LukeXE`s autocascade for Xtreme Competition

[LukeXE]

Hey

I wanna show you my autocascade, that I have done for Xtreme 2006 Autocascade Competition. I`m in CO2 division, so I have hard job to do with that gass.

Now spec of unit:

Compressor -- Rotary 1HP
Condenser -- steel, about 2kW
Evap -- a`la chilly1 one, made in poland
Cap tube lenght -- high stage 2,35m, low stage 3m
Interstage HX -- my innovative project, insulated well with foam.
Phase Separator -- modded empty mapp gas bottle.
Gasses -- R22/R290/CO2
Cut off switch from Hatemi

and here some picks:















That`s all for now, tomorrow I will try to tune it well with 150W dummy load

Cheers !

[n00b 0f l337]

Whats your lowside pressure?

[LukeXE]

~ 1 bar, so really I must tune it to make pressures smaller.

[n00b 0f l337]

Still for 1bar doesnt that seem like the evaporator is too warm... I think your getting some r22 in the evaporator, the propane is lighter after all.

[LukeXE]

I wanna install fans that will blow on phase sep to make it colder a little bit , maybe it will help with good separation

[n00b 0f l337]

I doubt it, does the top of your phase seperator have a way to block liquid?

EDIT: Maybe provide more cooling (preferably sub ambient - SLHX sorta? ) to the mixture before it enters the phase seperator.

[LukeXE]

No, It doesn`t.

I will try do something to make it working good, but sth like slhx on pipe that enters to the phase sep isn`t good (I could be wrong), because if there will be too low temp, co2 will condense too. Maybe very, very small HX will be good

[n00b 0f l337]

Then look for a spot down your suction where its cold, but not cold enough. I don't think CO2 condensing would be a problem because I don't think you'll manage that that early.

[LukeXE]

I`ll add it today or tomorrow, small HX before phase sep, but now I must use R290 because I don`t have now any R22

[[XC] gomeler]

r290 and CO2 seems like a good mix, especially with r290's tendancy to carry oil Looks good though, I love the huge blog of insulation.

[LukeXE]

I have added a SLHX before phase sep, vacuuming now Maybe now high stage refrigerant won`t go to the evap...I hope

I have small problem because I don`t have R22 and R290 now ;( and I`m still waiting for preso from Hatemi, it`s should be in my house in next 2-3 days

[Brettbeck]

Looking good Luke. So if you use Co2 as a refrigerant how do you prevent it from forming dry-ice?

[LukeXE]

The CO2 tripple point is -56,6*C at (from what I read) 5 bar pressure (I`m not sure about that).

But now I don`t have any problems with dry ice, I hope I won`t have any

The one solution is to feed evap with high stage gas, that will flush the dry ice from evap.

[Brettbeck]

So the high stage gas would be the R290 that has run through the HX?

[LukeXE]

That`s right

you can just add second cap tube to the evap, one with co2 and one with R290.

[sl4ck]

where come from the cap with r290 that feeds the evap?
This won´t steal performace from the HX low stage ?

[LukeXE]

That cap goes from that same place, that goes cap tube to the HX (High stage liquid side).
And you think good, this will steal performance from HX, so I won`t use this method.

Today at 14 I will have package with cut-off switch and ethylene I will install it and make some photos

[sl4ck]

That cap goes from that same place, that goes cap tube to the HX (High stage liquid side).

so it has to be tunned like a dual head?

[Brettbeck]

I dont know if it would need to be tuned as all it would be doing was preventing dry-ice from forming...so it wouldnt matter how much was flowing through. Someone correct me if im wrong!

[kayl]

so ya getting some ethylene hey.
cant wait to see the results hey

[LukeXE]

I`m wondering, maybe I will use that ethylene in that auto-c, but really I don`t know how it will work Kayl, Have you used ethylene in your previous auto-c ?

[hatemi]

It worked pretty good. 1.7hp and 34cc tough IIRC 180w in the -70c range with half of the compressor under ice because too cold suctiongas

[LukeXE]

Hm, so maybe I will charge with that gas...I hope there is enough gas for that auto-c and cascade

BTW, What discharge pressure did you have ?

[hatemi]

It did have high startup preasure but when running properly it was quite reasonable. You might want to try with butane and propane to get the startup preasures lower. I was going to, but got bored before that

[jinu117]

Don't think you can lower starting pressure too much on mixed gas really without sacrificing temp too much. After all, the the high pressure gas is non condensable till quite a bit later :P