Refrigeration Pipeline Design, Pipe Size Calculation, Oil Return Slope & Support
Refrigerant pipeline includes discharge line, liquid line, suction line; improper sizing causes excessive pressure drop and poor oil return. Suction line design is the most critical: pressure drop directly reduces compressor capacity, slope toward compressor for oil return. Standard oil return slope for suction pipe: 0.5–1% downward gradient to compressor; horizontal pipe cannot level or reverse slope. Vertical suction riser needs oil trap (U trap) for low speed oil carry; single riser over 3m must design oil trap. Liquid line pressure drop control: avoid flash gas before expansion valve; flash gas reduces effective cooling capacity severely. Xiteliduo pipeline adopts seamless copper tube for fluorine refrigerant, stainless steel pipe for high pressure CO₂ system. Pipe support: use thermal isolation hanger for cold suction line, prevent heat bridge and condensation dripping on building structure. Suction line insulation: closed cell rubber foam insulation, vapor barrier jacket to stop moisture penetration and ice formation. Different circuit pipes mark color and tag: red discharge, blue suction, green liquid line for easy identification. Refrigeration maintenance & repair company checks oil trap and slope after long time running, avoid oil logging in low point.
FAQ
- What is the required slope of horizontal suction pipe? 0.5–1% down to compressor for oil return.
- What device is needed for vertical suction riser? Oil U trap.
- What will liquid line excessive pressure drop produce? Flash gas before expansion valve.
- What material for fluorine refrigerant pipeline? Seamless copper tube.
- What pipe material for CO₂ transcritical system? Stainless steel pipe.
- Why suction pipe hanger need thermal isolation pad? Cut heat bridge and prevent condensation.
- What insulation material for suction line? Closed cell rubber foam.
- What risk if suction pipe slope reversed? Oil accumulates in pipe, oil return failure.
