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Bulletin 5050 5/8” Water Cooling Coils
WATER COOLING COILS 5/8” OD TUBE
Type BW Chilled Water Coils
“The Heat Transfer Experts”
Table of Contents
PageGeneral 1
Dimensions 2
Typical Circuiting Arrangements 3
Chilled Water Cooling Coil Selection Example 4
Chilled Water Coil Worksheet Example 5
Chilled Water Coil Worksheet 6
Enthalpy of Air, table 1 7
Air Density Correction at Altitude, table 2 7
Air Density Correction at Temperature, table 3 7
Log Mean Temperature Difference, table 4 8
Basic Capacity, figure 1, 8FPI 9
Basic Capacity, figure 2, 1OFPI 10
Basic Capacity, figure e, 12 FPI 10
Capacity Correction Factor, figure 4 11
Air and Metal Thermal Resistance, figure 5 12
Water Thermal Resistance vs. Velocity, figure 6 12
Dry and Wet Surface Air Friction, figure 7 13
Water Friction Pressure Drop, figure 8 13
Header Pressure Drop, Double Circuit Coils, table 5 14
Header Pressure Drop, Full Circuit, table 6 14
Header Pressure Drop, Half Circuit, table 7 14
Header Pressure Drop, Quarter Circuit, table 8 14
Basic Formulas 15
Symbols and Subscript 16
Coil Weights 17
COIL NOMENCLATUREOrdering Data
BW L 24 48 4R 8F WR L 100Type of CoilBW - Basic Water
Tube SizeL - 5/8 Inch O.D.
Finned Height6 through 72 inches
Note: Finned height isequal to the number of:5/8" tubes high x 1.5
Finned Length12 through 240 inches
Rows Deep2 through 12
Note: Fin Depth (indirection of Airflow)# of Rows x 1.2990
Fins per Inch4 through 14
Coil CircuitingWater200 - Double150 - One and one half100 - Full075 - Three Quarters067 - Two Thirds050 - Half033 - One Third025 - QuarterSPE - Special: Can be
shown as a percent-age as above (038,167, etc.) or asFeeds/Passes.
Header LocationR - Right HandL - Left Hand
Fin PatternsFF - Flat Fin, Flat EdgeFR - Flat Fin, Ripple EdgeWF - Waffle Fin, Flat EdgeWR - Waffle Fin, Ripple
Note – A Right or Left hand Coil is determined by the location of the Outlet Connection, when facing in the same direction as the air flow.
Type BW CoilsGeneral
Colmac Type BW Water Coils are certified under ARI Standard 410-81. Capacities are based on counterflow air andwater through the coil. Application data is based on standard air conditions. Coil tested to 350 psig dry air under water.
Tubes• 5/8" O.D. seamless copper in a 1.50 inch equilateral staggered pattern.
• Mechanically or hydraulically expanded into full length fin collars.
• Copper return bends and stub connections are brazed into expanded tube ends using high temp brazing alloy.
• 4 thru 8 rows deep ARI certified (2 thru 12 rows available).
Fins• Aluminum alloy configured plate type fins (copper fin and flat plate fin available).
• 8 to 12 fins per inch ARI certified (4 thru 14 fins per inch available).
• WF and WR fin patterns ARI certified.
Headers• Seamless copper tube in accordance with ASTM B88.
• Headers individually sized to coils to minimize water pressure drop.
Coil Casing• Mill Galvanized sheet metal with full slotted flanges for convenient mounting.
• Finned heights from 6 to 72 inches.
• Finned lengths from 12 to 240 inches.
MA
NU
FAC
TURE
R
CERTIFIED TO ARI AS COMPLYIN
GW
ITH
FOR
CED
CIRC
ULATION
AIR HEATING COILS
AIR-COOLINGan d
DIMENSIONS5/8" Basic Water Coils
Fin Height Cleanable Cleanable6 to 17 in. 18 to 29 in. 30 to 43 in. 44 + in Basic Removable Plugs Removable PlugsSupply & Supply & Supply & Supply & Note 5 Water Opposite Supply End Both Ends
Rows Circuiting Return MPT Return MPT Return MPT Return MPT L D C3/C4 L2 L3 L2 L3 L2 L31 Full ** 1 1 1/4 1 1/2 2 Note 3 4 1/2 2 1/4 –– Note 1 –– –– –– ––
Partial 1 1 1/4 1 1/2 2 Note 4 4 1/2 1 1/8 2 1/2 –– –– –– –– ––2 Double ** 2 1/2 2 1/2 2 2 1/2 Note 3 6 3 –– Note 1 –– –– –– ––
Full / Partial 1 1/2 2 2 2 1/2 Note 4 6 1 1/2 2 1/2 –– 3 3/4 –– –– ––3 –– –– –– –– –– –– –– –– –– –– –– –– –– ––
Full / Partial 1 1/2 2 2 2 1/2 Note 3 7 2 1/4 –– Note 1 –– Note 2 –– Note 24 Double 2 1/2 2 1/2 2 1/2 3 Note 3 8 1/2 3 2 1/2 –– 3 3/4 –– 3 3/4 ––
Full / Partial 1 1/2 2 2 1/2 3 Note 3 8 1/2 2 1/4 2 1/2 –– 3 3/4 –– 3 3/4 ––6 Double ** 2 1/2 2 1/2 2 1/2 3 Note 3 11 3 –– Note 1 –– Note 2 –– Note 2
Full / Partial 1 1/2 2 2 1/2 3 Note 3 11 2 1/4 2 1/2 –– 3 3/4 –– 3 3/4 ––8 Double 2 1/2 2 1/2 2 1/2 3 Note 3 13 1/2 2 7/8 2 1/2 –– 3 3/4 –– 3 3/4 ––
Full / Partial 1 1/2 2 2 1/2 3 Note 3 13 1/2 2 1/4 2 1/2 –– 3 3/4 –– 3 3/4 ––10 Double ** 2 1/2 2 1/2 2 1/2 3 Note 3 16 2 7/8 –– Note 1 –– Note 2 –– Note 2
Full / Partial 1 1/2 2 2 1/2 3 Note 3 16 2 1/4 2 1/2 –– 3 3/4 –– 3 3/4 ––
**Will result in Opposite End Connections.
Notes:1. Same as appropriate "L". 5. Consult Factory for "D" when using cleanable return bends2. Add 1 3/4" to appropriate "L". 6. C1 & C2 = Flange + 1/2 Conn. Nom. OD.3. 2 1/2" plus Header Nominal OD. 7. Circuiting over "Full" requires 2 1/2 or larger headers.4. 3" plus Header Nominal OD.l 8. Intermediate tube sheets provided when finned length exceeds 54".
