Refrigerant Capillary Tube Calculator
Calculate capillary tube dimensions for refrigeration systems
Capillary Tube Resizer
Typical range: 1-6 meters
Typical range: 0.5-2.28 mm
Desired diameter for new application
Calculation Results
Formula: New Length = Original Length × (New ID / Original ID)^4.6
Application: Refrigeration and air conditioning systems
Design Validation
Consider adjusting the diameter to be within the typical range for optimal performance.
Tubes too short may cause deflection issues, while tubes too long may cause excessive pressure drop.
Example Calculation
Capillary Tube Resizing
Problem: Replace a 3.5 m tube with 1.5 mm diameter with one having 1.3 mm diameter
• Original length: 3.5 m
• Original diameter: 1.5 mm
• New diameter: 1.3 mm
Solution
New Length = 3.5 × (1.3/1.5)^4.6
New Length = 3.5 × (0.867)^4.6
New Length = 3.5 × 0.518 = 1.81 m
Result: The new tube should be 1.81 meters long
Typical Specifications
Capillary Tube Functions
Controls refrigerant flow rate to evaporator
Reduces refrigerant pressure from high to low side
Maintains pressure difference in system
Enables proper evaporation at desired pressure
Simple, reliable expansion device
Understanding Capillary Tubes in Refrigeration
What is a Capillary Tube?
A capillary tube is a copper tube with a very small internal diameter (0.5-2.28 mm) and considerable length (1-6 m) used in refrigeration systems as an expansion device. It controls the flow of liquid refrigerant from the high-pressure side to the low-pressure side.
How It Works
- •High-pressure liquid refrigerant enters the tube
- •Pressure drops due to friction and small diameter
- •Flow rate is controlled by tube dimensions
- •Low-pressure refrigerant enters evaporator
Resizing Formula
NL = OL × (New ID / Orig ID)^4.6
- NL: New length of capillary tube
- OL: Original length of capillary tube
- New ID: New inside diameter
- Orig ID: Original inside diameter
Important: The 4.6 exponent is based on the relationship between tube diameter and flow resistance in capillary tubes for refrigerant flow.
Design Considerations
Too Short
- • Higher flow rate
- • Risk of deflection
- • Bending stress issues
- • Poor pressure control
Optimal Length
- • Proper flow control
- • Adequate pressure drop
- • System efficiency
- • Reliable operation
Too Long
- • Excessive pressure drop
- • Reduced flow rate
- • Poor system performance
- • Space constraints