945 1164 0.01700 13.8
20 34.7 259 228 939 1167 0.01708 11.9
25 39.7 267 236 933 1170 0.01714 10.5
30 44.7 274 243 928 1172 0.01721 9.4
40 54.7 287 256 919 1176 0.01732 7.8
50 64.7 298 267 911 1179 0.01743 6.7
60 74.7 307 277 904 1182 0.01752 5.8
70 84.7 316 286 898 1184 0.01761 5.2
80 94.7 324 295 891 1186 0.01769 4.7
90 104.7 331 302 886 1188 0.01777 4.2
100 114.7 337 309 880 1189 0.01785 3.9
110 124.7 344 316 875 1191 0.01792 3.6
120 134.7 350 322 870 1192 0.01799 3.3
130 144.7 355 328 866 1193 0.01806 3.1
140 154.7 360 333 861 1195 0.01812 2.9
150 164.7 366 339 857 1196 0.01818 2.7
200 214.7 388 362 837 1199 0.01847 2.1
250 264.7 406 382 820 1202 0.01873 1.7
etc.↓ 300 417 394 809 1203 0.01890 1.54
400 446 424 781 1205 0.01934 1.16
450 456 437 767 1205 0.01955 1.03
500 467 449 755 1204 0.01975 0.93
600 486 472 732 1203 0.02013 0.77
900 532 527 669 1195 0.02123 0.50
1200 567 572 612 1183 0.02232 0.36
1500 596 612 556 1167 0.02346 0.28
2000 636 672 463 1135 0.02565 0.19
2500 668 731 361 1191 0.02860 0.13
2700 680 756 312 1068 0.03027 0.11
3206.2 705 903 0 903 0.05053 0.05053
Sea Level
Supercritical Steam refers to conditions
above 3206.2 psia and 705 °F where steam
and water reach a new phase.
pg. 22

Water to Ice to Expansion Ice
Expansion
slightly
negative
9 %
slightly
positive
slightly
positive
Water to Ice Volume Expands 10%
Which is about the same as:
10 ft 3 water making 11 ft 3 of ice
Hexagonal shape
60°
…, and Ice Floats
(less dense)
60°
Breweries have high steam demand
…, and breaks lines
pg. 23

pH
Hydrochloric Acid
(HCl)
H + OH -
10 0 = 1 = 100%
10 -14 = .00000000000001
Stomach Acid
(weak HCl)
10 -1 = .1 = 10%
10 -13 = .0000000000001
Vinegar
Lemon Juice
10 -2 = .01 = 1%
10 -12 = .000000000001
The concept of pH was
first introduced in 1909
by Danish chemist
Soda Pop
Orange Juice
10 -3 = .001 = .1%
10 -11 = .00000000001
Tomato Juice
Acid Rain
10 -4 = .0001 = .01%
10 -10 = .0000000001
Eye Drops
Normal Rain
10 -5 = .00001
10 -9 = .000000001
Saliva
Urine
10 -6 = .000001
10 -8 = .00000001
Pure Water
10 -7 = .0000001 =
10 -7 = .0000001
Sea Water
Swimming Pools
10 -8 = .00000001
10 -6 = .000001
Baking Soda
10 -9 = .000000001
10 -5 = .00001
Great Salt Lake
10 -10 = .0000000001
10 -4 = .0001
Ammonia (NH4OH)
Soaps
10 -11 = .00000000001
10 -12 = .000000000001
10 -3 = .001
10 -2 = .01
At pH > 7, OH -
(hydroxide) becomes
the active ion.
Bleach
Oven Cleaner
10 -13 = .0000000000001
10 -1 = .1
OH -
Drain Cleaner
Caustic (NaOH)
10 -14 = .00000000000001
H +
10 0 = 1
HCl (acid) + NaOH (base) → H 2O (pH 7) + NaCl
(salt water)
pg. 24

Aquastat
Aquastat sets hot water
boiler temperature ranges
STRAP-ON SURFACE
TEMPERATURE PROBE
Temperature probe bulb
fits into thermowell.
Low Limit:
Turns on the burner
view from inside vessel
Differential:
Normal operating range
above low limit (turns off burner)
Triple Aquastat
High Limit:
Safety Cutoff
Manual reset indicates this is a high
temperature limit safety cutoff
pg. 25

Temperature °F
Antifreeze
Prevents freezing in Closed Loops
during shut downs.
Refractometers use light to
measure glycol’s freeze point
PG
C₃H₈O₂
Composition
EG
C2H6O2
Food Grade
(You can drink it)
Safety
Toxic
(Follow proper use and
disposal guidelines)
Nitrites are added to prevent
corrosion.
Cost (as of 2014)
Inhibitor = Nitrites
= corrosion prevention
Because of safety, food-processing closed loop
boilers generally are charged with Propylene
Glycol.
Use
Because of cost, nonfood-processing closed loop
boilers generally are charged with Ethylene Glycol.
Glycols
@