2
C3
D
C4
DRAIN
VENT
AIRFLOW
3 1/2 TYP
FROM CENTERLINE OF CASING5/16 HOLES ON 3” CENTERS
L2 1 1/2 TYP3/4 TYP
FIN HEIGHTMULTIPLES OF 1.50”
FINNED LENGTH, BL3
CL
CL
1 1/2 TYP
3/4 TYP
RETURN
SUPPLY
C1, TYPICAL(SEE NOTE 6)
TYPICAL CIRCUITING ARRANGEMENTS
–– FULL OR HALF IS STANDARD COIL ARRANGEMENT.–– DOUBLE CIRCUIT REDUCES WATER VELOCITY AND PRESSURE DROP IN TUBES.–– HALF AND QUARTER CIRCUIT INCREASES WATER VELOCITY AND PRESSURE DROP IN TUBES.–– DRAINABLE CIRCUIT AVAILABLE. (ALL WATER COILS SELF DRAINING BY DESIGN)–– OTHER CIRCUITING ARRANGEMENTS ARE AVAILABLE.–– RIGHT AND LEFT HAND CONNECTIONS AVAILABLE.
3
When selecting cooling coils it is advisable for economy to consider . . .
• The leaving air dry bulb temperature should be 6 or more degrees F above the entering water temperature.
• Higher air and water velocities yield higher cooling capacities. Water velocities between 4 and 8 ft/sec and airvelocities between 400 and 700 ft/min. are recommended.
EXAMPLEExample of Chilled Water Cooling Coil Selection for either Cooling and Dehumidifying or Sensible Cooling OnlyApplications.
Given or Calculated Information:
Qa Air Flow Rate, ft3/min. (std.) 2000
t1 Entering dry bulb air temperature, °F 80
t2 Leaving dry bulb air temperature, °F 58
t'1 Entering wet bulb air temperature, °F 67
t'2 Leaving wet bulb air temperature, °F 56.7
twl Entering Water temperature, °F 45
tw2 Leaving Water temperature, °F 52
Af Face Area, ft2 4
Va Air Face Velocity, ft/min. (std.) 500
SOLUTION
1. The Chilled Water Coil may be selected by using the worksheet on Page 5. The application of certain formulas may benecessary to develop input information for the worksheet selection procedure. General formulas are given on Page 14.Refer to Pages 15 and 16 for definition of symbols and subscripts.
2. When the CFM is given and the desired ft/min. in known, the required face area is known. Thus, the face dimensionsmay be assumed for the application desired.
3. Several circuits should be tried to produce a resulting water velocity between 4 and 8 ft/sec. It may be helpful to selecta water velocity of 6 ft/sec. and work backwards to find the approximate number of circuits required.
4
[ ( )] [ ]
CHILLED WATER COIL WORKSHEET JOB: EXAMPLE DATE:
I. COIL DIMENSIONS: HEIGHT: 24IN.; LENGTH: 24 IN.; TUBE SIZE: 5/8 O.D.; FINS/INCH 8
II. AIR DATA: Air Quantity, Qa = 2000 SCFM
Air Velocity, Va = Qa = 2000 SCFM = 500 ft/min. (std)Af 4ft2
ta = t1–t2 = 80 - 58 = 22°F.
t’1 = 67.0; t’2 = 56.7
h = h1 - h2 = 31.62 - 24.29 = 7.33 Btu/lb., (Table 1)
Sensible and Total Heat Loads,qs = 1.08 SCFM TA = 1.08 (2000) ( 22 ) = 47,520 Btuh
qt = 4.5 SCFM h = 4.5 (2000) (7.33) = 65,970 BtuhqsAir Sensible Heat Ratio, r = = .724qt
III. WATER DATA: tW = tw2 - twl = 52 - 45 = 7°F.qt 65,970GPM required = = = 18.85 GPM
500 tw 500 (7)
Vw = 1.194 GPM = 1.194 (18.85) = 5.6 ft/secNc 4
(Quarter Circuit)
IV. THERMAL CHARACTERISTICS.Log Mean Temp. Difference (Table 4)
TL = t1 – tw2 = 80–52 = 28°F.
TS = t2 – twl = 58–45 = 13°F.
Tm = 19.63°F
V. Unit Capacity (Figs. 1-6 and 4a)
K R (198) (1.18) (.0919)KT = = = 215 Btu/hr ft2°F row
(Ra + Rm) + Rw (.085) + (.015)
Number of Rows, Nr
Nr =qt = 65,970 = 3.9 or 4 rows
At tm KT (4) (19.63) (215)
v. DRY OR WET SURFACE AIR FRICTION: Fig.7
Pst’Dry = Nr ( Pst/Nr) = 4 ( .079 ) = .32 in. H2O
Psw, Wet = Nr ( Psw/Nr) = 4 ( .13 ) = .52 in. H2O
VI. WATER FRICTION: Table 8, 9, Fig. 8
Pw = Ph + Le PtLeFt
Ft = .77 + ( 54.5 ) ( .245) 1.03 = .14.5 ft. H2O
5
[ ( )] [ ]
CHILLED WATER COIL WORKSHEET JOB: DATE:
I. COIL DIMENSIONS: HEIGHT: IN.; LENGTH: IN.; TUBE SIZE: O.D.; FINS/INCH .
II. AIR DATA: Air Quantity, Qa = SCFM
Air Velocity, Va = Qa = SCFM = ft/min. (std)Af ft2
ta = t1–t2 = - = °F.
t’1 = ; t’2 = .
h = h1 - h2 = - = Btu/lb., (Table 1)
Sensible and Total Heat Loads,qs = 1.08 SCFM TA = 1.08 ( ) ( ) = Btuh
qt = 4.5 SCFM h = 4.5 ( ) ( ) = BtuhqsAir Sensible Heat Ratio, r = = .qt
III. WATER DATA: tW = tw2 - twl = – = °F.qtGPM required = = = GPM
500 tw 500 ( )
Vw = 1.194 GPM = 1.194 ( ) = ft/secNc ( )
IV. THERMAL CHARACTERISTICS.Log Mean Temp. Difference (Table 4)
TL = t1 – tw2 = – = °F.
