FUNdamentals of

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Prof. Koldenhotts
FUNdamentals of Cocktailmetrics...
Prof. Koldenhott says, This is a lesson of air
and water vapor in a cocktail (that is, a
mixture) with apologies to Mr. Willis Carrier.
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Your instructor...
Mr. Terry L. Robinson
aka
N.A.T.E. certified
Active Member
Member of Council of Refrigeration and Air
Conditioning Educators
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Cocktailmetrics aka
Psychrometrics
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In the early 1900s, there was a young engineer
Working For Buffalo Forge Company that received
a 'flash of genius' while waiting for a train.
It was a foggy night and he was going over in
his mind the problem of temperature and
humidity control. By the time the train arrived,
Carrier had an understanding of the relationship
between temperature, humidity and dew point.
That young engineer was
Willis H. Carrier from The Father of Cool Willis
Haviland Carrier The History of Air Conditioning
by Mary Bellis on www.about.com
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What Mr. Carriers 'flash of genius' that day
came to be known as Psychrometry...
the study of air and water vapor in mixture.
Its this mixture idea that leads me to nick-
name Psychrometrics, Cocktailmetrics.
says Prof. Koldenhott
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Psychrometric Chart...
graphically shows the Properties of Air.
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Psychrometric Chart used...
to model conditions inside buildings by system
designers.
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Psychrometric Chart used...
to monitor conditions in commercial
refrigeration plants and manufacturing
environments.
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Psychrometric Chart used...
to evaluate problems in air conditioned
environments.
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Structure
H E E L
INSTEP
INSTEP
SOLE
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Seven Properties of Air
7
2
5
4
3
6
1
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Seven Properties of Air...
1. Prof. Koldenhotts Dry Noodle Temp better
known as Dry Bulb Temperature
taken with a standard thermometer.
0F
SOLE
800 F DB
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PROPERTY OF AIR SYMBOL EXPRESSED BY SCALE LOCATION LINE DRAWN
DRY BULB TEMP DB 0F SOLE BOTTOM STRAIGHT UP






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Seven Properties of Air...
2. Prof. Koldenhotts Wet Noodle Temp better
known as Wet Bulb Temperature
taken with a thermometer with a wetted wick.
660 F WB
Instep
SLING PSYCHROMETER
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PROPERTY OF AIR SYMBOL EXPRESSED BY SCALE LOCATION LINE DRAWN
DRY BULB TEMP DB 0F SOLE BOTTOM STRAIGHT UP
WET BULB TEMP WB 0F INSTEP SLANTED





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Seven Properties of Air...
3. Prof. Koldenhotts Wet Spot Temp better known
as Dew Point Temperature
temperatue at which moisture condenses on a
surface.
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PROPERTY OF AIR SYMBOL EXPRESSED BY SCALE LOCATION LINE DRAWN
DRY BULB TEMP DB 0F SOLE BOTTOM STRAIGHT UP
WET BULB TEMP WB 0F INSTEP SLANTED
DEW POINT TEMP DP 0F INSTEP HORIZONTAL TO LEFT




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Seven Properties of Air...
4. Specific Humidity
(aka Absolute Humidity or Humidity Ratio)
amount of water vapor in dry air. Measured in
grains per pound of dry air.
77 gr/lb
Heel
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PROPERTY OF AIR SYMBOL EXPRESSED BY SCALE LOCATION LINE DRAWN
DRY BULB TEMP DB 0F SOLE BOTTOM STRAIGHT UP
WET BULB TEMP WB 0F INSTEP SLANTED
DEW POINT TEMP DP 0F INSTEP HORIZONTAL TO LEFT
SPECIFIC HUMIDITY W GR/LB HEEL RIGHT VERT HORIZONTAL TO RIGHT



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Seven Properties of Air...
5. Relative Humidity
the amount of moisture vapor the air is holding
compared to what it could hold at the same DB
temperature.
Curved Lines
Saturation Point Curve 100 RH
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PROPERTY OF AIR SYMBOL EXPRESSED BY SCALE LOCATION LINE DRAWN
DRY BULB TEMP DB 0F SOLE BOTTOM STRAIGHT UP
WET BULB TEMP WB 0F INSTEP SLANTED
SPECIFIC HUMIDITY W GR/LB HEEL RIGHT VERT HORIZONTAL TO RIGHT
DEW POINT TEMP DP 0F INSTEP HORIZONTAL TO LEFT
RELATIVE HUMIDITY RH RH CURVED CURVED


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Seven Properties of Air...
6. Specific Volume
- Space that one pound of dry air takes up
- Steeply slanted lines
- Expressed in Cubic Feet per Pound ( ft3/lb )
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PROPERTY OF AIR SYMBOL EXPRESSED BY SCALE LOCATION LINE DRAWN
DRY BULB TEMP DB 0F SOLE BOTTOM STRAIGHT UP
WET BULB TEMP WB 0F INSTEP SLANTED
SPECIFIC HUMIDITY W GR/LB HEEL RIGHT VERT HORIZONTAL TO RIGHT
DEW POINT TEMP DP 0F INSTEP HORIZONTAL TO LEFT
RELATIVE HUMIDITY RH RH CURVED CURVED
SPECIFIC VOLUME V FT3/LB STEEPLY SLANTED STEEPLY SLANTED