Steam Trap Trouble Shooting
Pyrometer
A significant drop in temperature
indicates that a steam trap is
functioning properly.
Thermal Imager
pg. 27

P↓ × Pressure V c = T↓ (Ideal Reducing Gas Law) Valve (PRV) Restricting Orifice
Manual-Bolt
adjust
Auto-Pressurestatic adjust
Auto-Thermostatic
adjust
Hollow Capillary
Tubes
Steam Pressure/Temperature Reducers
operate on the exact same principles as
Chiller/AC TXVs
Wood drying kiln
Internally Equalized
pg. 28
Externally Equalized

Demineralizer (DeMin Water)
Not only softens the water by removing positive ions such as Ca +2 and Mg +2 but
also removes undesired negative ions such as SO 4
-2
, Cl - , CO 3
-2
, HCO -3 .
Single Bed Demineralizer
Regeneration
Mixed Bed Demineralizer
pg. 29

Reverse Osmosis (Membrane Filtration)
No salt or other chemicals are needed, however,
the costs of replacement membranes, the
electricity needed to pump the water through the
membranes, and the excess higher concentration
waste water all need to be calculated in when
considering this form of water treatment.
pg. 30

Heat Exchangers
U-Tube
= Two pass
Shell and Tube
Straight Tube =
One pass
Plate and Frame
BPHE: Brazed Plate Heat Exchanger
No gaskets
Higher efficiency means
equivalent heat transfer can be
achieved with smaller units
pg. 31

Electricity
DC vs AC
Error! Bookmark not defined.
Tesla vs. Edison
Direct Current:
One Way Flow
Single Phase AC
Alternating Current: Switches Back and
Forth from Positive to Negative
Hertz = rotations per second
Three Phase AC
pg. 32

VFD: Affinity Law
Variable Frequency Drive
The Affinity Law
Law 1a) Air flow is directly proportional to fan speed.
Example: When fan speed doubles, air flow doubles.
1a) Fan Speed ↑ = Air Flow ↑
Law 1b) Torque increase is proportional to the square of the fan speed increase.
Example: When fan speed doubles, torque increases four times
When fan speed triples, torque increases nine times 1b) (Fan Speed ↑ ) 2 = Torque ↑
Law 1c) Power required is proportional to the cube of fan speed increase.
Example: When fan speed doubles, power required is six times
1c) (Fan Speed ↑ )
When fan speed triples, power required is 27 times
3 = Power ↑
Significant Energy Savings
Use only the fan speed your system is calling for.
A 100 HP fan running at half speed uses the
same energy as a 13 HP motor!
(½) 3 x 100HP = (1/8) x 100HP = 13HP
Equipment Savings
Single-speed motors start abruptly:
High starting torque
High starting current surges (up to 8 times)
Variable speed drives gradually ramp up the motor.
pg. 33

LEED Program
In the United States and in a number of
other countries around the world, LEED
certification is the recognized standard for
measuring building sustainability.
Four Certification Levels
pts possible)
The LEED green building rating system -- developed
and administered by the U.S. Green Building
Council, a Washington D.C.-based, nonprofit
coalition of building industry leaders -- is designed
to promote design and construction practices that
increase profitability while reducing the negative
environmental impacts of buildings and improving
occupant health and well-being.
Out of 110 possible points
LEED certification is helping to steer the HVAC industry towards higher efficient
boilers and chillers. In the long run, these systems pay for themselves.
☺
Out
In ☺
pg. 34

Thermocouples
A small electric current is
created when heated.
Thermopile:
End bulb has multiple wire “twistings”,
produces larger electron flow.
Thermocouple:
Single twisted wire sensor
Temperature probe
Thermopile
Pilot
Copper capillary tube protects the inner
insulated wire and also conducts electricity
back to the head where voltage can be
measured (usually in millivolts).
Spark Ignitor
Common in
atmospheric burners
pg. 35

The Grid
the Grid
Base Load Power Plants run
continuously while Intermediate and
Peak Plants meet local load demands
Transmission
Energy Losses
pg. 36

Cooling Towers: Dynamics
Saturation Curve
Saturation Curve
1000gH20 / Kg Air
all air is water vapor
Equilibrium = Saturation Curve = Dew Point
Water vapor in air
400g
300g
200g
100g
0 K= -273°C= -460°F
No water vapor in air
No molecular movement
Absolute zero temperature
temperature increase →
373 K=100°C=212°F
All water vaporized
(@0psig)
0g
Water droplets, suspended in the air,
form as humid air temperature drops
past the saturation curve.
←temperature drop
H 2O falls out as dew and frost,
OR rain and snow.
f
r
o
s
t
d
e
w
Freeze Point
pg. 37