TS = t2 – twl = – = °F.
Tm = °F
V. Unit Capacity (Figs. 1-6 and 4a)
K R ( ) ( ) ( )KT = = = Btu/hr ft2°F row
(Ra + Rm) + Rw ( ) + ( )
Number of Rows, Nr
Nr =qt = = rows
At tm KT ( ) ( ) ( )
v. DRY OR WET SURFACE AIR FRICTION: Fig.7
Pst’Dry = Nr ( Pst/Nr) = ( ) = in. H2O
Psw, Wet = Nr ( Psw/Nr) = ( ) = in. H2O
VI. WATER FRICTION: Table 5, 6, 7, 8, 9, Fig. 8
Pw = Ph + Le PtLeFt
Ft = _____ + ( )( ) = ft. H2O
6
ENTHALPY OF MOIST AIR
Enthalpy of moist air in BTU per pound of dry air.
°F TENTHS OF DEGREESWB .0 .1 .2 .3 .4 .5 .6 .7 .8 .940 15.23 15.28 15.32 15.37 15.42 15.46 15.51 15.56 15.60 15.6541 15.70 15.74 15.79 15.84 15.89 15.93 15.98 16.03 16.08 16.1242 16.17 16.22 16.27 16.32 16.37 16.41 16.46 16.51 16.56 16.6143 16.66 16.71 16.76 16.80 16.85 16.90 16.95 17.00 17.05 17.1044 17.15 17.20 17.25 17.30 17.35 17.40 17.45 17.50 17.55 17.6045 17.65 17.70 17.75 17.80 17.85 17.91 17.96 18.01 18.06 18.1146 18.16 18.21 18.26 18.32 18.37 18.42 18.47 18.52 18.58 18.6347 18.68 18.73 18.79 18.84 18.89 18.95 19.00 19.05 19.10 19.1648 19.21 19.27 19.32 19.37 19.43 19.48 19.54 19.59 19.64 19.7049 19.75 19.81 19.86 19.92 19.97 20.03 20.08 20.14 20.19 20.2550 20.30 20.36 20.41 20.47 20.53 20.58 20.64 20.69 20.75 20.8151 20.86 20.92 20.98 21.03 21.09 21.15 21.21 21.26 21.32 21.3852 21.44 21.49 21.55 21.61 21.67 21.73 21.79 21.84 21.90 21.9653 22.02 22.08 22.14 22.20 22.26 22.32 22.38 22.44 22.50 22.5654 22.62 22.68 22.74 22.80 22.86 22.92 22.98 23.04 23.10 23.1655 23.22 23.28 23.34 23.41 23.47 23.53 23.59 23.65 23.72 23.7856 23.84 23.90 23.97 24.03 24.10 24.16 24.22 24.29 24.35 24.4257 24.48 24.54 24.61 24.67 24.74 24.80 24.86 24.93 24.99 25.0658 25.12 25.19 25.25 25.32 25.38 25.45 25.52 25.58 25.65 25.7159 25.78 25.85 25.92 25.98 26.05 26.12 26.19 26.26 26.32 26.3960 26.46 26.53 26.60 26.67 26.74 26.81 26.87 26.94 27.01 27.0861 27.15 27.22 27.29 27.36 27.43 27.50 27.57 27.64 27.71 27.7862 27.85 27.92 27.99 28.07 28.14 28.21 28.28 28.35 28.43 28.5063 28.57 28.64 28.72 28.79 28.87 28.94 29.01 29.09 29.16 29.2464 29.31 29.39 29.46 29.54 29.61 29.69 29.76 29.84 29.91 29.9965 30.06 30.14 30.21 30.29 30.37 30.45 30.52 30.60 30.68 30.7566 30.83 30.91 30.99 31.07 31.15 31.23 31.30 31.38 31.46 31.5467 31.62 31.70 31.78 31.86 31.94 32.02 32.10 32.18 32.26 32.3468 32.42 32.50 32.59 32.67 32.75 32.84 32.92 33.00 33.08 33.1769 33.25 33.33 33.42 33.50 33.59 33.67 33.75 33.84 33.92 34.0170 34.09 34.18 34.26 34.35 34.43 34.52 34.61 34.69 34.78 34.8671 34.95 35.04 35.13 35.21 35.30 35.39 35.48 35.57 35.65 35.7472 35.83 35.92 36.01 36.10 36.19 36.29 36.38 36.47 36.56 36.6573 36.74 36.83 36.92 37.02 37.11 37.20 37.29 37.38 37.48 37.5774 37.66 37.76 37.85 37.95 38.04 38.14 38.23 38.33 38.42 38.5275 38.61 38.71 38.80 38.90 38.99 39.09 39.19 39.28 39.38 39.4776 39.57 39.67 39.77 39.87 39.97 40.07 40.17 40.27 40.37 40.4777 40.57 40.67 40.77 40.87 40.97 41.08 41.18 41.28 41.38 41.4878 41.58 41.68 41.79 41.89 42.00 42.10 42.20 42.31 42.41 42.5279 42.62 42.73 42.83 42.94 43.05 43.16 43.26 43.37 43.48 43.5880 43.69 43.80 43.91 44.02 44.13 44.24 44.34 44.45 44.56 44.67
Table 1
Air density ratios with standard air as unity are tabulated for various altitudes in Table 2 and for various tempera-tures in Table 3. If a correction is made for both altitude and temperature, multiply ratios together.
