View Full Version : Saturation pont

01-02-2017, 08:20 PM
Dear Guys,

As you know at receiver tanks (for example R22) are under liquid and gas situation. By this we can tell this is saturation point. Also at R22 cylinder we have both of liquid and gas.
Also at cylinder can we suppose that it is also under saturation point same as receiver tank or it is mistake ?

Sincerely yours.

01-02-2017, 09:17 PM
Think this has been asked before.
Answer was something like in a static system it's like a cylinder. In a running system however saturated bit is at the top and a bit subcooled down the bottom.

Probably get a few different answers but that's how I recall the general answer.


02-02-2017, 06:07 AM
Thanks for your prompt reply Andy.
My question was about R22 cylinder, But anyway at receiver tanks when we have both of gas + liquid of R22 inside, sub-cooling has not meaning. Because we can't be in both of saturation point and sub-cool area at same place.

My question still is about cylinder ofcourse.

Rob White
02-02-2017, 08:27 AM

In a cylinder, as long as there is liquid present the refrigerant is saturated.

The receiver is another thing altogether. When a system is off the receiver
is just a glorified cylinder and the refrigerant is saturated (as long as liquid is present)
but if the system is running, the properties of the refrigerant inside the receiver
have caused arguments for decades and will always cause arguments.



03-02-2017, 07:03 PM
The question is always to know if the receiver (or separator or cylinder) is at a stable condition or a dynamic one (naturally not stable).
When the systems are working there is always some level of instability and so it is possible to have sub-cooled liquid in contact with super-heated gas (or one of them saturated and the other sub-cooled or super-heated respectively). When we have one of this conditions some saturated liquid evaporates with the super-heated gas and some saturated gas condenses with sub-cooled liquid, the sum of all of this changes makes the interior of the systems very active and changing all the time.
As it is difficult (or impossible) to take in consideration all those changes we have the tendency to consider and make calculations as if the situations were all stable at the nominal conditions, that's why sometimes it is said that in the reservoirs and in the separators the liquid and the vapour are at the saturated condition.