Air Moisture Content →
Adiabatic Process
Moist air rises over mountains: lower air pressure,
vapor condenses on dust particles forming
suspended droplets or ice crystals (clouds).
Descending clouds increase in
air pressure, clouds evaporate
back into vapor = Rain Shadow.
Rain/Snow →
Temperature Increase →
Same principle applies
to large air masses
pg. 38

Extreme
Precipitation
A combination of the adiabatic process and
the inability of cold air to hold moisture, the
Dry Valleys of Antarctica is said not to have
any measurable precipitation for over
2,000,000 years.
The Brahmaputra Mountains in Eastern
India reports the highest average rainfall of
467 inches per year.
pg. 39

Evaporative Cooling
Rapid expansion of volume during phase change (liquid to gas) =
temperature drop, the lost energy is carried away by vapor molecules.
Evaporation
Saturation Point,
the air can’t hold
any more water.
(Wet Bulb)
New Higher
Air Moisture
Content
Original Air
Moisture
Content
New Lower Air
Temperature
Original Air
Temperature
Direct Evaporative Cooling
(effectiveness reduced in high humidity)
pg. 40

Relative Humidity
Relative Humidity
100% 1 Kg H2O/Kg air
= pure steam
80% 800g/Kg air
% Relative Humidity = Water
content of air compared to
how much water the air could
hold at that temperature.
50%
40%
30%
20%
10%
500g/Kg air
400g/Kg air
300g/Kg air
200g/Kg air
100g/Kg air
Absolute zero
The higher the
temperature, the
more water the air
can hold.
100ºC
Boiling Point at sea level
< 100% RH: evaporation can still take place and temperature drops.
Wet Bulb represents maximum possible
evaporation temperature drop.
100% Relative Humidity =
Saturation Curve
pg. 41

Psychrometric Chart
Psychrometry
Sling Psychrometer
Digital Psychrometer
(accuracy may vary, depending on model)
Incoming Air
Dry Bulb = 90°F
@10% RH
Outgoing Air
Wet Bulb = 60°F
@100% RH
pg. 42

pg. 43

AC Size: Tonnage
- 144 BTU / lb.
The unit of measure used in air conditioning
to describe the cooling capacity of a system.
One ton of cooling is based on the amount
of heat needed to melt (or freeze) one ton
(2000 lbs.) of ice in a 24 hour period.
1 ton cooling = 2000 lbs. x 144 BTU/lb.
= 288,000 BTU/day
= 12,000 BTU/hr.
1000 to 5000 ton water cooled
(capacity depends on RH)
1 ton window AC
50 ton rooftop air cooled
Dry Cooling
No water evaporation
Dry cooling can only reach
down to dry bulb temperature.
pg. 44

Cooling Tower Types
Natural Draft Cooling Towers
(no electric fans)
Hyperboloid Natural Draft Cooling Towers:
patented in 1918
hot moist air ↑
Natural Draft
cool air →
pg. 45

Forced Draft Cooling Towers
pg. 46

Induced Draft Cooling Towers
FRP
FRP = Fiber Reinforced Plastic (Fiberglass)
PVC = Polyvinylchloride
Wood Frame
HDPE = High Density Polyethylene Plastic (Recycled)
pg. 47

Cross Flow
Fill Basin
Splash
Guards
Counter Flow
Drift
Eliminator
pg. 48

Open Recirculating
Cooling Tower
Fill
Drift Eliminator
Closed Recirculating
Cooling Tower
Radiator Insert
Galvanized steel
Closed system:
Notice pipe locations
pg. 49

Cooling Tower Components
Fill
Drift Eliminators
Blade
Cellular
Packaged Film Fill
hot water in↓
hot water in↓
moist air out↑
hot water in↓
moist air out↑
moist air
out
cold water out↓
dry air in↑
cold water out↓
dry air in↑
cold water out↓
dry air in↑
pg. 50

Stackable Sheet Film Fill
pg. 51

Splash Fill
Horizontal
V Bars
Ladder
Looking from the bottom up
Looking from the top down
pg. 52

Water Level
Water Level Controllers
Controllers
Electric Sensor
Controller
Hi
Alarm
Hi
Lo
Ground
Pumps &
valves
Conductive Liquid
Ball Float
Slide
Diaphragm
Equilibrium
pg. 53

Immersion
Heaters
Immersion Heaters
Prevents winter freezing
Thermowells protect thermometers
hollow
pg. 54

Cooling Tower SCALE
Cooling Tower Scale
Source: CaCO3 and Silica
CaCO3
Calcium Carbonate
Mg(OH) 2
Magnesium Hydroxide
CaSO 4
Calcium Sulfate
SiO 2
Silica
Side stream Filter
pg. 55