Table 2
ALTITUDE FEETALT. DENS. ALT. DENS.
0 1.000 5000 0.826500 0.981 5500 0.811
1000 0.962 6000 0.7961500 0.944 6500 0.7812000 0.926 7000 0.7662500 0.908 7500 0.7513000 0.891 8000 0.7363500 0.875 8500 0.7224000 0.858 9000 0.7084500 0.842 9500 0.6945000 0.826 10,000 0.680
TEMPERATURE FAHRENHEITTEMP. DENS. TEMP. DENS. TEMP. DENS. TEMP. DENS.
0 1.152 100 0.946 200 0.803 300 0.69810 1.128 110 0.930 210 0.791 310 0.68920 1.104 120 0.914 220 0.779 320 0.68030 1.082 130 0.898 230 0.768 330 0.67140 1.060 140 0.883 240 0.757 340 0.66250 1.039 150 0.869 250 0.746 350 0.65460 1.019 160 0.855 260 0.736 360 0.64670 1.000 170 0.841 270 0.726 370 0.63880 0.982 180 0.828 280 0.716 380 0.63190 0.964 190 0.815 290 0.707 390 0.624
100 0.946 200 0.803 300 0.698 400 0.617
Table 3
Standard Air is defined as weighing 0.075 pounds per cubic foot at sea level (29.92" Hg Barometric Pressure)and at 70° Fahrenheit.
7
LEA
ST o
r GR
EATE
ST T
ERM
INA
L TE
MPE
RA
TUR
E D
IFFE
REN
CE
12
34
56
78
910
1214
1618
2022
2426
2830
3234
3638
4042
441
1.00
1.40
1.51
2.05
2.45
2.75
3.00
3.25
3.51
3.80
4.40
4.90
5.40
5.80
6.20
6.70
7.10
7.50
8.00
8.40
8.75
9.20
9.60
10.0
010
.40
10.8
011
.25
21.
402.
002.
452.
803.
253.
604.
004.
354.
705.
005.
606.
206.
757.
257.
808.
308.
809.
259.
8010
.30
10.8
011
.30
11.8
012
.30
12.7
513
.20
13.7
03
1.51
2.45
3.00
3.45
3.80
4.25
4.70
5.10
5.50
5.80
6.50
7.20
7.80
8.45
9.00
9.50
10.0
010
.55
11.1
011
.60
12.2
012
.70
13.2
513
.75
14.3
014
.80
15.4
04
2.05
2.80
3.45
4.00
4.45
4.90
5.35
5.80
6.20
6.60
7.30
8.00
8.65
9.25
9.80
10.5
011
.00
11.6
012
.20
12.7
513
.30
13.8
514
.50
15.0
015
.60
16.2
016
.70
52.
453.
253.
804.
455.
005.
455.
956.
406.
757.
208.
008.
759.
5010
.20
10.8
011
.45
12.0
012
.65
13.2
513
.90
14.5
015
.00
15.6
016
.20
16.7
517
.40
17.9
06
2.75
3.60
4.25
4.90
5.45
6.00
6.50
7.00
7.50
7.90
8.75
9.50
10.2
011
.00
11.6
012
.25
12.9
513
.60
14.2
014
.90
15.5
016
.10
16.6
517
.25
17.8
018
.50
19.0
57
3.00
4.00
4.70
5.35
5.95
6.50
7.00
7.50
8.00
8.45
9.30
10.2
010
.90
11.7
012
.45
13.2
013
.75
14.5
015
.20
15.8
016
.45
17.0
017
.70
18.4
019
.00
19.5
020
.20
83.
254.
355.
105.
806.
407.
007.
508.
008.
509.
0010
.00
10.8
011
.65
12.5
013
.20
13.9
014
.55
15.2
516
.00
16.6
517
.25
17.9
518
.55
19.2
219
.80
20.5
021
.20
93.
514.
705.
506.
206.
757.
508.
008.
509.
009.
5010
.50
11.4
512
.25
13.0
013
.80
14.2
015
.25
16.0
016
.75
17.5
018
.20
18.8
019
.50
20.2
020
.85
21.5
022
.10
103.
805.
005.
806.
607.
207.
908.
459.
009.
5010
.00
11.0
012
.00
12.9
013
.70
14.5
015
.25
16.0
016
.75
17.5
018
.20
18.8
019
.50
20.2
521
.00
21.6
022
.25
22.8
512
4.40
5.60
6.50
7.30
8.00
8.75
9.30
10.0
010
.50
11.0
012
.00
13.0
014
.00
14.8
515
.70
16.6
017
.45
18.2
018
.95
19.7
020
.45
21.2
021
.85
22.6
023
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24.0
024
.75
144.
906.
207.
208.
008.
759.
5010
.20
10.8
011
.45
12.0
013
.00
14.0
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.00
16.0
016
.90
17.8
018
.70
19.5
020
.30
21.2
021
.85
22.7
023
.45
24.1
524
.90
25.6
026
.30
165.
406.
757.
808.
659.
5010
.20
10.9
011
.65
12.2
512
.90
14.0
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.00
16.0
017
.00
18.0
019
.00
19.8
020
.70
21.5
022
.40
23.1
023
.90
24.7
025
.50
26.4
027
.00
27.7
518
5.80
7.25
8.45
9.25
10.2
011
.00
11.7
012
.50
13.0
013
.70
14.8
516
.00
17.0
018
.00
19.0
020
.10
21.0
022
.00
22.8
023
.70
24.5
025
.20
26.0
026
.70
27.6
528
.40
29.1
020
6.20
7.80
9.00
9.80
10.8
011
.60
12.4
513
.20
13.8
014
.50
15.7
016
.80
18.0
019
.00
20.0
021
.10
22.1
023
.00
24.0
024
.80
25.7
026
.50
27.3
028
.10
29.0
029
.75
30.6
022
6.70
8.30
9.50
10.5
011
.45
12.2
513
.20
13.9
014
.20
15.2
516
.60
17.8
019
.00
20.1
021
.10
22.0
023
.10
24.0
024
.90
25.8
526
.75
27.6
028
.50
29.4
030
.20
31.1
031
.85
247.
