Refrigerant Line Set Sizing

Size suction, liquid, and hot gas lines based on capacity, refrigerant, length, and rise.

Total system cooling capacity in tons of refrigeration.
tons
Refrigerant type affects density, velocity requirements, and pipe sizing.
Total equivalent length including fittings. Add 50% for fittings if unknown.
ft
Height difference between evaporator and condenser. Affects oil return in suction lines.
ft
Suction lines sized for velocity and pressure drop. Liquid lines sized for pressure drop. Hot gas for velocity.

Results

Recommended Line Size:
Nominal copper tube OD for ACR tubing.
-in OD
Estimated Velocity:
Gas velocity in the line. Suction: 900-4000 FPM for oil return. Liquid: 100-500 FPM.
-FPM
Pressure Drop:
Estimated pressure drop. Keep suction line drop equivalent to less than 2F sat temp change.
-psi
Oil Return Check:
Suction lines must maintain minimum velocity for oil return, especially on vertical risers.
-
Reference: ASHRAE Refrigeration Handbook Ch. 1-2. Copper Development Association refrigerant piping guides.