Keeprite KWH Installation Manual
PRODUCT DATA &
INSTALLATION
Bulletin K70-KWS-PDI-11
1064614
Water Cooling
Coils
Type KWS Single Serpentine
Type KWH Half serpentine
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Water Cooling Coils ........................................2
General Specifications ....................................3
Type KWS Coil................................................4
Nomenclature..................................................4
Type KWH and KWD Water Coils...................5
General Formulas ...........................................6
Wet Bulb Depression Ratio.............................6
System Design ................................................7
Coil Selection - Sizes - Table 1 .......................7
Coil Selection - Fin Series Capacity
Correction Factors - Table 2....................8
Coil Selection - General Considerations .........8
Conversion of Air Volume to St andard Air .......9
Total Heat - Table 3........................................10
Explanation for Using Direct
Selection Tables..............................11, 12
Direct Selection - Table 4 .....................13 to 21
Example Coil Selection No. 1 ........................22
Example Coil Selection No. 2 ...................23,24
Mean Effective Temperature
Difference -Table 5 ................................25
Type KWD Double Serpentine
NOMENCLATURE
TYPE MODEL FACE DIMENSIONS
KW
Coil Type
CIRCUITING:
S = Single Serpentine
D = Double Serpentine
H = Half Serpentine
Fin Series (70, 80, 100
or 120) (100 shown)
Rows Deep
“W” Dimensions (inches)
Nominal Tube Length (inches)
CONTENTS
Standard Coil Circuiting - Table 6 ..................26
Wetted Surface Factor - Figure 3..................26
Heat Transfer Coef ficient - Figure 4 .............. 27
Fin Correction - Table 7 .................................27
Wet Bulb Depression Factors.......................28
Air Pressure Drop - Figure 6 ......................... 29
Air Friction Fin Series Correction
Factors -Table 8 ....................................29
Air Friction Sample Calculation
Example No.3........................................ 29
Water Pressure Drop Curve - Figure 7 .........30
Water Pressure Drop Correction Factors
and Example Problems......................... 31
Water Pressure Drop Coil Type - Table 9...... 31
Dimensional Drawings ..................................32
Application Recommendations ..................... 33
Pipe Size Selection Chart - Figure 1 1 ..........33
Psychrometric Functions ..............................34
Psychrometric Chart - Figure 16...................35
Engineering Specifications............................36
S
D
H
- 1 0 5 - 18 x 45
Water Cooling Coils
MECHANICAL
PRESSURE BOND
KeepRite Mechanical
Pressure Bond guarantees
that each tube and fin collar
make positive permanent
metal to metal contact.
No need for using low
conductivity metals or alloys,
FLANGED CASINGS
Double flanged galvanized
steel casings on all
KeepRite Water Heating
Coils provide greater
strength - better support
for easier coil stacking.
Simplifies moving and handling operations.
Top and bottom casing flanges are turned back to
form two channel sections in a “box shape”.
Provides maximum strength and durability.
COPPER TUBE HEADERS
Made from heavy gauge seamless drawn copper
tube, KeepRite designed headers lengthen coil life
- provide necessary header flexibility to
compansate for expansion and contraction during
operation.
Header flexibility also reduces coil core “strains”
during start up. Further proof that KeepRite
design means long life and top performance.
FULL FIN
COLLARS
Efficient KeepRite
fin presses perform
multi - stage operations
to draw full fin collars
with wide, smooth surfaces
that completely cover coil
tubes - actually form a tube within a tube for
greater strength and maximum heat transfer.
Lack of sharp collar edges make KeepRite
Coils easier to clean - smoother KeepRite
Collars retard lint and dirt accumulation.
- 2 -
AVAILABLE IN FOUR STANDARD
FIN SPACING
GENERAL
SPECIFICATIONS
70 FIN SERIES is designed and used for applications re-
quiring high latent loads and for installations requiring low
air pressure drop. With the 70 Fin Series Coil, it is possible to more accurately match sensible and total loads,
particularly when the water temperature is low and the
entering wet bulb air temperature is high.
80 FIN SERIES has been more or less a standard in the
industry for 15 to 20 years. This fin series and the 100 Fin
Series surface are widely used for regular
commercial applications because the S/T ratios achieved
with these surfaces meet the normal S/T ratio
requirements.