108.
8010
.00
11.0
012
.00
12.9
513
.75
14.5
515
.25
16.0
017
.45
18.7
019
.80
21.0
022
.10
23.1
024
.00
25.0
026
.00
27.0
027
.90
28.8
029
.70
30.5
031
.40
32.3
033
.20
267.
509.
2510
.55
11.6
012
.65
13.6
014
.50
15.2
516
.00
16.7
518
.20
19.5
020
.70
22.0
023
.00
24.0
025
.00
26.0
027
.00
28.0
029
.00
29.9
030
.75
31.6
032
.50
33.4
534
.30
288.
009.
8011
.10
12.2
013
.25
14.2
015
.20
16.0
016
.75
17.5
018
.95
20.3
021
.50
22.8
024
.00
24.9
026
.00
27.0
028
.00
29.0
030
.00
30.9
531
.90
32.8
033
.70
34.5
535
.45
308.
4010
.30
11.6
012
.75
13.9
014
.90
15.8
016
.65
17.5
018
.20
19.7
021
.20
22.4
023
.70
24.8
025
.85
27.0
028
.00
29.0
030
.00
31.0
032
.00
33.0
034
.00
34.8
535
.75
36.6
532
8.75
10.8
012
.20
13.3
014
.50
15.5
016
.45
17.2
518
.20
18.8
020
.45
21.8
523
.10
24.5
025
.70
26.7
527
.90
29.0
030
.00
31.0
032
.00
33.0
034
.00
35.0
536
.00
36.9
037
.80
349.
2011
.30
12.7
013
.85
15.0
016
.10
17.0
017
.95
18.8
019
.50
21.2
022
.70
23.9
025
.20
26.5
027
.60
28.8
029
.90
30.9
532
.00
33.0
034
.00
35.0
036
.10
37.1
038
.00
38.9
036
9.60
11.8
013
.25
14.5
015
.60
16.6
517
.70
18.5
519
.50
20.2
521
.85
23.4
524
.70
26.0
027
.30
28.5
029
.70
30.7
531
.90
33.0
034
.00
35.0
036
.00
37.0
038
.05
39.1
040
.00
3810
.00
12.3
013
.75
15.0
016
.20
17.2
518
.40
19.2
220
.20
21.0
022
.60
24.1
525
.50
26.7
028
.10
29.4
030
.50
31.6
032
.80
34.0
035
.05
36.1
037
.00
38.0
039
.00
40.1
041
.10
4010
.40
12.7
514
.30
15.6
016
.75
17.8
019
.00
19.8
020
.85
21.6
023
.45
24.9
026
.40
27.6
529
.00
30.2
031
.40
32.5
033
.70
34.8
536
.00
37.1
038
.05
39.0
040
.00
41.0
042
.00
4210
.80
13.2
014
.80
16.2
017
.40
18.5
019
.50
20.5
021
.50
22.2
524
.00
25.6
027
.00
28.4
029
.75
31.1
032
.30
33.4
534
.55
35.7
536
.90
38.0
039
.10
40.1
041
.00
42.0
043
.00
4411
.25
13.7
015
.40
16.7
017
.90
19.0
520
.20
21.2
022
.10
22.8
524
.75
26.3
027
.75
29.1
030
.60
31.8
533
.20
34.3
035
.45
36.6
537
.80
38.9
040
.00
41.1
042
.00
43.0
044
.00
4611
.70
14.1
015
.90
17.2
018
.50
19.0
720
.70
21.7
222
.75
23.5
525
.50
27.0
028
.50
29.9
031
.40
32.7
534
.05
35.2
036
.30
37.5
038
.70
39.8
040
.90
42.0
043
.00
44.0
044
.90
4812
.00
14.6
016
.45
17.8
019
.00
20.2
021
.30
22.4
023
.40
24.2
026
.20
27.7
529
.25
30.7
032
.20
33.6
034
.95
36.0
037
.15
38.4
039
.60
40.7
541
.85
43.0
043
.95
44.8
546
.08
5012
.50
15.0
016
.80
18.2
519
.50
20.8
021
.80
23.0
024
.00
24.8
026
.85
28.5
030
.00
31.6
033
.00
34.4
035
.75
36.9
038
.00
39.3
040
.50
41.6
042
.75
43.9
044
.80
46.0
047
.00
5212
.90
15.4
017
.30
18.8
020
.00
21.3
522
.45
23.5
024
.55
25.5
027
.50
29.1
530
.70
32.2
033
.70
35.1
536
.55
37.7
038
.80
40.1
541
.40
42.5
043
.70
44.7
045
.50
47.0
648
.10
5413
.30
15.7
517
.80
19.3
020
.60
21.8
023
.00
24.1
025
.10
26.1
028
.10
29.7
531
.40
32.8
034
.45
35.9
037
.35
38.5
039
.60
41.0
042
.30
43.4
044
.60
45.6
346
.71
47.7
949
.14
5613
.70
16.2
018
.30
19.8
021
.20
22.4
523
.50
24.7
025
.70
26.7
028
.70
30.4
532
.00
33.6
035
.20
36.7
038
.15
39.3
540
.40
41.8
043
.20
44.3
045
.36
46.3
647
.60
48.7
249
.84
5814
.00
16.5
018
.70
20.4
021
.70
22.8
524
.10
25.2
026
.20
27.2
529
.30
31.1
032
.70
34.4
036
.80
37.3
538
.90
40.2
041
.25
42.7
044
.10
45.2
446
.51
47.2
748
.43
49.7
050
.75
6014
.40
16.9
019
.20
20.9
022
.20
23.4
524
.65
25.7
526
.75
27.8
029
.90
31.7
233
.40
35.0
036
.50
38.1
039
.70
41.0
042
.00
43.5
045
.00
46.0
247
.10
48.3
649
.50
50.4
051
.72
6214
.70
17.3
019
.70
21.4
022
.70
23.8
525
.20
26.3
527
.35
28.5
030
.50
32.4
034
.00
35.7
037
.25
38.8
540
.45
41.7
042
.85
44.4
545
.57
46.8
147
.86
49.2
950
.40
51.3
352
.39
6415
.10
17.7
020
.20
21.9
023
.10
24.4
525
.70
26.9
027
.85
29.0
031
.10
