Minimum discharge pressure

[DKov]

We have Sabroe 163 HF and 163 HM units (Ammonia). They are about 15 years old and have the original separators on them. We would like to reduce the condensing pressure for energy reduction purposes.
I was hoping to condense at 20*C in winter.
Liquid lines are pumped.
Can anyone help me as to what the minimum pressure is to ensure good oil separation.
Is poor oil separation likely to cause damage or just reduce system performance?

[Lc_shi]

if the oil separation is by the pressure diff ,there would be a minimum pressure difference. The calalogue should provide.

regards
LC

[Sergei]

We have Sabroe 163 HF and 163 HM units (Ammonia). They are about 15 years old and have the original separators on them. We would like to reduce the condensing pressure for energy reduction purposes.
I was hoping to condense at 20*C in winter.
Liquid lines are pumped.
Can anyone help me as to what the minimum pressure is to ensure good oil separation.
Is poor oil separation likely to cause damage or just reduce system performance?

Just test your plant. Additional oil in the system (due to low condensing pressure) will not cause the damage and will not reduce system performance. You just have to drain the oil more often.

Sergei

[US Iceman]

Can anyone help me as to what the minimum pressure is to ensure good oil separation.

The minimum pressure depends on several areas. One of these is the oil separator size. When the discharge pressure decreases, the oil separator velocity will increase (unless you unload the compressor). At full load and low discharge pressure, the oil separator effectiveness decreases and contribute to excessive oil carryover.

You need to ask the manufacturer what minimum discharge pressure is acceptable (at full load).

Or, you can slowly reduce the pressure in small increments and observe the oil levels in the crankcases.