When only the 80 Fin Series Coil surface was available,
frequently more rows of coil were required to meet either a
total or sensible load than is now required with 100 and
120 Fin Series Coils. When extra rows are furnished to
meet either a sensible or total requirement, the
excessive capacity furnished can result in something less
than ideal conditions in the conditioned space.
100 FIN SERIES introduced approximately ten years ago
by KeepRite has been furnished for special industrial
applications that require higher than normal sensible
cooling loads. Experience has shown this is an excellent
heat transfer surface, not only for high sensible load
requirements, but also for average S/T ratio jobs, when
space will not permit larger face areas and/or more rows
to be installed and capacity requirements exceed the
capabilities of 80 Fin Series Coils.
The increase in air friction that results by changing from
an 80 Fin Series to a 100 Fin Series with shallow depth
coils is usually less than the increase in air friction if one
additional row of 80 Fin Series Coil is utilized.
PRIMARY SURFACE - 5/8" O.D. round copper
tubes on 11/2" equilateral centers.
SECONDARY SURFACE-Rippled aluminum or copper, die
formed plate type fins. Fin collars are full drawn to provide
accurate control of fin spacing and to completely cover the
tube for maximum heat transfer.
HEADERS-Extra heavy seamless copper tubing. Tube
holes provide flexibility for uneven stresses and the
maximum brazing surface possible.
CONNECTIONS-Male pipe supply and return
connections.
BRAZING-All core joints are brazed with copper
brazing alloys.
CASING-Die formed heavy gauge continuous galvanized
steel with reinforced mounting flanges. Fin angles
completely brace the core assembly in the casing of all
large coils to prevent air by-pass and damage in shipment.
VENTS AND DRAINS-Furnished on all coils.
TESTS - Complete coil tested leak free at 300 PSIG
air pressure under water.
120 FIN SERIES was designed as a maximum capacity
surface with reasonable air pressure drop and is
particularly suitable for use in commercial and industrial
installations requiring higher than average sensible total
ratios.
The 120 Fin Series heat transfer surface offers the
maximum BTU capacity per dollar invested for
applications where this surface is suitable. The 120 Fin
Series provides the maximum amount of total external
surface per sq. ft. of face area per row deep that is
practical without encountering excessive air pressure
drops.
OPERATING CONDITIONS-Standard coils are suitable for
use up to 200 PSIG.
- 3 -
WATER COOLING COILS
TYPE “KWS” COILS
Type “KWS” Coils are specifically designed and
engineered to meet most applications requiring normal
water quantities and normal water pressure drop.
Type “KWS” Coils are counterflow, single serpentine
circuited to deliver absolute maximum performance.
With single serpentine coils every tube in the first row is
fed as indicated in the circuiting drawing on the right.
Type “KWS” Coils of two, four, six, eight and ten rows
deep are furnished with the supply and return connections on the same and of the coil.
TYPE “KWD” COILS
Type “KWD” Coils are designed for use in applications
that require high water quantities and low water pressure
drop.
“KWD” Coils are counterflow, double serpentine circuited
to maintain normal water velocities and low water
pressure drops. With double serpentine coils every tube in
the first and second rows are fed as shown in the
circuiting drawing on the eright.
AIR FLOW
6 ROW KWS CIRCUITING
HORIZONTAL OR VERTICAL AIR FLOW
AIR FLOW
Fourn and eight row coils have the supply and return
connections on the same end of the coil.
TYPE “KWH” COILS
Type “KWH” Coils are designed to produce high
capacity with limited water quantity. High capacity is
obtained from the counterflow half serpentine water
circuiting which gives higher water velocities.
With half serpentine coils every other tube in the first
row is fed as shown in the circuiting drawing on the
right.
All Type “KWH” Coils, regardless of row depth, have
both the supply and return connections on the same end
of the coil. When ordering KWH Coils, state vertical or
horizontal air flow as required.
8 ROW KWD CIRCUITING
HORIZONTAL OR VERTICAL AIR FLOW
AIR FLOW
4 ROW KWH CIRCUITING
HORIZONTAL AIR FLOW
- 4 -
GENERAL INFORMATION
1. TOTAL BTU/HR
Total BTU/HR = 4.5 x CFM X (Total Heat Ent. Air - Total
Heat Lv. Air)
Where 4.5 = Density Std. Air x 60
Density Std. Air = .075 lbs./Cu. Ft.
