My 1st cascade R22/CO2

[Big SturL]

Get a new camera before you get a new compressor :P Haha, just kidding. The build is coming together nicely, keep it up

[LukeXE]

Bigger compressor means bigger cooling capacity

[andre X_X]

well, for now im not hoping very good result, its my first cascade, -70@200w is my target.... im just wanna finish it first, gain experience from it and then modify it...
thx for all your helps....

[LukeXE]

-70*C@200W with that compressor can be, very, very, very hard. If possible imho.

[andre X_X]

what temp should i expect with that compressor then? -60c @ 200w maybe?
changin to Daikin Rotary R22 3/4hp would be fine? its cheap here only $50

[ryba]

what temp should i expect with that compressor then? -60c @ 200w maybe?
changin to Daikin Rotary R22 3/4hp would be fine? its cheap here only $50

If you want -70*C @ 200W you must buy this compresor. With two rotary compresors your cascade will work fine.

[LukeXE]

That 3/4HP rotary would be much better option :-)

Hard to tell you how good results you can achieve with your small compressor, maybe -60C, maybe less, maybe more. But don`t think so that -70C

[andre X_X]

all right, time to save money .... for now i dont have other choice rather than using this 1/3 comp. need to learn how to play with this baby first before changing/adding some parts...

[andre X_X]

anyway, this is my 2nd stage comp datasheet....
what do you think?

[Big SturL]

270W at what temperature?

[kayl]

what temp should i expect with that compressor then? -60c @ 200w maybe?
changin to Daikin Rotary R22 3/4hp would be fine? its cheap here only $50

its hard to say with c02, unless you blend it correctly getting past -55c can be hard, -60's could be possible. Try what you have can always change the compressor later. I found 2 big rotaries makes -70c a little easier with c02.

270W at what temperature?

being its a r12 compressor id say its at -23c at 270w when using r12. so spec sheets dont mean much as we use different refrigerants with different boiling points.

[SoddemFX]

Being 12cc i think it will be fine for a "test" system

What are the test conditions the datasheet uses to get that 270W evaporating capacity on r12?

Tom

[andre X_X]

@tom: don't know tom, they dont mention it, but as kayl said, it was -23.3c @ 270w...

anyway, i decided to make a custom oil sep rather than buy it as i dont have enough money. the Alco A-W55877 with 7/8 OD is $65 but i have unused Dry ice container with 25cm height and 2" diameter, just need to make the top lid and adding steel wol . it'll save some money. btw, do i need to Prefill the custom oil sep?

[Moc]

btw, do i need to Prefill the custom oil sep?

That depense on how often you want to open the value for oil return and how big your sep is...
If you have the (correct) oil, fill 100ml or less, if you don't have, leave it out.

[andre X_X]

i dont know what the oil on my 2nd stage comp. so i think i'll just leave it out...
anyway, how many steel wol should i put in oil sep? 3/4 height of oil sep enough?

[andre X_X]

allright i've got an idea about putting a hx on 2nd stage, but not from suction line (slhx)... how if i put the discarghed line inside the main HX? so i'll buy 5/8 copper and put 2x 1/4", one from compressor and one from oil sep, would it be okay?

[LukeXE]

discharge line from compressor has temp around...+90*C, HX won`t handle it.

[SexyMF]

I am fixing (the electronics) of a small cascade system at the moment. In there build, the oil seperator uses capillary tube for the oil return.

[star882]

changin to Daikin Rotary R22 3/4hp would be fine? its cheap here only $50

Where do you find a compressor that cheap?

[ryba]

Where do you find a compressor that cheap?

probably from scrap yard

[andre X_X]

d@mn thats hot luke, reconsidering slhx now... anyway how many steel wol do i need to put in my oil sep?

i found the compressor in local store. daikin 1hp would cost me arround US$75. its a R22 compressor.

[LukeXE]

d@mn thats hot luke, reconsidering slhx now... anyway how many steel wol do i need to put in my oil sep?

i found the compressor in local store. daikin 1hp would cost me arround US$75. its a R22 compressor.

any amount of steel wool would be ok. Try to bend inlet pipe at the bottom like this:

[andre X_X]

can i make it like this?

[kayl]

dont use steel wool it just burns.
Better to use copper scrubs and and purge when brazing.

[SoddemFX]

Hi Kayl,

If you purge as normal but use a very high flow rate then it doesn't burn. Steel is very reactive at high temperature, much more than copper, this is why you need to have a much more inert environment which you'll get inside the tube from the higher flow rate of nitrogen/whatever

But yes, if you dont/can't purge at all then steel wool will turn to black burned dust very quickly in brasing like you said

Tom