Recommended Lengths for Capillary Tubes
In this article, we explore the recommended lengths for capillary tubes with a diameter of 0.039 inches for freezing applications at -20°C. We focus on low-capacity domestic and commercial refrigeration systems, specifically for compressors of 1/4 HP, 1/5 HP, and 1/6 HP.
1. Applications with 1/4 HP
Refrigerant and Lengths:
- R134a: 1.18 m
- R600a: 1.36 m
- R404a: 1.41 m
- R290: 3.22 m
2. Applications with 1/5 HP
Refrigerant and Lengths:
- R134a: 1.49 m
- R600a: 1.71 m
- R404a: 1.73 m
- R290: 2.00 m
3. Applications with 1/6 HP
Refrigerant and Lengths:
- R134a: 2.12 m
- R600a: 2.39 m
- R404a: 3.28 m
- R290: 5.42 m
General Observations
Relationship Between Refrigerant and Length:
- R134a requires the shortest lengths.
- Followed by R600a, R404a, and finally R290, which always needs the longest length.
Importance of Adjusting Length:
- Ideal capillary tube lengths are approximately 2 meters.
- If the required length is significantly longer, adjusting the capillary diameter is recommended.
Compressor Power and Length Relationship:
- As compressor power (HP) decreases, the capillary tube length increases.
- This occurs because lower power requires better refrigerant flow control, achieved by increasing the capillary tube length.