33.0
034
.70
36.5
038
.00
39.5
541
.20
42.4
043
.70
45.1
246
.30
47.5
548
.96
50.1
151
.20
51.8
453
.44
6615
.40
18.1
020
.60
22.4
023
.55
24.8
526
.25
27.5
028
.45
29.7
031
.70
33.7
035
.25
37.2
038
.70
40.2
542
.00
43.1
544
.50
45.8
747
.19
48.3
149
.69
50.8
252
.14
53.1
354
.45
6815
.75
18.5
021
.10
22.8
024
.00
25.4
526
.75
28.0
029
.00
30.2
532
.25
34.3
036
.00
37.9
039
.40
41.0
042
.70
43.8
045
.22
46.7
148
.14
49.0
950
.52
51.6
853
.04
54.0
655
.21
7016
.10
18.9
021
.50
23.4
024
.50
25.8
527
.30
28.5
029
.50
30.8
532
.80
35.0
036
.60
38.5
040
.20
41.7
543
.50
44.5
046
.06
47.4
648
.65
50.0
551
.38
52.5
053
.90
54.8
156
.14
7216
.45
19.2
522
.00
23.8
025
.00
26.4
527
.80
29.0
030
.10
31.4
533
.50
35.6
037
.25
39.2
040
.75
42.5
044
.15
44.9
046
.80
48.2
449
.60
51.1
252
.20
53.2
854
.72
55.8
056
.88
7416
.75
19.6
022
.40
24.2
525
.45
26.8
528
.40
29.6
030
.70
32.0
034
.00
36.2
037
.90
39.8
041
.50
43.1
544
.85
45.8
847
.46
48.8
450
.32
51.8
052
.91
54.3
955
.35
56.3
657
.72
7617
.10
20.0
022
.80
24.7
525
.80
27.4
029
.00
30.1
531
.20
32.5
034
.60
36.8
038
.50
40.5
042
.20
43.8
545
.60
46.3
648
.03
49.5
551
.30
52.4
453
.96
55.1
056
.24
57.3
858
.90
7817
.40
20.4
523
.20
25.2
026
.40
27.8
029
.50
30.7
031
.75
33.1
035
.20
37.4
039
.10
41.2
042
.80
44.5
546
.02
47.1
948
.90
50.3
151
.63
53.0
454
.60
55.7
757
.33
58.3
459
.67
8017
.70
20.8
023
.70
25.7
026
.75
28.4
030
.00
31.1
532
.40
33.7
035
.70
38.0
039
.70
41.7
543
.50
44.8
046
.40
48.0
049
.60
51.2
052
.56
54.0
055
.44
56.8
058
.00
59.2
060
.40
Table 4Log Mean Temperature Differences
LEAST or GREATEST TERMINAL TEMPERATURE DIFFERENCE
8
Figure 1
Basic Capacity - 8 FPI(WF or WR Fins)
r = qs/qt
Air Sensible Heat Ratio
Bas
ic C
apac
ity K
,B
tu /
hr. °
F ft2 r
ow
SFPMVa = 700
Va = 600
Va = 500
Va = 400
240
220
200
180
160
0.5 0.6 0.7 0.8 0.9 1.0
9
Basic Capacity - 10 FPI(WF or WR Fins)
qs/qtAir Sensible Heat Ratio
Figure 2
Basic Capacity - 12 FPI(WF or WR Fins)
Bas
ic C
apac
ity K
,B
tu /
hr. °
F ft2 r
ow
SFPMVa = 700
Va = 600
Va = 500
Va = 400
260
240
220
200
Figure 3
Bas
ic C
apac
ity K
,B
tu /
hr. °
F ft2 r
ow
SFPMVa = 700
Va = 600
Va = 500
Va = 400
260
240
220
200
180
0.5 0.6 0.7 0.8 0.9 1.0
10
Basic Capacity Corrections Factor(WF or WR Fins)
Figure 4
Va (ft/min)
1.35
1.30
1.25
1.20
1.15
1.10300 400 500 600 700 800
Figure 4a R , Characteristic thermal resistance values(WF or WR Fins)
FPI R8 0.0919
10 0.097612 0.1032
12 FPI
10 FPI
8 FPI
11
µ
Figure 5
Figure 6
0.12
0.10
0.09
0.08
0.07
0.06
Ra
+ R
m (h
r °F
ft2 /Btu
)
300 400 500 600 700 800
Air And Metal Thermal Resistance(WF or WR Fins)
Va (ft/min)Water Thermal Resistance
(WF or WR Fins)0.07
0.06
0.05
0.04
0.03
0.02
0.01
Rw
(hr °
F ft2 /B
tu)
1.5 2 3 4 5 6 7 8
Vw (ft/sec)12
12 FPI
10 FPI
8 FPI
Figure 7
Dry and Wet Surface Air FrictionType WF or WR Fins
12 FPI10 FPI8 FPI
} Pst / Nr
12 FPI10 FPI
8 FPI} Psw / Nr
Dry FinsSFPM 8 FPI 10 FPI 12 FPI300 0.034 0.041 0.048400 0.054 0.065 0.075500 0.079 0.092 0.105600 0.107 0.122 0.139700 0.138 0.155 0.175800 0.173 0.191 0.215
Wet FinsSFPM 8 FPI 10 FPI 12 FPI300 0.053 0.068 0.086400 0.088 0.107 0.130500 0.130 0.152 0.179600 0.180 0.203 0.232700 0.237 0.259 0.289800 0.300 0.320 0.350
1,000
0.100
0.010300 400 500 600 700 800
Air Velocity (SFPM)
P (in
H20
per
Row
)
Figure 8
Water Friction Pressure Drop
Pt/L
eF t (ft
H2O
/ft)
0.50
0.40
0.30
0.20
0.100.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.0151.5 2 3 4 5 6 7 8
Vw (ft/sec)
13
Header Pressure Drop Ph, ft H2O
Table 5Double Circuit
No. Tubes Water Velocity, FPSIn Face 1 2 3 4 6 8
