Oil Separators

[Samarjit Sen]

I would like to know if it is essential to install an Oil Separator for a system with R 22 and an Evaporation Temperature of - 5oC.

Thank you.

[yangchenchen]

it is not essential. to my knowledge ,a refrigeration system with R22 and an evaporating tem of - 15oC.it is essential to use an oil seperator

[vadivelan]

The Miscibility of mineral oil with R-22 is not great particularly at low temperatures. But I feel for -5degc Evaporating there is no need for oil separator. If you have an option of POE inplace of mineral oil it will be much better.

[Samarjit Sen]

Could I please have some document so that I can produce the same to the client.

[US Iceman]

If you are using a screw compressor, oil separators are mandatory Samarjit.

If a recip. compressor is used I think you are not required to use an oil separator as long as the suction lines are designed properly.

[Samarjit Sen]

These are all reciprocating Semi Hermetic Compressors. I had designed the pipe line with due care and on the basis of the pipe line datas available in the Carrier Handbook. Further there is no oil return problem in any of the compressors, except one. There are in all 6 water cooled condensing units.

The plant has been operating for the last about a year and there has been no problem. The temperatures and the Humidity are being maintained as per requirement. Now the party has called a technician for undertaking the maintenence of the plants. He has told them that the plant should have Oil Separators. Further we had put PHEs as Condensers. The technician says that these are meant for dairies and that we should have put Shell & Tube Condensers.

The problem is that although the plants are running properly and the customer is more than satisfied with the performance, but the technician who does not appear to be a person well versed in refrigeration has made some comments which the client is believing more than our comments. These are the biggest troubles we have here. These technicians here in our country do not need and basic qualifications to start working on refrigeration plants. Gradually over the years they will be known as engineers and start taking up designing and projects.

With best wishes and a Happy & a Prosperoud New Year,

[PaulZ]

Samarjit Sen
We have used PHE's as condensers on NH3 plants with no problems as long as the cooling water is kept clean and the strainers are adequate.
With R22 at chilller duty there is no need to have oil separators. All the Carrier water chillers on R22 that I have worked on don't have any and these chillers don't have problems with oil return. Once the oil / refrigerant mix is right the oil moves around the system with no problems.
It sounds like the technician has nothing to do and is trying to get some extra work.
If the client wants proof show him some schematics of Carrier chillers.
Paul

[Josip]

Hi, Samarjit Sen :)




The plant has been operating for the last about a year and there has been no problem. The temperatures and the Humidity are being maintained as per requirement. Now the party has called a technician for undertaking the maintenence of the plants. He has told them that the plant should have Oil Separators. Further we had put PHEs as Condensers. The technician says that these are meant for dairies and that we should have put Shell & Tube Condensers.

The problem is that although the plants are running properly and the customer is more than satisfied with the performance, but the technician who does not appear to be a person well versed in refrigeration has made some comments which the client is believing more than our comments. These are the biggest troubles we have here. These technicians here in our country do not need and basic qualifications to start working on refrigeration plants. Gradually over the years they will be known as engineers and start taking up designing and projects.

Sounds like a SF story, unfortunately it is true....Not easy to suggest you what to do except to stand behind your project design....seems he would like to make some extra money...


It sounds like the technician has nothing to do and is trying to get some extra work.
If the client wants proof show him some schematics of Carrier chillers.

You are a smart man and you can handle the guys like him;)

Best regards, Josip :)

[hendry]

Hola Samarjit,

i believe
1] screw comp need oil sep;
2] piston comp varies in accordance with design.

i've designed psiton comp package unit without oil sep and it still works fine.

but, to me most multiple comp in centralised system need oil sep & tank to re-distribute lube oil to each comp, esp. when lead-lag ctrls to comp occurs.

i don't know which version of carrier handbook you seek reference but it would be better to review more than 1 reference/s.

yes, on the piping design, i wonder you have also consider the pressure losses over pipe fittings and valves ...

there are many factors within the piping system which could induce velocity losses in lube oil travelling during its balancing cycle. i also take deep considerations on equal distribution in centralised piping.

[Samarjit Sen]

Hello Hendry,

I was referring to the Carrier Handbook of System Design. Although I have some more reference books and references for refrigeration piping, I have always preferred this particular Handbbook.

The systems are all independent and there is no problem as such. The required conditions are being maintained properly and the client is satisfied with the performance. It is just that a technician has advised them certain modifications and requirements.
and unfortunately the owner has been greatly infuenced by the so called engineer.

This is the first time that such a thing has happened to me and I felt very bad about the same. As I feel that if I share my experience and my tragidy like this with you all in the forum, I shall feel not greatly relieved but will gain some knowledge if by any chance there has been an error on my part.

For all of us this Forum is a great place to share and give. From the comments recieved by my freinds , I am greatly relieved and am more in peace.

[hendry]

well, friends [sometimes foes] are blessings to us.

i think i have the same book when i was in building jobs. [have to dig the old boxes to find it ...] i still remember most consultants will have one in their drawer. they refer nothing but this for air cond design those days ...

agreed, some client's maintenance team just not the right stuff for the jobs but yet blow big horns ...