New project -> -100*C CO2 AutoC

Printable View

Show 100 post(s) from this thread on one page

08-23-2006, 11:58 AM
LukeXE

New project -> -100*C CO2 AutoC

Hey !

I thinked about building a cascade for my usage, very low temp cascade, but I`ve got some problems with builidng it (don`t have second compressor ite.).

I like autocascades very much, they can be small, quiet (my rotary isn`t loud) and does nice temps :toast:

I`ve got acces to CO2, it`s very cheap and it`s only low stage gas I can get...so I will try to build autocascade, that will do -100*C idle with CO2. My previuos one did -94*C, close, very close, but not -100*C.

I wanna project autocascade, that will hold 150W load at -70*C, I will do it slow and clean...I wanna make nice unit, the nicest I ever build.

So, lets start:

http://gorajec.net/lukexe/LT%20autoc.../ak-scheme.jpg

3 SLHX, without an oil sep, I don`t think that it will be helpfull, oil will go with propane and will stop in phase separator.

Probably I will put captubes into suction lines to improve subcooling, I will use plate HX as main HX, SLHX will be pipe in pipe heat exchangers.

So, that`s all for that momment, some progress I will show tomorrow, I will buy condenser, wooden plate for whole unit, some pipes and insulation for everything.

Stay tunned :)
08-23-2006, 12:11 PM
eshbach

looks like a good project... quite a few heat exchangers there. :p:

i'm going to test-charge my competition autocascade with CO2 this weekend... i'm hoping for very similar numbers.

by the way, you can type a ° symbol in your paint program by holding ALT and typing 0176 on your number pad (and then releasing ALT). :)
08-23-2006, 12:25 PM
LukeXE

THX, I changed that symbol, thanks once again :)

Test, test your auto-c, I hope you will have nice idle/load temps.
08-24-2006, 02:35 AM
404Power

RLY nice looking project Luke! :)
I also hope that you can reach your -70°C loaded you pointed at! ;)
btw.: is this your 3rd or your 4th auto? ^^ :)
08-24-2006, 02:43 AM
SoddemFX

With the first SLHX on the entry to the phase separator, wouldnt you risk condensing CO2 also? Just a question, i dont know the answer myself :)

Tom
08-24-2006, 02:44 AM
Unknown_road

the most left HX will heat up the liquid CO2 unless you have serious floodback ;)
08-24-2006, 05:36 AM
ak_47_boy

dosen`t co2 freeze at -79?
08-24-2006, 05:49 AM
aasmaukr

ak_47_boy: CO2 freezes at -78.5° C at atmospheric pressure, but in a vacuum it's freezing point becomes lower so it's possible to reach -100° C (and even lower).
08-24-2006, 07:34 AM
LukeXE

Quote:

Originally Posted by 404Power

RLY nice looking project Luke! :)
I also hope that you can reach your -70°C loaded you pointed at! ;)
btw.: is this your 3rd or your 4th auto? ^^ :)

THX :)

It`s my 4rd auto-c :D :D

Quote:

Originally Posted by SoddemFX

With the first SLHX on the entry to the phase separator, wouldnt you risk condensing CO2 also? Just a question, i dont know the answer myself :)

Tom

Hmmm...some of CO2 will condense...and I want it :) Why ? I will have much lower temp at main HX, so on evap temp will be much lower too.

For example :

That same parts, compressor, condenser, SLHX and some more parts:

Without HX before phase sep (At 155W load):

HX -> - 20*C // Evap -51*C

With HX before phase sep (At 155W load)

HX -> -33*C // Evap -62*C

Quote:

Originally Posted by Unknown_road

the most left HX will heat up the liquid CO2 unless you have serious floodback ;)

I know that, I will try to have big floodback to flush that hx well.
08-24-2006, 07:41 AM
Unknown_road

Ok, but I still don't see the use of it, especially since your using a plate HX.
08-24-2006, 08:51 AM
LukeXE

http://gorajec.net/lukexe/LT%20autocascade/P1010463.jpg

http://gorajec.net/lukexe/LT%20autocascade/P1010464.jpg

For high stage, I hope it will work well, better than captube :D

About that SLHX...I think I will not use it, 2 slhx will be good at least.
08-24-2006, 11:44 AM
Marvin_The_Martian