Hardness →
SCALE Prevention CONTROL #1
Bleed Off
Stay under the saturation point. Keep the cycles
of concentration in check by using bleedoff
controls.
Scale
forms
Saturation
maximum
Supersaturated
Conductivity
set point.
1 cycle
= raw water
2 cycles
= twice as concentrated
due to evaporation
3 cycles
= three times
4 cycles
Electric Motor Actuator slowly opens
(helps prevent water hammer)
Signals actuator to bleed off
system until conductivity drops
Inline probe measures
how well electricity flows
between electrodes in
water then converts
reading to Conductivity.
Electromagnetic
Solenoid
pg. 56

Hardness→
OH¯ Concentration→
SCALE CONTROL #2
Phosphates and pH
Use scale control chemicals.
Polymers/HEDP keep crystals in suspension.
Phosphonates disrupt formation of crystal lattices.
Nalco solid chemical dissolver/dispenser
New maximum
Proper use of chemicals
raises the saturation line,
enabling higher cycles and
water conservation.
Supersaturated
New conductivity
set point.
Old saturation
maximum
From 2.5
to 3.4 cycles
1 cycle 2 cycles
3 cycles
4 cycles
SCALE CONTROL #3
IF pH is high, add acid.
High concentration of
OH¯ ions (high pH)
lowers the solubility of
calcium carbonate, it
precipitates out and scale
forms.
Scale
forms
7 pH → 9 10 11 12 13 14
pg. 57

Scale Removal
Pressure Spray & Vacuum
CaCO 3 + 2HCl (acid) CaCl 2 + H 2 O + CO 2 (gas)
Dilute HCl
Scale Chips
Acid
(Inhibited with Nitrites)
Municipalities generally do not accept pH

Cathode
Corrosion
Galvanic Galvanic
Corrosion
Corrosion
mild steel vs stainless steel
brass vs steel
Metal
Oxides↓
Cathode
(zero corrosion)
Anode
e -
Cathode
(zero corrosion)
Metal
Oxides→
Anode
e -
Anode
Tubercles
←(zero corrosion)
Cathodic ←
→Anodic
Plastic/Nylon
sleeves/gaskets
More anodic→ corrodes first
←Further apart, stronger galvanic effect→
Coated bolts/screws
Dielectric Union
pg. 59

Rust
Dissolved oxygen “steels” (oxidizes) electrons
from Iron. A weak but significant electrical
current forms creating Anode (+) and
Cathode (-) areas.
O 2 + 4e¯+ 2H 2O → 4OH¯
Fe +2
Anode
2e¯
Cathode
Fe +2 ions are released into the water along with
the newly formed OH¯ ions.
Fe +2
Fe
Anode
Cathode
Fe +2 combines with 2OH¯ and precipitates out as rust.
Fe +2 + 2OH¯ → Fe(OH) 2
rust
rust
Cathode
Fe
Fe
Cathode
Anode
Iron Rust
White Rust = Zinc rust on
galvanized metal
(selective leeching).
pg. 60

H + Concentration→
.
Acidic waters have high H + ion concentrations which react with electrons at
the cathode releasing hydrogen gas: 2H + + 2e¯ → H 2 (g).
Corrosion is accelerated.
0 ← pH 3 5 7
Group VII
Halogens
Like Oxygen, the halides Bromine, Chlorine and Iodine are
also “looking” for electrons which are readily available at the
cathode. At high levels, these oxidizing biocides have a
tendency to cause corrosion.
Oxidizing
Biocides
Road Salt (NaCl) Corrosion
pg. 61

Biological Growth
Algae, Yeast, Molds
Unchecked mold and algae growth restricts air
flow plugs lines and ultimately reduces efficiency.
pg. 62

Legionella Bacteria
History
The first recognized outbreak occurred at the Bellevue Stratford during an American
Legion conference in 1976 in Philadelphia. As many as 221 people were given
medical treatment, and 34 died from extreme pneumonia symptoms. The U.S.
Centers for Disease Control and Prevention mounted an unprecedented investigation
and, by September, the focus had shifted from outside causes, such as a disease
carrier, to the hotel itself. After 5 months of research, the Legionellosis bacterium
was finally identified; it was in the cooling tower. Normally, the bacterium dies
when the water droplets in the mist spray leaving the cooling tower dries up in the air.
However, at the Stratford, the mist spray from the cooling tower exhaust fans was
being sucked back in by the building’s fresh air intake!
Major Legionella Outbreaks
Non-communicable
(cannot be transferred
between humans)
Year Location Cases Died Bacteria Source
1976 Philadelphia 221 34 Cooling Tower
1985 Stafford, UK 175 28 Cooling Tower
1999 Bovenkarspel, Netherlands 200 32 Humidifier & Whirlpool
2000 Melbourne, Australia 125 4 Cooling Tower
2001 Murcia, Spain 449 6 Cooling Tower
2002 Barrow, UK 172 7 Cooling Tower
2003 Pas-de-Calais, France 86 18 Cooling Tower
2005 Fredrikstad, Norway 56 10 Air Scrubber
2011 Playboy Mansion, Los Angeles 123 0 Hot Tub
Due to early
intervention
Legionella are more
difficult to kill in areas
with high slime build up.
Between 1995 and 2005, over 32,000
worldwide cases of Legionnaires'
disease and more than 600 outbreaks
were reported to the European Working
Group for Legionella Infections (EWGLI).
pg. 63