Minutes/hr. = 60
5. WATER VELOCITY
1.144* x GPM
Water Velocity FPS =
*Use 1.326 for high pressure coils
Use 1.35 for .049 tube wall.
Number tubes fed
2. TOTAL BTU/HR
Total BTU/HR = 500 X GPM X (Lv. Water Temp. - Ent.
Water Temp.)
Where 500 = Lbs./Gal. X Min./Hr. X Specific Heat Water
Lbs./Gal. = 8.33
Min./Hr. = 60
Sp. Heat Water = 1
3. SENSIBLE BTU/HR
Sensible BTU/HR = 1.09 X CFM X (Ent. Air D.B. - Lv.
Air D.B.)
Where 1.09 = (sp. Ht. of air at 70°F.) X (Minutes/Hr.)
X Density Std. Air
Sp. Ht. of Air = .24 at 70°F.
Min./Hr. = 60
Density Std. Air = .075 Lbs./Cu. Ft.
4. LEAVING AIR DRY BULB TEMPERATURE
(a) Lv. Air D.B. = Ent. Air D.B. =
(b) Ly. Air D.B. = Lv. W.B. + (W.B. Depression Factor
X Initial W.B. Depression)
(c) Lv. Air D.B. = Lv. W.B. + Final W.B. Depression
Sens. BTU/HR
1.09 X CFM
Total BTU/HR
6. ROWS DEEP =
Where WSF = Wetted Surface Factor (From Figure 3 , Page 26)
MED = Log Mean Temperature Difference (From Table 5,
Page 24)
F
= Fin Series Correction Factor (From Table 7, Page 27
FR
Face Area. ( Sq. Ft.) x WSF x Med. x U x F
7. FACE AREA
F.A. =
CFM
Face Velocity (FPM)
8. FACE VELOCITY
F.V. =
CFM
Face Area (Sq. Ft.)
9. SENSIBLE TOTAL RATIO
S/T Ratio =
Sensible BTU/HR
Total BTU/-HR
10. TONS PER SQUARE FOOT OF FACE AREA
Tons/Sq. Ft. =
Total BTU/HR
Face Area (Sq. Ft.) X 12000
11. INITIAL W.B. DEPRESSION
Initial W.B. Depression = Entering D. B.- Entering W.B.
12. FINAL W.B. DEPRESSION
Final W.B. Depression = leaving D.B. - leaving W.B.
FR
WET BULB DEPRESSION RATIO
Since both sensible and latent heat transfer are occurring
simultaneously between the surface of a chilled water
dehumidifying coil and the air passing over it, some coil
performance factor which establishes the relationship
between these two modes of heat transfer is required. For
this purpose KeepRite employs the wet bulb depression
factor which has the general acceptance of the finned tube
coil industry.
The wet bulb depression factor is the ratio of the leaving air
to entering air wet bulb depressions and is expressed as
follows:
Wet Bulb Depression
Factor (WBDF) =
Temp.
Temp.
For the example illustrated below, the Wet Bulb
Depression Factor Is:
WBDF =
80°F - 67°F = 13
61°F - 58°F 3
Since the wet bulb depression factor describes a heat
transfer relationship on the fin side of a coil only, it varies
with the air side heat transfer performance, the amount of
heat transfer surface and with the air velocity.The WB
depression factor is determined by laboratory tests of each
particular coil surface design. It should be noted that it is
Leaving Wet Bulb Depression
Entering Wet Bulb Depression
Lvg. Air D.B. - Lvg. Air W.B.
=
Ent. Air D.B. - Ent. Air W.B.
= .231
- 5 -
not influenced by the water flow rate. The wet bulb
depression factor does not apply to dry surface cooling
coils and is recommended for application only where the
sensible to total heat ratio is 0.9 or less. When the
sensible to total ratio is greater than 0.9, the fin surface
is essentially dry and the coil selection can be based on
dry surface to handle the total load.
Curves giving the wet bulb depression factors for
KeepRite Water Cooling Coils are shown on page 27.
SATURATION CURVE
ENTERING
67°F WET BULB
TEMP.
LEAVING
58°F WET BULB
TEMP.
LEAVING
DEPRESSION
W.B.
58 61 67 80
TEMPERATURE °F
AIR CONDITION
LEAVING COIL
AIR CONDITION
ENTERING COIL
ENTERING W.B.
