minimum fluid velocity in small refrigeration systems 1

[subjectin]

Considering a basic, relatively small (1/5 ton) condenser/txv/evaporator/compressor refrigeration system, does any standard for the minimum refrigerant fluid velocity for compressor oil return exist? The tubing would be copper with diameters less than 3/8" OD. I can locate the rule of thumb of 1200 feet per min for large industrial systems with large piping rises, but I have been unsuccessful in locating any such info for small systems.

Thanks for any info.

 

[HLH]

Suction lines for medium temperature (>20 deg F suction) applications should be sized for a minimum velocity of 500 FPM and a maximum velocity of 4,000 FPM for horizontal runs. The minimum velocity of vertical risers is 1,500 FPM. Where your velocity will fall depends on how much pressure drop the system can take without overtaxing the compressor. Pressure drop should be less than 3 psi/100 ft of pipe.