Infected lung
Water test
Urine test
pg. 64

BIOCIDES
Oxidizing antimicrobials kill by “stealing” electrons from critical atoms
disrupting internal functions or damaging cell walls.
Nonoxidizing kill by replacing critical molecules with “poison” molecules.
Oxidizing
Biocides
Chlorine, Bromine, and Iodine “steel” (oxidize)
electrons from molecules of living cells and
they die or fail to reproduce.
Note: No. 53 Iodine (I)
is also a medicinal
disinfectant.
Hypochlorite Ion
Hypochlorous Acid
Chlorine Gas/ Tablets /Bleach + H 2 O → OCl ¯ + HOCl + OH¯
Ions attack
cell walls.
Acids attack
internal cell
functions.
Bromine Tablets + H 2 O →
OBr ¯ + HOBr + OH¯
Chlorine
Hypobromite Ion
Hypobromous Acid
Bromine
Nalco OxySlugger dispenser
pg. 65

Oxidizing Biocides
Ozone (O3)
e¯
1) 1) Generated on site and does not
require storage.
2)
2)You cannot over-dose as unused
ozone escapes out of the water and
reverts to oxygen.
3) Disinfection qualities are not
dependent on pH, nor does the
addition affect the pH of water.
4) Effectiveness can be measured with
an ORP (Oxidation/Reduction
Potential) meter.
5) Less corrosive than chlorine and
bromine in water.
6) Works well for areas with naturally
soft water.
Ozone is a strong oxidizing
biocide that attacks cell walls
pg. 66

Oxidizing Biocides
Sodium Hypochlorite =
NaClO
Bleach: Inexpensive but decomposes
with heat and light.
Solution: On site bleach generator. MIOX ®
Salt (NaCl) + Electricity (via electrolysis) = Bleach
pg. 67

Nonoxidizing
Biocides
Surface Acting
Quaternary ammonium
compounds (quats) are
cationic surface-active
molecules. They damage
the cell walls of bacteria,
fungi, and algae. The cell
“bleeds” and dies.
Metabolism (internal) Acting
Many antimicrobials interfere with energy metabolism inside the cell. The cell gets “sick”
and cannot reproduce. The following are examples of these types of biocides:
organotins
bis(trichloromethyl) sulfone
methylenebis(thiocyanate) (MBT)
Beta-bromo-Beta-nitrostyrene (BNS)
dodecylguanidine salts
bromonitropropanediol (BNPD)
pg. 68

Chillers
History
By using a mixture of alcohol and ether,
Benjamin Franklin, along with John Hadley
of Cambridge, dropped room temperature
down to 7℉.
“From this experiment, one may see the
possibility of freezing a man to death on
a warm summer day.” B.F.
History
Oliver Evans designed the first
vapor air-conditioning machine,
but never made one.
1834
Jacob Perkins, using Evans design, was first to
patented the air conditioner, but never made one.
In 1902, Willis Carrier built
the first working chiller.
1920’s
< 1920’s:
Simple Ice Box
Monitor Top
(compressor on top)
pg. 69

Basic Composition
pg. 70

Psi →
Btus/pound →
pg. 71

Expansion Valve
Thermostatic
Expansion Valve
( = TEV = TXV )
Electric
Expansion
Valve
Orifice Plate
Expansion
Valve
Low Load
High Load
Float
Expansion
Valve
pg. 72

Liquid Line Filter Drier
Refrigerant Oil Filter
pg. 73

Chiller
Economizer
pg. 74

Refrigerants
Refrigerants
It is suspected that a variety of biological
consequences such as increases in sunburn, skin
cancer, cataracts, damage to plants, and reduction of
certain plankton in the ocean may result from the
increased UV-B exposure due to ozone depletion.
Image of the largest Antarctic
ozone hole recorded (September
2006), over the Southern pole.
1920’s Sulfur Dioxide . . . . . . . Corrosive, Toxic
Methyl Formate . . . . . Flammable, Toxic
Ammonia . . . . . . . . . . . Toxic
1930’s Chlorofluorocarbons Ozone Depletion
CFC’s
1960’s Hydrochloroflourocarbons Ozone Depletion
HCFC’s
1990’s Hydrofluorocarbons Safe
HFC’s
CFCs: Banned in US and Canada HCFCs: Being phased out HFCs: OK
pg. 75