8 .22 .83 1.85 3.22 7.20 12.7510 .33 1.30 2.85 5.00 10.20 19.9812 .16 .57 1.21 2.11 4.5 7.7514 .22 .77 1.65 2.80 6.05 10.5016 .27 .98 2.11 3.60 7.75 13.4518 .33 1.21 2.64 4.50 9.80 17.0020 .15 .55 1.18 2.00 4.15 7.0022 .18 .64 1.39 2.35 4.90 8.4024 .23 .76 1.61 2.74 5.80 9.9926 .25 .88 1.88 3.20 6.75 11.4028 .29 1.01 2.15 3.60 7.70 13.1030 .14 .50 1.05 1.80 3.79 6.4032 .16 .56 1.19 2.00 4.20 7.1034 .18 .62 1.30 2.25 4.70 7.9936 .20 .70 1.46 2.50 5.20 8.98
Table 6Full Circuit
No. Tubes Water Velocity, FPSIn Face 1 2 3 4 6 8
8 .07 .27 .61 1.07 2.40 4.2210 .11 .42 .94 1.66 3.70 6.5012 .05 .19 .41 .72 1.59 2.7414 .07 .25 .56 .99 2.12 3.7016 .09 .33 .72 1.24 2.74 4.7818 .11 .41 .91 1.59 3.42 6.0020 .05 .20 .44 .75 1.64 2.8222 .07 .25 .53 .91 1.97 3.3524 .08 .29 .62 1.08 2.30 4.0026 .09 .34 .73 1.24 2.70 4.6428 .10 .39 .84 1.44 3.09 5.2830 .05 .19 .41 .70 1.50 2.6032 .06 .21 .46 .78 1.70 2.9234 .06 .24 .51 .87 1.89 3.3036 .07 .27 .57 .99 2.25 3.65
Table 7Half Circuit
No. Tubes Water Velocity, FPSIn Face 1 2 3 4 6 8
8 .03 .12 .27 .48 1.08 1.7510 .05 .15 .42 .75 1.65 2.8912 .02 .09 .19 .33 .72 1.2614 .03 .12 .25 .44 .98 1.7516 .04 .15 .33 .57 1.26 2.1718 .05 .19 .41 .72 1.59 2.7520 .03 .11 .24 .42 .92 1.6222 .03 .13 .29 .51 1.11 1.9524 .04 .15 .34 .60 1.31 2.3026 .05 .18 .41 .69 1.54 2.7128 .05 .21 .46 .82 1.79 3.1230 .03 .11 .23 .40 .88 1.5232 .03 .12 .26 .45 1.00 1.7534 .04 .14 .30 .52 1.10 1.9536 .04 .15 .33 .57 1.25 2.20
Table 8Quarter Circuit
No. Tubes Water Velocity, FPSIn Face 1 2 3 4 6 8
8 .02 .08 .19 .34 .75 1.3112 .01 .05 .12 .22 .48 .8616 .02 .10 .22 .39 .86 1.5220 .02 .08 .18 .32 .72 1.2724 .03 .12 .26 .46 1.01 1.8028 .04 .16 .35 .63 1.40 2.5032 .02 .09 .20 .35 .78 1.3636 .03 .11 .25 .44 .99 1.73
Table 9Water Friction Temperature Correction Factor, Ft
Ave. WaterTemp., °F 40 50 60 70 80 90 100Correction
Factor 1.06 1.03 1.00 .97 .94 .91 .88
14
1. Air Face Velocity, std. ft/min.
Va = SCFM/Af
2. Sensible Cooling Load, Btuh
qs = 1.10 CFM ta
= 1.10 CFM (t1 - t2)
3. Leaving Dry Bulb Air Temperature, °F qst2 = t1 – ––––––––––– 1.10 CFM
4. Total Cooling Load, Btuh
a. qt = 4.5 CFM h
= 4.5 CFM (h1 - h2)
b. qt = 500 GPM TW
= 500 GPM (twl - tw2)
5. Air Sensible Heat Ratio
a. r = qs/qt
b. (t1 - t2) .244 r = ––––––––––
h
6. Water Flow Rate, GPM qt
GPM = ––––––––––– 500 tw
7. Water Velocity, ft/sec.1.194 GPM
Vw = ––––––––––– No. of circuits
FORMULAS
8. Log Mean Temperature Difference, °F(t1 - tw2) – (t2 - twl)
tm = –––––––––––––––––––t1 - tw2
In –––––––––––[ t2 - twl ]9. Total Equivalent Length of Coil
Circuit, ft.
Le = 0.0833 LsNt + Kb Nt - 1[( Nc) ( Nc
)]
10. Unit Capacity, Btu/hr ft2, °F row
K RKT = ––––––––––––––––
(Ra + Rm) + Rw
11. Number of Rows, Nrqt
Nr = –––––––– Af tmKt
12. Dry or Wet Surface Air Friction, in H2O
Pst, Dry = Nr ( Pst/Nr)
Psw, Wet = Nr ( Psw/Nr)
13. Water Friction, ft. H2O
Pw = Ph +Le Pt Ft [ ( LeFt) ]
15
Af Face Area, ft2
qt Total heat capacity, Btuh
qs Sensible heat capacity, Btuh
r Air sensible heat ratio
tm Log mean temperature difference, °F
tw Water temperature difference, °F
ta Air temperature difference, °F
twl Inlet water temperature, °F
tw2 Outlet water temperature, °F
t1 Entering dry bulb air temperature, °F
t2 Leaving dry bulb air temperature, °F
t'1 Entering wet bulb air temperature, °F
t'2 Leaving wet bulb air temperature, °F
h1 Entering air enthalpy, Btu/lb. dry air
h2 Leaving air enthalpy, Btu/lb. dry air
h Enthalpy difference, Btu/lb. dry air
Pst Air pressure drop, dry surface, in H2O/row
Psw Air pressure drop, wet surface, in H2O/row
Ph Water pressure drop from headers, ft. H2O
Pt Water Pressure drop from tubes, ft. H2O
Pw Total water pressure drop, ft. H2O
Va Air face velocity, ft/min.
