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REFRIGERANT PIPING DESIGN
Selecting Field-Supplied Copper Tubing
Table 31: Linear Thermal Expansion of Copper Tubing in Inches.
Pipe
Length
35°
40°
45°
1
10
0.04
0.04
0.05
20
0.08
0.08
0.10
30
0.12
0.12
0.15
40
0.16
0.16
0.20
50
0.20
0.20
0.25
60
0.24
0.24
0.30
Pipe length baseline temperature = 0°F. "Expansion of Carbon, Copper and Stainless Steel Pipe," The Engineers' Toolbox, www.engineeringtoolbox.com.
1
Figure 15: Coiled Expansion Loops and Offsets.
L
R
Large Tubing U-bend (>3/4 in.)
Table 32: Radii of Coiled Expansion Loops and Developed Lengths of Expansion Offsets.
Anticipated Linear
Expansion (LE) (inches)
1/2
1
1-1/2
2
2-1/2
3
3-1/2
4
R = Centerline Length of Pipe.
1
Definitions
Physical Pipe Length: Actual length of straight segment(s) of pipe.
Equivalent Pipe Length: Actual length of pipe plus equivalent lengths of long radius elbows, Y-branches, and valves.
Layout Procedure
1. Draft a one-line diagram of the proposed piping system connecting outdoor unit to indoor units. Follow the pipe limitations listed on the
previous page.
2. Calculate the physical length of each pipe segment and note it on the drawing.
3. Calculate the equivalent pipe length of each pipe segment.
Using Elbows
Field-supplied elbows are allowed as long as they are long radius and designed
for use with R410A refrigerant. The designer should be cautious with the quantity
and size of fittings used, and must account for the additional pressure losses in
equivalent pipe length calculation. The equivalent pipe length of each elbow must
be added to each pipe segment. See the table for equivalent lengths.
56 | REFRIGERANT DESIGN
50°
55°
60°
65°
70°
0.06
0.06
0.07
0.08
0.08
0.12
0.13
0.14
0.15
0.16
0.18
0.20
0.21
0.23
0.24
0.24
0.26
0.28
0.30
0.32
0.30
0.33
0.35
0.38
0.40
0.36
0.39
0.42
0.45
0.48
L
1/4
R
6
1
L
38
2
R
9
1
L
54
2
R
11
1
L
66
2
R
12
1
L
77
2
R
14
1
L
86
2
R
15
1
L
94
2
R
16
1
L
102
2
R
17
1
L
109
2
L = Centerline Minimum Radius (inches).
2
Due to our policy of continuous product innovation, some specifications may change without notification.
©
LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG " is a registered trademark of LG Corp.
Fluid Temperature °F
75°
80°
85°
90°
95° 100° 105° 110° 115° 120° 125° 130°
0.09
0.09
0.10
0.10
0.11
0.17
0.18
0.19
0.20
0.21
0.26
0.27
0.29
0.30
0.32
0.34
0.36
0.38
0.40
0.42
0.43
0.45
0.48
0.50
0.53
0.51
0.54
0.57
0.60
0.63
R
Loop
Nominal Tube Size (OD) inches
3/8
7
44
10
63
12
77
14
89
16
99
17
109
19
117
20
126
Table 33: Equivalent Piping Length for Piping Components.
Component
Long Radius Elbow (ft.)
0.11
0.11
0.12
0.13
0.14
0.22
0.22
0.23
0.26
0.28
0.33
0.32
0.35
0.39
0.42
0.44
0.43
0.46
0.52
0.56
0.55
0.54
0.58
0.65
0.70
0.66
0.65
0.69
0.78
0.84
L
Small Tubing U-bend (<3/4 in.)
1/2
8
50
11
70
14
86
16
99
18
111
19
122
21
131
22
140
Size (Inches)
1/4
3/8
1/2
5/8
0.5
0.6
0.7
0.15
0.15
0.29
0.30
0.44
0.45
0.58
0.60
0.73
0.75
0.87
0.90
3/4
9
59
13
83
16
101
19
117
21
131
23
143
25
155
26
166
3/4
0.8
1.2
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