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Seven Properties of Air...
7. Enthalpy
- Total amount of heat energy (sensible and
latent) in one pound of air.
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PROPERTY OF AIR SYMBOL EXPRESSED BY SCALE LOCATION LINE DRAWN
DRY BULB TEMP DB 0F SOLE BOTTOM STRAIGHT UP
WET BULB TEMP WB 0F INSTEP SLANTED
SPECIFIC HUMIDITY W GR/LB HEEL RIGHT VERT HORIZONTAL TO RIGHT
DEW POINT TEMP DP 0F INSTEP HORIZONTAL TO LEFT
RELATIVE HUMIDITY RH RH CURVED CURVED
SPECIFIC VOLUME V FT3/LB STEEPLY SLANTED STEEPLY SLANTED
ENTHALPY H BTU/LB ABOVE INSTEP EXTENSION OF WB LINE
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PSYCHROMETRIC ASSIGNMENT

• Prof. Koldenhott suggests that you do the
  following Assignment
• Print multiple copies of the next slide
  (Psychrometric Chart.)
• Using a Sling Psychrometer, record Outdoor
  Conditions and Indoor Conditions. (Note
  Instruction on how to construct a sling
  psychrometer follows the next slide.)
• Plot the Outdoor conditions (DB and WB) on one
  Psychrometric Chart.
• Plot the Indoor conditions (DB and WB) on one
  Psychrometric Chart.
• Draw the lines necessary to find all other
  Properties of air

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DB TEMP_______ NOTE USE PROPER UNITS. WB
TEMP______ DP TEMP______ W_________ RH________
V_________ H_________
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Making a Sling Psychrometer for reading WB
Need 1 ea. Athletic Shoe Lace
Cut Shoe Lace
X
Poke Pocket Thermometer into long piece of Shoe
Lace
To use Wet short end and sling while
holding on to long end.
Short piece taped or rubber-banded to Thermometer
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Air Conditioning Processes
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Air Conditioning Processes...
Transition
Evap Coil
Blower Section
Return Air Plenum
Supply Air Plenum
Heat Section
Psychrometric changes take place between RA and SA
SA
RA
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Heating only
Sensible change
Process Line moves horizonally to right
0DGR
Initial Point
(Return Air reading)
DT
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Cooling only
Sensible change
Process Line moves horizonally to left
0DGR
DT
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Humidifying only
Process Line moves straight up
DGR
Latent change
0DT
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Dehumidifying only
Process Line moves straight down
Latent change
DGR
0DT
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Other AC Processes...
Sensible and Latent change
Heating Humidifying
Cooling Humidifying
Cooling Dehumidifying
Heating Dehumidifying
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What we need for evaluating AC Processes...
DH
RA
50 RH
Process Line
DGR
SA
80 RH
800 F DB
600 F DB
DT
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Air Side Equations
Sensible Load Qs 1.1 X CFM X DT
A constant based on the Density of Air and a time
conversion factor
Determined from the Condensing Unit model number
QS is expressed in BTUH
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Air Side Equations
Latent Load QL .68 X CFM X DGR
A constant including a time conversion factor
Same as that used for QS
QL is expressed in BTUH
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Air Side Equations
Total Load QT 4.45 X CFM X DH
A constant including a time conversion factor
Same as that used for QS
QT is expressed in BTUH
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PSYCHROMETRIC PROCESSES ASSIGNMENT

• Prof. Koldenhott suggests that you do the
  following Assignment
• Using a Sling Psychrometer, record Return Air
  Condition and Supply Air Condition of an actual
  Air Conditioning Process (suggest Cooling and
  Dehumidification for best results.) Determine CFM
  from Model of Outdoor Unit. Plot the RA and SA
  on the chart.
• Draw the Process Line. What type of
  Psychrometric Process?____________________________
  __
• Determine DT______, DGR______DH_______
• Calculate
• a. QS________________
• b. QL________________
• c. QT________________

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Sensible Heat Ratio
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Sensible Heat Ratio
LATENT
SENSIBLE
the ratio of Sensible Load (QS) to
Total Load (QT)
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Sensible Heat Ratio
SHR
QS
QT
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Sensible Heat Ratio
Example
29,060 btuh

SHR
36,325 btuh
.80 SHR
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Sensible Heat Ratio
The way Engineers Plot SHR on the Psychrometric
Chart
Permanent Index Point
.80 SHR
.
Note Any Process Line parallel to this line will
maintain the SHR
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SENSIBLE HEAT RATIO ASSIGNMENT
Prof. Koldenhott suggests that you do the
following Assignment Calculate Actual Sensible
Heat Ratio for the previous assignment.
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Sensible Latent Changes in Enthalpy
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Latent change in Enthalpy
HL
Hs
Sensible change in Enthalpy
DGR Latent change
DT Sensible change
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If youve gone through the entire presentation, I
appreciate your effort. Please let me know what
you think.
Email profkoldenhott_at_tx.rr.com or write Prof.
Koldenhott 2787 Sun Valley
Dr. Grand Prairie, Texas 75052