DEPRESSION
SYSTEM DESIGN AIR QUANITY DETERMINATION
In determining the CFM to circulate, the consulting
engineer normally considers: the volume of the conditioned
space, type of occupance or usage of the space, total load,
3. CFM for total load
CFM =
(4.5) (Enthalpy Ent. - Enthalpy Lvg.)
Total load
sensible load, ventilation requirements, air velocity in the
space (perceptability of air movement) and the sizes of
4. Air changes per hour (from A.S.H.R.A.E. Guide)
ducts required. Usually several of these factors affect the
determination of the CFM to be circulated; however, any
one factor may be controlling.
After determining the controlling factor or factors, the CFM
can be determined by any of the following methods or by
5. Ventilation requirements (from A.S.H.R.A.E.
Guide)
6. Fixed diffusion temperature (Ent. D.B - Lvg. D.B.)
(Usually 15° to 25°F.)
taking a compromise value between results obtained by
several of these methods.
1. CFM per ton (usually 400)
2. CFM for sensible load
CFM =
Sensible load (internal)
1.09 x (Ent. D.B. - lv. D.B.)
Although both total and sensible loads must be
considered in the final analysis, general practice is to
consider only the internal sensible load. Unless a
process is involved, usually the leaving dry bulb
temperature must be assumed and this is normally done
by actually assuming a diffusion temperature.
COIL SELECTION
SIZES
TABLE 1 - COIL SIZES - NOMINAL FACE AREA IN SQ. FT.
"W"
INCHES
12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78
6 .50 .62 .75 .87 1.00 1.13 1.25 1.38 1.50 1.63 1.75 1.88 2.0 2.1 2.2 2.4 2.5 2.6 2.7 2.9 3.0
9 .75 .94 1.12 1.31 1.50 1.69 1.87 2.06 2.25 2.44 2.62 2.81 3.0 3.2 3.4 3.6 3.7 3.9 4.1 4.3 4.5
12 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0 6.3 6.5
15 1.56 1.87 2.19 2.50 2.81 3.12 3.44 3.75 4.06 4.37 4.68 5.0 5.3 5.6 5.9 6.2 6.6 6.9 7.2 7.5 7.8 8.1
18
2.25 2.62 3.00 3.37 3.75 4.12 4.50 4.87 5.25 5.62 6.0 6.4 6.7 7.1 7.5 7.9 8.2 8.6 9.0 9.4 9.7
21 3.06 3.50 3.94 4.37 4.82 5.25 5.69 6.12 6.56 7.0 7.4 7.9 8.3 8.7 9.2 9.6 10.1 10.5 10.9 11.4
24
4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0
27 5.06 5.62 6.19 6.75 7.32 7.87 8.44 9.0 9.6 10.1 10.7 11.2 11.8 12.4 12.9 13.5 14.1 14.6
30 6.25 6.88 7.50 8.12 8.75 9.37 10.0 10.6 11.2 11.9 12.5 13.1 13.7 14.4 15.0 15.6 16.2
33 7.56 8.25 8.94 9.62 10.30 11.0 11.7 12.4 13.1 13.7 14.4 15.1 15.8 16.5 17.2 17.9
36 9.00 9.75 10.50 11.20 12.0 12.7 13.5 14.2 15.0 15.7 16.5 17.2 18.0 18.7 19.5
NOMINAL TUBE LENGTH - NTL - (INCHES)
"W"
INCHES
In addition to the Finned Lengths listed above, KeepRite Refrigeration can furnish coils having any Finned Length
required up to 144 inches.