Vw Water velocity, ft/sec.
Le Equivalent tube length, ft.
Ls Length of straight coil tube in one pass, inches
Nt Number of tubes in coil
Nc Number of tube circuits in coil
Nr Number of tube rows
Kb Length of coil circuit per bend, 18 inches
Ft Temperature correction factor
Qa Air flow rate, ft3/min.
K Basic capacity, Btu/hr ft2 °F
KT Unit capacity, Btu/hr ft2 °F
Capacity correction factor
R Characteristic thermal resistance, hr °F ft2/Btu
Ra Air film thermal resistance, hr °F ft2/Btu
Rm Metal thermal resistance, hr °F ft2/Btu
Rw Water film thermal resistance, hr °F ft2/Btu
SYMBOLS AND SUBSCRIPTS
16
COIL WEIGHTS – DRY – POUNDSFINNED LENGTH INCHES
FinRows Height 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120
12 17 20 23 27 30 34 37 41 44 47 51 54 58 61 64 68 71 75 7815 19 23 27 31 34 38 42 46 50 53 57 61 65 69 72 76 80 84 8818 22 26 30 34 38 43 47 51 55 59 64 68 72 76 80 84 89 93 9721 27 32 36 41 45 50 54 59 64 68 73 77 82 86 91 96 100 105 1091 24 30 35 40 45 50 55 59 64 69 74 79 84 89 94 99 104 109 114 11927 33 38 43 49 54 59 65 70 76 81 86 92 97 102 108 113 118 124 12930 42 48 54 60 65 71 77 83 88 94 100 106 111 117 123 129 134 140 14633 46 52 58 64 70 76 83 89 95 101 107 113 119 126 132 138 144 150 15636 49 56 62 69 75 82 88 95 102 108 115 121 128 134 141 147 154 160 16712 20 25 30 35 40 45 50 55 60 64 69 74 79 84 89 94 99 104 10915 23 29 35 40 46 52 58 63 69 75 81 86 92 98 104 109 115 121 12718 26 33 39 46 52 59 66 72 79 85 92 98 105 111 118 124 131 137 14421 32 40 47 54 62 69 76 84 91 98 106 113 120 127 135 142 149 157 1642 24 36 44 52 60 68 76 84 93 101 109 117 125 133 141 149 157 165 173 18127 40 49 57 66 75 84 93 102 111 120 128 137 146 155 164 173 182 190 19930 50 60 69 79 89 98 108 118 127 137 147 156 166 176 185 195 205 214 22433 54 65 75 86 96 107 117 127 138 148 159 169 180 190 200 211 221 232 24236 59 70 81 92 103 115 126 137 148 160 171 182 193 204 216 227 238 249 26012 28 37 45 54 62 71 79 88 96 105 113 122 130 139 147 155 164 172 18115 33 43 53 63 73 83 93 103 114 124 134 144 154 164 174 184 194 204 21418 38 50 61 73 85 96 108 119 131 143 154 166 178 189 201 212 224 236 24721 46 59 72 86 99 112 125 138 151 165 178 191 204 217 230 244 257 270 2834 24 51 66 81 95 110 125 140 154 169 184 199 213 228 243 258 272 287 302 31627 57 73 89 106 122 138 155 171 187 203 220 236 252 269 285 301 318 334 35030 69 87 105 123 140 158 176 194 212 230 248 265 283 301 319 337 355 373 39033 75 94 114 133 153 172 191 211 230 250 269 289 308 327 347 366 386 405 42436 81 102 123 144 165 186 207 228 249 270 291 312 333 354 375 396 417 438 45912 36 48 60 72 84 96 108 121 133 145 157 169 181 193 205 217 229 241 25315 43 58 72 86 101 115 129 144 158 172 187 201 216 230 244 259 273 287 30218 50 67 83 100 117 133 150 167 184 200 217 234 250 267 284 301 317 334 35121 60 79 98 117 136 155 174 193 212 231 250 269 288 307 326 345 364 383 4026 24 67 88 109 131 152 174 195 216 238 259 280 302 323 345 366 387 409 430 45127 74 98 121 145 169 193 216 240 264 287 311 335 359 382 406 430 453 477 50130 88 114 140 166 192 218 244 270 296 322 349 375 401 427 453 479 505 531 55733 96 124 152 181 209 238 266 294 323 351 380 408 436 465 493 522 550 578 60736 103 134 165 196 226 257 288 319 349 380 411 442 472 503 534 565 595 626 65712 45 60 76 91 107 122 138 153 169 185 200 216 231 247 262 278 293 309 32515 53 72 91 109 128 147 165 184 203 221 240 259 277 296 315 333 352 371 38918 62 84 105 127 149 171 193 214 236 258 280 301 323 345 367 389 410 432 45421 73 98 123 148 173 198 223 248 272 297 322 347 372 397 422 447 472 497 5228 24 82 110 138 166 194 222 250 278 306 334 362 390 418 446 474 502 530 558 58627 91 122 153 184 216 247 278 309 340 371 403 434 465 496 527 558 589 621 65230 107 141 175 210 244 278 312 347 381 415 449 484 518 552 587 621 655 689 72433 116 154 191 228 266 303 341 378 415 453 490 528 565 602 640 677 715 752 78936 126 166 207 247 288 328 369 409 450 490 531 571 612 652 693 734 774 815 855
NOTES:1. FOR WATER COIL OPERATING WEIGHTS, ADD DRY COIL WEIGHTS TO 1.32 X FACE AREA X ROWS
[(W OP = W DRY + (1.32 X FDA X 12)]2. WEIGHTS BASED ON 10 FPI COILS; VARIANCE FOR 6, 8, AND 12 FPI IS LESS THAN 5% OF LISTED WEIGHT.
17
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