Refrigerants (continued)
>>>>CFC refrigerants
CARBON, FLORINE, CHLORINE.
Banned from use or production within all
countries covered by the Montreal
Protocol.
>>>>HCFC refrigerants
HYDROGEN, CARBON, FLORINE, CHLORINE.
Being phased out.
>>>>HFC refrigerants
HYDROGEN, FLORINE, CARBON.
HFC’s contain no chlorine:
NO OZONE DEPLETION.
It is estimated that the Ozone layer will
revert back to its original level by 2050!
pg. 76

ANHYDROUS
= Contains no water
Being Phased Out
Acceptable
Natural Refrigerants:
R717 Ammonia NH 3 BP -28°F
R290 Propane C 3H 8 BP -44°F
R600a Iso-butane C 4H 10 BP 11°F
R600 Butane C 4H 10 BP 31°F
R744 Carbon Dioxide CO 2 BP -109°F
Azeotrope
- A mixture made up of two or more refrigerants
with similar boiling points that act as a single fluid.
The components of azeotropic mixtures will not
separate under normal operating conditions and
can be charged as a vapor or liquid.
Zeotrope
- A mixture made up of two or more refrigerants
with different boiling points which creates a
boiling point “glide”. Therefore: Zeotropic
mixtures should be charged in the liquid state.
pg. 77

Corrosion
MIC
MIC
Microbiologically Induced Corrosion
Biofilm = Slime
Under the slime is an
area where Anerobic
bacteria thrive.
Cathode
←e¯
M +
Anode
e¯→ Cathode
Anaerobic bacteria “eat” metal by means
of reduction reaction.
Its waste is food for the aerobic bacteria in the
slime. These colonies form tubercles.
Aerobic = breaths 0xygen
Anaerobic = does not breath O2
Tubercle grows,
penetrating completely
through metal.
←e¯
↑
M +
e¯→
Upon removing Tubercles,
shiny, raw metal is exposed.
pg. 78

MIC Prevention and control
Water Treatment Biocides + Non-penetrable, Non-metallic Coatings
Fouling prevention and control
Manually “punching ” tubes
Automatically punching tubes
pg. 79

Eddie Current Testing
Cracks, corrosion, or other imperfections
create out of specification signals.
pg. 80

Chiller Compressor Types
Positive Displacement
Reciprocating
Single Acting
Double Acting
pg. 81

Rotary
Single Screw
Double Screw
pg. 82

TXV
Oil separator
Economizer
pg. 83
Auto shut valves

Scroll
Vane
pg. 84

Dynamic
Centrifugal
pg. 85

Because of the high boiling point, lowpressure
chillers evaporate the refrigerant
in vacuum conditions
Beacause of the nature of a vacuum, sometimes non-refrigerant
gas (air) leaks in (is sucked in).
Low Pressure Centrifugal Chiller Purge Unit
Removes and vents non-condensable gases and at the same
time, returns refrigerant as a liquid to chiller condenser.
Compressor
Filter drier
Safety Burst Disc
Pneumatically controlled shutoff valves
pg. 86

Centrifugal:
Magnetic Bearing
Computer controlled lead lag
alternates operating compressor for
even, on-demand use
When the chiller is operated in cooling mode, the
condensed liquid refrigerant exits the electronic
expansion valve (4), and enters the
bottom of the flooded evaporator, where it is
evenly dispersed along the length of the
evaporator by the use of a distributor plate (3).
Liquid refrigerant inside the evaporator at low
pressure then makes contact with the copper
tubes that the building’s water runs through,
exchanges heat to the refrigerant, and vaporizes
it (2) at the suction pressure of the compressor
(1). As a result of the lower density of the vapor
and the suction of the compressor, the vaporized
refrigerant gas is then drawn to the top of the
evaporator through the mist eliminators (5). (Mist
eliminators inhibit minute liquid particles
entrained in the vaporized refrigerant, from
entering the compressor). Passing through the
(pre-rotation) inlet guide vanes (6), the vaporized
refrigerant then enters the compressor inlet (7),
where the angle of incidence of the refrigerant
hitting the first stage impeller, is altered, thereby
allowing a higher compression efficiency for a
given compressor rotor speed.
No lubricating oil needed.
Electronically Controlled TXV
pg. 87

Hermetic and
Semi Hermetic
Hermetic
piston
scroll
Hermetic = air tight, not designed to be opened. Design
helps prevent contamination of edibles.
Semi Hermetic = air tight, but designed to enable access
to inside components.
Semi Hermetic
pg. 88

Absorption Cooling
Ammonia/Hydrogen Refrigeration
Evaporating ammonia cools off,
travels along tube and is reabsorbed
by the water.
COLD
COLD
Hydrogen
Electric Heater Driven
RV Propane Driven
pg. 89

Lithium Bromide (LiBr) Absorption Chillers
Water is used as a
refrigerant. At very low
psi, it will not freeze.
Evaporation chamber is
maintained @
0.24 in. Hg = 0.12 psia.
At this pressure (closely
above the triple point),
water boils at 39°F
producing chilled process
water in the coil.
pg. 90