81 84 87 90 93 96 99 102 105 108 111 114 117 120 123 126 129 132 135 138 141 144
12 6.8 7.0 7.3 7.5 7.8 8.0 8.3 8.5 8.8 9.0 9.3 9.5 9.8 10.0
15 8.4 8.7 9.1 9.4 9.7 10.0 10.3 10.6 10.9 11.2 11.6 11.9 12.2 12.5
18 10.1 10.5 10.9 11.2 11.6 12.0 12.4 12.7 13.1 13.5 13.9 14.2 14.6 15.0 15.4 15.8
21 11.8 12.2 12.7 13.1 13.6 14.0 14.4 14.9 15.3 15.7 16.2 16.6 17.1 17.5 17.9 18.4 18.8 19.3
24 13.5 14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0 20.5 21.0 21.5 22.0 22.5 23.0 23.5 24.0
27 15.2 15.7 16.3 16.9 17.4 18.0 18.6 19.1 19.7 20.2 20.8 21.4 21.9 22.5 23.1 23.6 24.2 24.8 25.3 25.9 26.4 27.0
30 16.9 17.5 18.1 18.7 19.3 20.0 20.6 21.2 21.9 22.5 23.1 23.7 24.4 25.0 25.6 26.2 26.9 27.5 28.1 28.8 29.4 30.0
33 18.6 19.2 19.7 20.6 21.3 22.0 22.7 23.4 24.0 24.7 25.4 26.1 26.8 27.5 28.2 28.9 29.6 30.2 30.9 31.6 32.3 33.0
36 20.2 21.0 21.8 22.5 23.2 24.0 24.7 25.5 26.2 27.0 27.7 28.5 29.2 30.0 30.7 31.5 32.2 33.0 33.7 34.5 35.2 36.0
- 6 -
COIL SELECTION
FIN SERIES CAPACITY CORRECTION FACTORS
TABLE No. 2 F
FD
ROWS
DEEP
4
6
8
For use with tons per sq. ft. from Direct Selection Table No. 4
70 80 100 120
.89
.91
.92
1.00
1.00
1.00
GENERAL CONSIDERATIONS
The cooling process should always be plotted on a
Psychrometric Chart (Page 34) to be sure that the desired
psychromatic changes are feasible.
When selecting a coil it should be remembered that if the
required leaving wet bulb temperature is met, the total load
is satisfied and vice versa. Also, when the required
leaving dry bulb temperature is met, the sensible load
requirement is satisfied.
A coil must meet both the total and sensible load
requirement in order to achieve the conditions desired in the
space to be cooled. Normally the total load capacity is
checked first, however, the leaving dry bulb should always
be checked. When the sensible total ratio is low, the coil
selection is normally controlled by the total load even though
the sensible cooling capacity may exceed the requirement.
In some cases if the leaving dry bulb temperature is too low,
re-heat may be required.
When the S/T ratio is high the coil selection is normally
controlled by the sensible cooling even though the total capacity may exceed that required by an appreciable amount.
If the total capacity far exceeds the requirement, a re-check
on the system should be made to be sure
sufficient system capacity is available.
MATCHING SENSIBLE-LATENT REQUIREMENTS
To more accurately meet sensible and total loads, 70 and
80 Fin Series Coils are recommended for lower S,/T ratios,
and 100 and 120 Fin Series for higher S/T ratios. For
normal S/T ratios, Fin Series 80 and 100 are recommended.
Normal cooling coil face velocities are from 400 to 600 FPM.
500 FPM is recommended for most applications. Moisture
carry-over tends to become a problem when face
velocities in excess of 600 FPM are used unless dry
FIN SERIES
1.12
1.09
1.07
1.22
1.17
1.13
cooling occurs or special consideration is given in
advance to moisture elimination. KeepRite Rippled Fin
Coils of any standard fin series when properly installed
and operated in the normal range, will not require
eliminator plates.
Water cooling coils are normally selected to have a tube
length of three to four times the header height for economy
in coil and duct costs. Coils of several different face
dimensions are usually available from Table 1 page 6 to
meet the required face area. Select the most desirable.
Water velocity in the tubes of approximately 3 to 4 FPS is
desirable to attain high heat transfer rates with a
reasonable water pressure drop.
Cooling coils should not normally exceed 36 inches high
(“W” dimension) as the condensate draining from the top
portion of the coil tends to load up on the lower portion of
the coil. On high latent loads a significant reduction in air
flow and performance may result. Where “W” dimension
exceeds 36" we recommend two or more coils banked
one above the other and installed in accordance with the
recommendations shown on page 32.
In general, the capacity of a Type KWH (half serpentine)
Coil is higher than a Type KWS (single serpentine) for the
same entering air and water conditions because of higher
water velocity. However, the water pressure drop is higher.
The capacity of a Type KWD (double serpentine) Coil is
lower than a Type KWS for the same entering air and water conditions because of lower water velocity.
However, the water pressure drop is lower.
When a coil has a high S /T Ratio, .9 or above, the coil
should be considered dry and selected as a dry coil.
