r600a or 134a

[Minestrone Dave]

I have done a deal on a pallet of 134a compressors, 1/6 to 1/4hp. Do you think i could replace failed r600a fridges with a new 134a compressor, drier, and gas ?:)

[taz24]

I have done a deal on a pallet of 134a compressors, 1/6 to 1/4hp. Do you think i could replace failed r600a fridges with a new 134a compressor, drier, and gas ?:)


I'm not sure it would.

At -10degC 600a suction is just over 1b and 134a is 2b.
At 30degC discarge is 600a about 4b and 134a is nearly 8b.

I don't think the cappilary will be suitable.

taz.

[Minestrone Dave]

Thanks Taz. It was worth asking.

[taz24]

Thanks Taz. It was worth asking.


R409a is one refrigerant that was recomended to me as a replacement for 600 and I have used it.
On a chart it does not look right but in the fridge - freezer it worked a dream.

Cheers taz.

[Minestrone Dave]

Thanks Taz, im off to buy some :D

[chillin out]

I have used R134a several times with success.

Replace filter drier and remove just less than half of the capillary and it should work OK.

Chillin:):)

[Igor]

I need to fill a domestic freezer with R600a but not sure of this refrigerants availability. Can an R600a compressor be retrofitted to a HFC gas and which gas in this case?

[TXiceman]

R600a is also know as isobutane. The problem with butane is the low discharge superheat and the inability to heat much on compresion. R600, normal butane has a vapor dome (P-H diagram) that skews over to the right and the ideal compression line will go back into the dome which indicates it is possible to have liquid refrigerant develop in the compression cycle. The way to avoid this is to superheat the suction 30 or 40 dF to get away from the vapor/liquid dome.

I do not have ready access to the R600a charts and can not confirm that that it is as bad as R600.

Generally where you see R600a used in small equipment, it is mixed with R-290 for better properties.

According to the SNAP charts, R600a is an acceptable replacement fro R12 and R134a.

Here is an interesting link of refrigeration...http://cibseashrae.org/presentations/dunsdon1205.pdf

Another article on http://cibseashrae.org/presentations/dunsdon1205.pdfalternates...http://cibseashrae.org/presentations/dunsdon1205.pdf

[shaltout]

Hi all,
My first post :)
I have a similar matter,
I have a domestic refrigerator designed for using R600a as a refrigerant.
I should use the same structure but with R134a as a refrigerant.
I would like to know what modifications I need to carry out on the cooling circuit.
I already know from the pervious posts that I should reduce the capillary tube length (or increase the inner diameter) to increase the flow rate.
Surely I will also need to change the compressor to another one with the approximately same cooling capacity at the same evaporation temperature in order to maintain a reasonable compressor operating rate.
Also the filter dryer will need to be changed to be compatible with R134a.
What I do wonder about will I need any other modification in the rest of the system such as the evaporator or the condenser.

another issue
If R600a is replaced with R134a
What materials that might be compatible with R600a and can be not compatible with R134a, for example I knew that natural rubber is not compatible with R600a but it's with R134a.

I know it was a long post but there is still one last thing

If any of you do have a research reference paper or some institute recommendation in that matter it would be most welcome.

I have already searched in some major compressor manufacturers such as ACC, Danfoss and Embraco and i found nothing

currently I am searching in phase out websites looking for a dropin replacement paper in the matter.

Many many thanks for being patient and reading all my post.

waiting for your replies :)

[chillin out]

How many times do you plan to do this procedure?
It sounds like you are planning to do quite a few of them?

Changing R600a to R134a by cutting down the capillary is an emergency type job, why would you want to do it properly by changing the compressor?

Chillin:):)

[thebigcheese]

have replaced r600 several times with r134a and has worked away ok

[shaltout]

Hi again,

I am working in a domestic refrigerators manufacturing plant,
we did get another manufacturer refrigerator design through co-operation between us, it was originally made to use R600a
but here in Egypt R134a is still in use and generally any manufacturing plant intended for making R600a refrigerators will need special equipments and levels of safety which our plant doesn't support
So we need to modify the design to use r134a.
that's why is was asking for a paper about drop in replacement of r134a with r600a
I will carry out what's in the paper but in the opposite way.
for example if the paper says make the capillary shorter I will make it longer and so on.

Thanks all :)

regards,
Osama Shaltout

[chillin out]

Ahh got you now, I didn't think this was going to be a one off job.

I do not think that there are any guidelines down in paper saying how to retrofit R134 to R600 (or even the other way round).
It's just going to be a case of 'suck it and see'

Trial test a couple and then modify if the need arises.

Chillin:):)

[TXiceman]

I don't think you will find a paper telling you how to make the conversion. This is something that you will have to research and develop. Probably need to start by hiring a consulting engineer to develop the procedure and run some test if you can not do this in house.

Ken

[old gas bottle]

also replaced a 600 comp with a 134a on many occasions years ago and never had a problem.;)

[icecube51]

Yo guys,
if jou want to mess around whit the cappilairs,there is a nice small program cold " Dancap ", its free and avaleble on the Danfoss site. i already tryed it and its really nice.

Ice

[shaltout]

Hi all,

my manager have found a paper in his old stuff
it is a paper published by Electrolux compressors ( at least when it was called that )
it's a bit simple and short but for now it will do

find it attached

Regards,
Osama Shaltout