Free Cooling
When conditions are favorable, significant ∆T can be achieved
and energy is saved by simply bypassing the chiller.
pg. 91

Chiller Chiller Surge Surge
If heat is not removed sufficiently from the condenser, then the
refrigerant will build up pressure resisting the compressor and, in
some extreme cases, flow backwards against the compressor!
Normal flow
Compressor
SURGE: Too high of pressure in condenser,
forces backflow, damaging chiller.
Evaporator
Condenser
high psi
Possible Causes:
Poor water circulation to cooling tower: plugged filters, pump failure
Cooling tower fan failure
Scale and or biological growth build-up in condenser (no heat transfer)
Heavy fouling in cooling tower media (cooled water not being produced)
In some extreme cases, the evaporator has gotten too cold and forms a vacuum
(example: chilled water demand drops suddenly)
Monitor Approach Temperatures
Evaporator Approach is the difference between the evaporating refrigerant temperature, measured at the
well in the evaporator, and leaving chilled water temperature.
Condenser Approach is the difference between the liquid refrigerant temperature, as measured on the
liquid line, and leaving condenser water temperature.
Take all readings with the water cooled chiller at full load.
pg. 92

4 Funtion Valve, 7
4
A
Absolute Zero, 10, 18, 37, 41
Absorption Chiller, 90
Absorption Cooling, 89
AC, 32
Acid, 24
Actuator, 4, 56
Adiabatic Process, 38
Aerobic, 78
Affinity Law, 33
Air Conditioner, 13, 14
Algae, 62
Alkaline, 24
Alternating Current, 32
American Legion, 63
Ammonia, 24
Ammonia/Hydrogen Refrigeration, 89
Amps, 9
Anerobic, 78
Anion, 29
Anode, 59, 60
Antarctica, 39
Antifreeze, 26
Aquastat, 23, 25
Atm, 17
Azeotrope, 77
Back Siphonage, 6
Backflow, 6
Bacteria, 26, 78
Balance Point, 14
Ball Valve, 3
Bar, 12
Barometer, 12
Base, 24
Base Load, 36
Bellevue Stratford Hotel, 63
Benjamin Franklin, 69
BHP, 9
Biocide, 65
Bleach, 65, 67
Boiling Point, 11, 17, 22
Bourdon-Tube, 12
BPHE, 31
Brahmaputra Mountains, 39
Braized Plate, 31
Bromine, 61, 65
BTU, 17, 22
BTU Content, 22
CaCO3, 55
Calcium Carbonate, 55
B
C
Calcium Sulfate, 55
Cambridge, 69
Can pump, 8
Cathode, 59, 60, 61
Cation, 29
Cavitation, 21
Centrifugal Compressor, 85
CFCs, 75, 77
Cherrapunjee, 39
Chiller Surge, 92
Chillers, 69
Chlorine, 61, 65, 76
Closed Recirculating Cooling Tower, 49
Coal, 9
Compound Guage, 12
Compressor, 13
Condensate, 12
Condensation, 10, 18
Conduction, 16
Controllers, 25
Convection, 16
Critical Pressure and Temperature, 22
Cross corrugated, 50
Cross flow, 48
DC, 32
Dead Sea, 11
Dehumidifier, 15
Delta T, 91
Demineralize, 29
Deposition, 18
Dew, 37
Diaphragm feed pump, 7
Dielectric Union, 59
Direct Current, 32
Direct Evaporative Cooling, 40
Double Acting Compressor, 81
Double Screw Compressor, 82
Drift eliminator, 50
Dry bulb, 41, 42
Dry Valleys, 39
Dynamic Compressor, 85
Economizer, 74
Eddie Current, 80
Edison, Thomas, 32
Electrodes, 56
Electrolysis, 67
Electromagnet, 56
Equilibrium, 10, 37
Ethylene Glycol, 26
Evaporation, 10, 18
exothermic, 41
Expansion Valve, 13
Expansion, water to ice, 23
Explosion, 20
D
E