- 7 -
CONVERSION OF AIR VOLUME TO STANDARD AIR
FIGURE 1 - TEMPERATURE CONVERSION FACTOR
1.30
1.25
)
1
TEMPERATURE CONVERSION FACTOR (F
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
-50 -25 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350
1.30
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
TEMPERATURE °F
When the specified air volume (CFM) is given at any temperature other than 70 °F or at any altitude other than sea level, these charts should be
used for correction before using the following capacity and friction tables (which are based on CFM @ standard air conditions).
FIGURE 2 - ALTITUDE CONVERSION FACTOR
1.025
1.000
)
0.975
2
0.950
0.925
0.900
0.875
0.850
0.825
0.800
0.775
TEMPERATURE CONVERSION FACTOR (F
0.750
0.725
0.700
-500 0 500 1500 2500 3500 4500 5500 6500 7500 8500
ALTITUDE (FEET ABOVE SEA LEVEL)
1.025
1.000
0.975
0.950
0.925
0.900
0.875
0.850
0.825
0.800
0.775
0.750
0.725
0.700
Example: To convert 15,900 CFM of air at 94 °F and at 3,000
ft. altitude to standard conditions:
CFM of Std. Air
= CFM of specified Air x F1 x F
2
= 15,900 X 955 X .896 = 13,600
Where: F1 = Temperature conversion factor from Fig. 1.
F2 = Altitude conversion factor from Fig. 2.
- 8 -
TOTAL HEAT
(Enthalpy)
TABLE No. 3 - BTU CONTENT OF 1 LB. OF DRY AIR WITH WATER VAPOR TO SATURATE IT†
(Standard Atmospheric Pressure 29.921” HG.)
WET
BULB
°F. *
35
36
37
38
39
.0 .1 .2 .3 .4 .5 .6 .7 .8 .9
13.01
13.44
13.87
14.32
14.77
13.05
13.48
13.92
14.36
14.82
13.09
13.52
13.96
14.41
14.86
13.14
13.57
14.01
14.45
14.91
TENTHS OF DEGREES
13.18
13.61
14.05
14.50
14.95
13.22
13.66
14.10
14.54
15.00
13.27
13.70
14.14
14.59
15.05
13.31
13.74
14.19
14.63
15.09
13.35
13.79
14.23
14.68
15.14
13.39
13.83
14.27
14.73
15.18
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
15.23
15.70
16.17
16.66
17.15
17.65
18.16
18.68
19.21
19.75
20.30
20.86
21.44
22.02
22.61
23.22
23.84
24.48
25.12
25.78
26.46
27.15
27.85
28.57
29.31
30.06
30.83
31.62
32.42
33.25
15.28
15.74
16.22
16.71
17.20
17.70
18.21
18.73
19.26
19.81
20.36
20.92
21.49
22.08
22.68
23.28
23.90
24.54
25.19
25.85
26.53
27.22
27.92
28.64
29.38
30.14
30.91
31.70
32.50
33.33
15.32
15.79
16.27
16.75
17.25
17.75
18.26
18.79
19.32
19.86
20.41
20.98
21.55
22.14
22.74
23.34
23.97
24.61
25.25
25.92
26.60
27.29
27.99
28.72
29.46
30.21
30.99
31.78
32.59
33.42
15.37
15.84
16.32
16.80
17.30
17.80
18.32
18.84
19.37
19.92
20.47
21.03
21.61
22.20
22.80
23.41
24.03
24.67
25.32
25.98
26.67
27.36
28.07
28.79
29.53
30.29
31.07
31.86
32.67
33.50
15.42
15.89
16.37
16.85
17.35
17.85
18.37
18.89
19.43
19.97
20.52
21.09
21.67
22.26
22.86
23.47
24.10
24.74
25.38
26.05
26.74
27.43
28.14
28.87
29.61
30.37
31.15
31.94
32.75
33.59
15.46
15.93
16.41
16.90
17.40
17.91
18.42
18.95
19.48
20.03
20.58
21.15
21.73
22.32
22.92
23.53
24.16
24.80
25.45
26.12
26.80
27.50
28.21
28.94
29.68
30.44
31.22
32.02
32.83
33.67
15.51
15.98
16.46
16.95
17.45
17.96
18.47
19.00
19.53
20.08
20.64
21.21
21.79
22.38
22.98
23.59
24.22
24.86
25.52
26.19
26.87
27.57
28.28
29.01
29.76
30.52
31.30
32.10
32.92
33.75
15.56
16.03
16.51
17.00
17.50
18.01
18.52
19.05
19.59
20.14
20.69
21.26
21.84
22.44
23.04
23.65
24.29
24.93
25.58
26.26
26.94
27.64
28.35
29.09
29.83
30.60
31.38
32.18
33.00
33.84
15.60
16.08
16.56
17.05
17.55
18.06
18.58
19.10
19.64
20.19
20.75
21.32
21.90
22.50
23.10
23.72
24.35
24.99
25.65
