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1 1
A Modern Approach to Selecting Capillary Tubes
Andy Schoen
Manager, Technical Services Tecumseh Products Co.
2 2
Expansion Devices
3 3
Hand Expansion Valve
4 4
Short Tube Restrictor
5 5
Automatic Expansion Valve
6 6
Thermostatic Expansion Valve
7 7
Electric Expansion Valve
8 8
Capillary Tube
9 9
Capillary Tube Flow
Bubble Point
Flow
Low ∆P High ∆P
High to Low Side ∆P
10 10
Henry Ehrens
11 11
Lower Ambient Temperature
Bubble Point
Flow
Low ∆P High ∆P
High to Low Side ∆P
12 12
Higher Ambient Temperature
Bubble Point
Flow
Low ∆P High ∆P
High to Low Side ∆P
13 13
Supco Cap Tube Chart
14 14
J/B Cap Tube Chart
15 15
Cap Tube Sizing Problem
• Refrigerant R-134a • Medium Temp Cooler • 1/4 HP Compressor
16 16
Supco Cap Tube Chart
17 17
Compressor HP vs Rating
Model Btu/h
TPA0421YXA 2050
TPA9421YXA 2075
TPA9423YXA 2320
AEA9423YXA 2390
TPB9423YAA 2675
1/4 HP R-134a Commercial Temp Compressors
18 18
Supco Cap Tube Chart
19 19
Wolf and Pate Correlations
1995
2002
20 20
Characteristics Considered
• Capillary Tube Length and ID • Pressure (liquid and vapor) • Density (liquid and vapor) • Viscosity (liquid and vapor) • Specific Heat (liquid and vapor) • Surface Tension (liquid) • Amount of Subcooling • Latent Heat of Vaporization • Heat Exchange Length
21 21
Edgar Buckingham
22 22
Buckingham π Correlation
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121
321
21
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ππππ
ππππ
23 23
15 Different Parameters
24 24
Wolf and Pate 2002 Correlation
25 25
Characteristics To Determine
• Capillary Tube Length and ID • Pressure (liquid and vapor) • Density (liquid and vapor) • Viscosity (liquid and vapor) • Specific Heat (liquid and vapor) • Amount of Subcooling • Latent Heat of Vaporization • Heat Exchange Length
26 26
NIST Refprop
27 27
Tecumseh Web App Site
28 28
Capillary Tube Sizing Web App
29 29
Capillary Tube Sizing Web App
30 30
Capillary Tube Sizing Web App
31 31
Capillary Tube Sizing Web App
32 32
Capillary Tube Sizing Web App
33 33
Adiabatic vs Non-adiabatic
34 34
Heat Exchange Length
35 35
Heat Exchange Length
36 36
Why use heat exchange length?
37 37
Web App Selection using HP
38 38
Supco Cap Tube Chart
39 39
Web App Selection using HP
40 40
R401A Selection using HP
41 41
R401A Selection using HP
42 42
R401A Selection using HP
43 43
TPA9423YXA
44 44
TPA9423YXA Selection at AHRI CBP
45 45
TPA9423YXA
46 46
TPA9423YXA Selection @ 25°F/110°F
47 47
Cap Tube Selection using Comp Model
48 48
Cap Tube Selection using Comp Model
49 49
Cap Tube Selection using Comp Model
50 50
Cap Tube Selection using Comp Model
51 51
Supco Cap Tube Chart
52 52
Cap Tube Selection using Comp Model
53 53
Cap Tube Chart using Btu/h
54 54
Questions?