Feed Water Pumps, 8
Fiber reinforced plastic, 47
Film Fill, 51
Filter Drier, 73
Flash Steam, 20
Float Expansion Valve, 72
Food Grade Antifreeze, 26
Foot Valve, 7
Forced draft, 46
Fouling, 50
Free cooling, 91
Freeze Drier, 19
Freeze Point, 26
Fridgidair, 69
Frost, 37
FRP, 47
Fuel Oil, 9
Galvanic corrosion, 59
Galvanized Steel, 49
General Electric, 69
Glide, 77
Glycol, 26
gravel, 21
Grid, 36
Halides, 61
Hamburger Helper, 11
HCFCs, 75, 77
HDPE, 47
Heat Exchanger, 31
Heat Pump, 14
HEDP, 57
Hermetic, 88
Hexagonal, 23
HFCs, 75, 77
High density polyethylene, 47
Hot Air Balloon, 20
Hydrofluorocarbons, 75
Hydrogen, 24
Hydroxide, 24
Hyperbolic, 45
Hypobromous Acid, 65
Hypochlorous Acid, 65
Ideal Gas Law, 13, 20, 28
Immersion heater, 54
Impeller, 21, 85
Induced draft, 47
F
G
H
I
Induction Coil, 80
Intercooler, 13
Iodine, 65
Jacob Perkins, 69
John Hadley, 69
Kiln, 15
Ladder, 52
Lake Tahoe, 11
Latent heat, 44
LEED, 34
Legionella, 63, 64
LiBr, 90
Lithium Bromide Chiller, 90
Low Water Cutoff, 20
Magnetic Bearing Chiller, 87
Melting, 18
Membrane, 30
Mercury Switch, 25
Metabolism, 68
MIC, 78, 79
Mold, 62
Monitor Top, 69
Mono Lake, 57
Mt. Everest, 11
Multistage Pump, 8
Myox, 67
Neutral Water, 24
Nitrites, 26
Non-metallic Coating, 79
J
K
L
M
N
O
Ohms, 9
Oil Filter, 73
Old Faithful, 17
Oliver Evans, 69
Open Recirculating Cooling Tower, 49
Oriface Plate Expansion Valve, 72
ORP, 66
Oxides, 59
Oxidizing, 65
Ozone, 66
pg. 94

Ozone Layer, 75
Parrallel pumps, 8
Pascal, 12
Peristaltic Feed Pump, 7
pH, 24
Phases of Water, 17
Philadelphia, 63
Phosphates, 57
Pickup Coil, 80
Pigtale Loop, 12
Pilot, 35
Plate and Frame, 31
Polyvinylchloride, 47
Precipitation, 39
Pressure vs. Heat Content Chart, 71
Pressure/Temperature Reducing Valve, 28
Pressurestat, 25
Pressuretrol, 25
Priming Valve, 7
Propane Tank, 13
Propeller, 21
Propylene Glycol, 26
psia, 11, 12
psig, 11, 12, 17
Psychrometer, 42
Psychrometric Chart, 41, 43
Punching Tubes, 79
Purge Cycle, 20
PV=nRT, 13
PV=T, 13, 20
PVC, 47
Pyrometer, 27
Quaternary ammonia, 68
Quill, 7
Radiant Heat, 16
Radiation, 16
Reduced Pressure Zone, 6
Refractometer, 26
Refrigeration, 13
Regeneration, 29
Relative Humidity, 41, 42
Resin Beads, 29
Resistance, 9
Restricting Orifice, 28
Reverse Osmosis, 30
Reversing Valve, 14
RH, 42
RO, 30
P
Q
R
Rotary Compressor, 82
Rust, 60, 61
Sand Filter, 55
Saturated Steam, 17
Saturation Curve, 10, 37
Saturation Point, 10, 40, 56
Scale, 57
Scroll Compressor, 84
Sea level, 19
Sea Level, 11, 17, 18, 22
Semi hermetic, 88
Sensible Heat, 16
Series Connection, 9
Series Pumps, 8
Shell and Tube, 31
Side Stream Filter, 55
Silica, 55
sine wave, 32
Single acting compressor, 81
Single phase, 32
Single Screw Compressor, 82
Siphon Loop, 12
Slime, 78
Snap Switch, 25
Sodium Hypochlorite, 67
Solenoid, 4, 56
Sørensen, Søren, 24
Spark Ignitor, 35
Splash fill, 52
Splash guards, 48
Steam Table, 22
Step Down Transformer, 36
Step Up Transformer, 36
Stethoscope, 27
Stroke, 7
Sublimation, 18, 19
Sultana, 20
Supercritical Steam, 22
Superheated Steam, 17
Surge, 92
Termperature Glide, 77
Tesla, Nickola, 32
TEX Valve, 72
Thermal Imager, 27
Thermocouple, 35
Thermopile, 35
Thermowell, 25, 54
Three phase, 32
Tom Thumb, 9
Tonnage, 44
Torque, 33
S
T
pg. 95

Transformer, 36
Transmission, 36
Triple Point, 18, 90
Tubercle, 78
TXV, 72
VFD, 33
Volts, 9
Volute, 85
W
Vacuum, 10, 11, 12, 19
Vacuum Gauge, 12
Vane Compressor, 84
Vanes, 84
Vapor Pressure, 10
Vaporization, 10
Variable Frequency Drive, 33
V-bars, 52
Vertical offset, 50
V
Water hammer, 5
Water level indicator, 53
Watts, 9
Wet bulb, 41, 42
White rust, 60
Willis Carrier, 69
Zeotrope, 77
Z
pg. 96