26.32
27.01
27.71
28.43
29.16
29.91
30.68
31.46
32.26
33.08
33.92
15.65
16.12
16.61
17.10
17.60
18.11
18.63
19.16
19.70
20.25
20.81
21.38
21.96
22.56
23.16
23.78
24.42
25.06
25.71
26.39
27.08
27.78
28.50
29.24
29.98
30.75
31.54
32.34
33.17
34.00
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
34.09
34.95
35.83
36.74
37.66
38.61
39.57
40.57
41.58
42.62
43.69
44.78
45.90
47.04
48.22
49.43
34.18
35.04
35.92
36.83
37.75
38.71
39.67
40.67
41.68
42.73
43.80
44.89
46.01
47.16
48.34
49.55
34.26
35.13
36.01
36.92
37.85
38.80
39.77
40.77
41.79
42.83
43.91
45.00
46.13
47.28
48.46
49.68
34.35
35.21
36.10
37.02
37.94
38.90
39.87
40.87
41.89
42.94
44.02
45.12
46.24
47.39
48.58
49.80
34.43
35.30
36.19
37.11
38.04
39.00
39.98
40.97
42.00
43.05
44.13
45.23
46.36
47.51
48.70
49.92
34.52
35.39
36.28
37.20
38.13
39.09
40.07
41.07
42.10
43.15
44.23
45.34
46.47
47.63
48.82
50.04
34.61
35.48
36.38
37.29
38.23
39.19
40.17
41.18
42.20
43.26
44.34
45.45
46.58
47.75
48.95
50.17
34.69
35.57
36.47
37.38
38.32
39.28
40.27
41.28
42.31
43.37
44.45
45.56
46.70
47.87
49.07
50.29
34.79
35.65
36.56
37.48
38.42
39.38
40.37
41.38
42.41
43.48
44.56
45.68
46.81
47.98
49.19
50.41
34.86
35.74
36.65
37.57
38.51
39.47
40.47
41.48
42.52
43.58
44.67
45.79
46.93
48.10
49.31
50.54
* Use wet bulb temperature only in determining total heat. † Compiled from data in ASHRAE GUIDE for 1967
- 9 -
EXPLANATION FOR USING DIRECT SELECTION TABLES
I. PREFACE TO DIRECT SELECTION TABLE NO. 4
Direct Selection Table No. 4 contains a complete and
accurate compilation of data arranged for quick, easy
selection of water cooling coils to prepare or-meet a
specification.
The table covers the conditions normally encountered
in the air conditioning range for 80 Fin Series Coils.
Correction factors for Fin Series 70 100 and 120 are
shown in Table No. 2, page 7.
In many cases a slight adjustment in the CFM, face
area, water temperature rise, or percentage of fresh
air introduced can materially reduce the time required
to select a coil or group of coils.
Since Type KWS (single serpentine) Coils meet most
requirements, the majority of values shown in the
tables are for this coil type.
The color coil circuiting key for the Direct Selection
Tables is as follows: blue-half serpentine; white-single
serpentine; grey double serpentine.
See Dimensional Drawings, page 31 for complete coil
details.
Ill. LIMITATIONS OF CATALOG
1. All information contained in this catalog is based
on water as the cooling fluid. For fluids other
than water consult KeepRite Refrigeration.
2. Direct Selection Table No. 4 is based on 80 Fin
Series Coils. Applicable correction factors for 70,
100, and 120 Fin Series Coils are shown on
Table No. 2, page 7.
3. Interpolation between tables.
a. Interpolation between leaving wet bulb
temperatures should not be attempted as the
result will not be accurate.
b. Interpolation for performance values of Type
KWS, KWH and KWD is not possible, since
water velocities are vastly different. The
different type coils are indicated in the tables
by blue, grey and white.
c. Interpolation for 5 and 7 rows is permissible.
In preparing Direct Selection Tables, the use of
average correction factors has been avoided to
prevent multiplying of errors which could result in poor
coil selection. These tables could be within normally
accepted test laboratory accuracy.
