Suction accumulator requirement

[biniljk]

Hello all,
As a part of my job I am came across many refrigerators. I have one very basic question here, what drives the requirement for an accumulator. I can see refrigerators with and without it. I hope your expertise will help me to understand better.

*Mods please guide me if a similar thread already exists.

Thanks

[Rob White]

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Suction accumulators are used to prevent liquid refrigerant
from entering the compressor. If you suspect you may have
liquid in your suction vapour, then you need a suction accumulator.

They tend to be used on reverse cycle systems, such as heat pumps
because when they go from cooling to heating and back to cooling they
can have liquid in places they don't want it and the suction accumulator
is there to protect the compressor.

They are also used on every rotor compressor, in fact they are built onto
the body of the compressor in the manufacturer stage because rotor
compressors will not tolerate any liquid back.

Regards

Rob
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[biniljk]

Thanks Rob. I didn't made it clear in my first post. There are refrigerators with and without accumulators near to Evap. So if liquid refrigerant entering compressor is the concern, then invariably all should have accumulators. So accumulator is put where the HE length is not adequate?. As per my understanding once refrigerant passes through heat exchanger, refrigerant goes to super-heat region.

[mikeref]

You have to define "Refrigerators." Are you talking about domestic or commercial?

[Rob White]

Thanks Rob. I didn't made it clear in my first post. There are refrigerators with and without accumulators near to Evap. So if liquid refrigerant entering compressor is the concern, then invariably all should have accumulators. So accumulator is put where the HE length is not adequate?. As per my understanding once refrigerant passes through heat exchanger, refrigerant goes to super-heat region.


The trouble is there is no one answer to fit all situations.

Some systems have suction accumulators and some don't.

It all comes down to the design and the designer.

One person might design them into a system as a precaution
whereas another designer won't.

If there is a real risk of liquid slugging, you are correct to say
a correctly designed system should have superheated vapour
only in the return, but if you run the risk of liquid being present,
even if it is a small risk, then suction accumulators remove the
risk to the compressor.

Regards

Rob

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[biniljk]

"Domestic Refrigerators" mikeref.

[biniljk]

Thanks Rob..Does accumulator got something to do with tropical regions?. Because most of India Brazil products I can see accumulator but US Canada doesn't have..

[Rob White]

"Domestic Refrigerators" mikeref.

I've never been to Brazil so I can't agree or disagree but I have
seen my fair share of domestics and I have never ever seen one
with a suction accumulator on.


Thanks Rob..Does accumulator got something to do with tropical regions?. Because most of India Brazil products I can see accumulator but US Canada doesn't have..

I can't see why it should be a tropical thing.

I live in England and we are part of Europe, parts
of Europe are tropical and I have never seen one yet.


Photos or it didn't happen :D

Photo one and post it so we can see.

Rob

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[nike123]

Are you sure that you are clearly distinguish between suction accumulator and liquid receiver. Also, In domestic fridges, those two are rarely seen, since domestic fridges are in general with capillary tube as expansion device, and critically charged, therefore, no need for accumulation. Usualy, I see suction accumulator on cappilary tube systems on AC rotary vane compressors, since they are directly fed to suction of compressor cylinder and housing is on high pressure side.
But, maybe I am wrong!;)

[salahzantout]

it depends on what type of system you have i think... different fluctuated (low ofcourse) heat load on evap, the possibility of getting dirt evap and so on.

Usually if your working on large scale refrigeration rooms an accumulator is a must to protect the compressor ( high cost of compressor ) and especially when a room is off for long durations. Note that you would have a long suction line distances and would condensate when system is off...might take place when on successive defrost cycle

What if there happened a leakage in pipings and ***** gets out of the system... you will have an iced evap and liqiud will flood back to compressor. what if defrost heater ( electric ) is burnt for some electric reason... you will again have an iced up evap and liquid floodback...

One more thing, suction accumulators is a must in low ambient areas...

many reasons could occur so it depends on how risky it is...

[Rob White]

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Its not a heat absorption fridge is it?

It does have a compressor?

Rob

.

[biniljk]

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Its not a heat absorption fridge is it?

It does have a compressor?

Rob

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Yes Rob one I am talking about is domestic refrigerator working on Vapor compression system ie with compressor.

[biniljk]

Are you sure that you are clearly distinguish between suction accumulator and liquid receiver. Also, In domestic fridges, those two are rarely seen, since domestic fridges are in general with capillary tube as expansion device, and critically charged, therefore, no need for accumulation. Usualy, I see suction accumulator on cappilary tube systems on AC rotary vane compressors, since they are directly fed to suction of compressor cylinder and housing is on high pressure side.
But, maybe I am wrong!;)
Sorry Nike123, I am not very families with term Liquid receiver? you mean capillary tube? Anyways accumulator I am talking about is b/w evaporator and heat exchanger.

[Rob White]

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Photos........

If you photograph one we'll know what we are talking about.

Regards

Rob

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[biniljk]

Rob, I don't have any pics handy..but think attached one will help..10804 will help

[nike123]

Anyways accumulator I am talking about is b/w evaporator and heat exchanger.
What heat exchanger you are refering, since evaporator is also heat exchanger?
What line is it mounted. Liquid or gas?

[biniljk]

What heat exchanger you are refering, since evaporator is also heat exchanger?
What line is it mounted. Liquid or gas?

Heat exchanger is after evap, that will make sure refrigerant will go to super heated region.
Accumulator is after evap, so refrigerant is in gaseous state.

[D.D.KORANNE]

If you need help in the seletion of suction accumulator , i can help !

[Rob White]

Rob, I don't have any pics handy..but think attached one will help..10804 will help

That is definitely a suction accumulator and now you have posted the picture
I instantly recognize them on the Frost free type evap. You are right some have
them and some don't. I have seen them in the UK and they are quite common.

Its all down to the design :D

Regards

Rob

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[Aria]

Hello All,

as i know, accumulator suction pipe is required to prevent compressor broken because of liquid sluging when the flow back to compressor.
But this is depend on analysis from each designer. The critical item in accumulator is inner volume.
Another case, that we must considered about accumulator is noise damper. we can use it in suction or joint pipe between discharge comp and condenser. :D

Regards,

Nice Sharing.

[mikeref]

Meh...Evaporator to compressor "accumulator" prevents liquid flood back to the compressor on start up.
Compressor discharge to condenser has a muffler on some domestic but mostly high volume systems in commercial and industrial designs for noise reduction.

[mjreefer]

on a small system with no reverse cycle I would suggest it is there more to meter oil return than liquid refrigerant