You're working on the wrong unit there ;)

J/k looking good luke :thumbsup:
08-24-2006, 12:28 PM
LukeXE

On saturday I will have captube for cpev and whole unit will be done, your unit ;)
09-03-2006, 12:19 PM
LukeXE

so, little update ! (without picks, they will be tomorrow :) )

I won`t use this txv, it`s too expensive for me, I will use my sweet captube :D I won`t use plate HX too, because it`s too big, I`m using now pipe in pipe heat exchanger, I think it`s should work well.

So, unit is done, pressure tested and I did tripe evac today, now it`s charged with co2 (40PSI).

It`s black, good looking, two SLHX, one before phase separator, one on R290 liquid line after separator.

Tomorrow some picks, now I must buy some insulation for it, because it`s naked :)
09-03-2006, 12:28 PM
n00b 0f l337

Woot this should be the best autocascade up to date. Just wait for the ownage. :)
09-03-2006, 12:33 PM
Xeon th MG Pony

I'd be worried about the level of super-heating your adding to the suction side and I think by the third Heat Exchanger you may actually be hurting your out going temp. Other then that looks great.
09-03-2006, 12:41 PM
LukeXE

Quote:

Originally Posted by Xeon th MG Pony

I'd be worried about the level of super-heating your adding to the suction side and I think by the third Heat Exchanger you may actually be hurting your out going temp. Other then that looks great.

you`re right about that third SLHX, that`s why I don`t use it :)

I can`t wait to show photos ! :toast:
09-03-2006, 01:22 PM
Brettbeck

I want to see it:D!

So is there no need for an oil sep in any auto-cascade?
Will the oil not freeze as long as it has a gas like R290 to carry it?
09-03-2006, 04:03 PM
sl4ck

Well........ :eek: :eek: i've been out from XS(no time :(), and when i get back i see that amazing project, i'm so excited to see pics as some results ;) Luke you´re "becaming?"(don´t know if it's the right term or if exists :D ) an Auto-C Pro :toast:
09-03-2006, 10:50 PM
LukeXE

some photos, As I promised !

http://gorajec.net/lukexe/LT%20autocascade/PICT9306.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9307.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9308.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9309.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9310.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9311.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9313.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9314.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9316.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9317.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9318.jpg
http://gorajec.net/lukexe/LT%20autocascade/PICT9319.jpg

Unit is ready to insulate and charge, I will do few tests without insulation.

don`t pay attention on leavings of armaflex on suction accumulator and on phase sep, I will insulate it one more time.

Do you like it ? :toast:

Quote:

Originally Posted by Brett

I want to see it:D!

So is there no need for an oil sep in any auto-cascade?
Will the oil not freeze as long as it has a gas like R290 to carry it?

That`s right, oil will go with R290 thru phase sep, HX, and will go back to the compressor.

thank you guys for nice words ! :toast: :woot:
09-03-2006, 11:33 PM
n00b 0f l337

You have no idea how I love it. :)
09-04-2006, 12:21 AM
Hugo van Dijk

Awesome work Luke, that auto-c really looks good.

Can,t wait to see what you can get out of it :D
09-04-2006, 12:26 AM
kayl

lukeXe i think ya started to take over berkuts job of cool new idears since he hasnt been around of late;)
cant wait to see results man.
09-04-2006, 12:38 AM
Brettbeck

Quote:

Originally Posted by sl4ck

Well........ :eek: :eek: i've been out from XS(no time :(), and when i get back i see that amazing project, i'm so excited to see pics as some results ;) Luke you´re "becaming?"(don´t know if it's the right term or if exists :D ) an Auto-C Pro :toast:

I think the word you are looking for is 'becoming' :D.

Looking good Luke! It will be interesting to see the results :).
09-04-2006, 03:19 AM
LukeXE

Tomorrow big day :D Today I don`t have time :(

Show 100 post(s) from this thread on one page