II. VARIABLES COVERED IN DIRECT SELECTION
TABLE NO. 4
1. Values shown in Table No. 4 are for 80 Fin Series
Coils.
2. Entering wet bulb temperatures from 64°F through
70°F in 3°F increments.
3. Face velocities from 400 ft. per min. through 600
ft. per min. in 25 ft. per min. increments.
4. Entering water temperatures of 40, 45 and 50°F.
5. Water temperature rises of 8 and 10°F.
6. Finned lengths from 24" through 120" in 12"
increments.
d. Interpolation for entering water temperatures is
permissible.
e. Interpolation between water temperature rises
of 8 and 10 degrees is permissible.
f. Interpolation between entering wet bulb
temperature is permissible.
g. Interpolation between face velocities is
permissible.
h. Interpolation between finned length is
permissible.
i. Leaving wet bulb temperatures for other than 80
Fin Series Coils must be calculated.
4. Where use of Direct Selection Table No. 4 is not
possible the coil size may be calculated as shown
in Example Problems No. 1 and 2 on pages, 21,
22 and 23.
7. Row detpths of 4, 6, and 8.
8. Capacity in terms of tons per sq. ft. and leaving wet
bulb temperature.
5. Direct Selection Table No. 4 may not be used
when S/ T ratio is .90 or greater.
- 10 -
EXPLANATION FOR USING DIRECT SELECTION TABLES
IV. USE OF DIRECT SELECTION TABLE NO.4
To determine row depth and finned length for a given
total load.
1. Before entering Direct Selection Table No. 4 it will be
necessary to know the following:
a. Coil face velocity. Calculate using Formula 8, or
assume 500 if unable to calculate or if not
specified.
b. Total tons per sq. ft.-Calculate using Formula 10
or leaving wet bulb temperature. If interpolation
of tables required, tons per sq. ft. must be
determined.
c. Leaving water temperature. Calculate using
Formula 2 when necessary.
2. Using the entering wet bulb temperature, entering
water temperature and leaving water temperature
find the proper page of Table No. 4.
3. Enter table at proper face velocity, read down to find
the value of tons per sq. ft. or leaving wet bulb
temperature most nearly meeting the requirement. It
is suggested that 4 row coils be checked first and if
insufficient the 6 and 8 rows be checked in turn.
Usually more than one selection is possible. Select
the coil having the fewest rows and the shortest
“NTL”. Since the coil height (“W” dimension) is
subsequently determined from the face area and
finned length keep the length height ratio in mind
when selecting the finned length from Table 4. Do
not overlook the possibility of using a higher or lower
fin series to more accurately match the capacity. In
many cases the higher fin series coil will reduce the
rows deep required. See Table 2, page 7 for fin
series correction factors to apply to the values of
tons per sq. ft. in Table No. 4.
5. Calculate leaving wet bulb temperature if not directly
readable from table.
6. Calculate the leaving dry bulb temperature using
Formula 3.
7. Determine water pressure drop as shown, page 29.
8. Determine air pressure drop as shown, page 29.
To determine capacity for a given coil.
1. Before entering table it will be necessary to know:
a. Coil face velocity. Calculate using Formula 8.
b. Coil “NTL”. Determine from Table 1, page 6.
c. Rows deep and fin series. (Would be
specified.)
d. Leaving water temperature-calculate using
Formula 2.
2. Using the entering wet bulb temperature entering water
temperature and leaving water temperature, find proper
page in Table No. 4.
3. Enter table in proper coil face velocity column, “NTL”
and row depth. Read capacity in terms of tons per sq.
ft. or leaving wet bulb temperature. If the given coil
is single serpentine and tables values are given for
KWH or KWD Type Coils, follow trial and error
procedure outlined in problems 1 and 2. For other than
80 Fin Series Coils multiply the value in tons per sq. ft.
from Table No. 4 by the fin series correction factor
(Table 2, page 7).
4. Calculate leaving wet bulb if not directly readable from
table.
5. Calculate leaving dry bulb temperature using
Formula 3.
4. Using the minimum required “NTL” and the minimum
coil face area find the minimum coil height
(“W” dimension) from Table 1, page 6.
6. Calculate water pressure drop as shown, page 30.
7. Calculate air pressure drop as shown, page 29.
- 11 -
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