Experimental Single Stage

[_HL4E_HalfLife_]

I had an idea for a single stage system that works kinda like a cascade and i decided to build it and see how it works.

The compressor is 1/4hp 2600Btu's. The HX is 4 feet of 3/16 inside of 3/8 and ill be using 290 to start with and if all goes well ill add some Co2 to try to improve temps.

[jinu117]

Sounds like autocascade you are thinking of... :) Good luck

[_HL4E_HalfLife_]

Sounds like autocascade you are thinking of... :) Good luck

Hehe i knew someone would bring autocascade up lol but no this is not one of them.

[Nyx]

Drawings of the layout? A tiny peep of its concept pls :D

[runmc]

Drawings of the layout? A tiny peep of its concept pls :D

Just what I was thinking.:D
What you got up your sleeve??:confused:

[_HL4E_HalfLife_]

LOL you guys are like a bunch of kids wondering where all the chocolate eggs are hidden on easter, You can't stand not knowing what im up to lol. You'll all just have to wait till i update the project;) .

[Waus-mod]

Ok :D so when is the update?

[Gray Mole]

Sounds like either...

1. Using a slhx to boost condensing efficiency so that the co2 will condense more effectively in the captube or whatever system you use.

or

2. Using a dual evap based system where the second captube feeds a heat exchanger that's used to condense the gas blend and make the co2 condense so that it can be then sent to the evap.

Could be wrong, but the second option sounds like what you're planning.

Don't know if it will work well or not with a small compressor but the temps would certainly be good, even if capacity was a struggle.

Since we're speculating and all that ;)

Gray

[Nyx]

Funny i thought he says no autocascading. But when he says that he is using 2 different refrigerant with so much difference in condensing temp,
really keeps me thinking what could he do with it.
And Gray Both methods you mention are almost similar to autocascading and he says it is not.
Hmmm It really is a hard nut to crack :D

[SoddemFX]

Two stage compression with a small SLHX from the evaporator running in bettween the two compressors to take out some superheat from the first...?

Im just guessing, i havent got a clue realy :D

Tom

[\Karting_freak]

guys what is SLHX?!

[the_new_guy]

Suction line Heat exchanger, a heat exchanger on the suction line.

used is cascades, along with main HX

[Gray Mole]

Funny i thought he says no autocascading. But when he says that he is using 2 different refrigerant with so much difference in condensing temp,
really keeps me thinking what could he do with it.
And Gray Both methods you mention are almost similar to autocascading and he says it is not.
Hmmm It really is a hard nut to crack :D

Well strictly speaking to 'autocascade' you need to be separating your gasses in a phase separator and have 2 refrigerant loops.

However the idea is similar yes, that's the nature of 'blending' unless you have a perfect mix, you have differences in location of condensing based on temperature and pressure.

Finding an effective way to make a cascade gas condense well in a single stage is not easy, but those 2 I listed seem as if they should help a little.

I'm looking forward to when he get's it put together though, as I'd like to see more insight into how well the blending works.

Gray

[Tonic]

I guess it has something to lack of condenser.. maybe you want to use watercooling to condense refrigerant in heat exchanger?

[\Karting_freak]

so... when using SLHX you first cool the refregerant then is goes to compressor and then to HX, right? but wont ref condense in suction line?

[_HL4E_HalfLife_]

UPDATE!!

Here's a few more pics of the finished system and its not working like i hoped because i think i need a larger compressor so im gonna remove the 1/4hp 2600btu and put in a 1/2hp 6000btu Rotary.

If i get this thing working the way i want it its going to be a benching system.

Also later on im going to add a 2nd small compressor after the condensor & desuperheater to further increase the capacity and evap temp's during heavy benching.

[yngndrw]

Uhh I can't really follow them pics mate, can we have a diagram please ?

[Tonic]

Uhh I can't really follow them pics mate, can we have a diagram please ?

No really need for diagram, according to photos, this unit looks so classic. Just a untypical piping layout.

HL4E, have you got TXV/orifice for that such small heat load? You should place TXV bulb closer to evap outlet, since with that far location metering device might feed a lot of liquid, that may pass through suction pipe and absorb heat from environment, making heat capacity lower.

[_HL4E_HalfLife_]

No really need for diagram, according to photos, this unit looks so classic. Just a untypical piping layout.

HL4E, have you got TXV/orifice for that such small heat load? You should place TXV bulb closer to evap outlet, since with that far location metering device might feed a lot of liquid, that may pass through suction pipe and absorb heat from environment, making heat capacity lower.

Are you sure about that Tonic?

As for the TXV,yes i do have the right orifice (00-1/4hp) for this system and i put the bulb in that place because thats where i want it to measure the heatload at the moment.

Im gonna insulate it when i get it working right so it won't absorb heat from the environment.

[Tonic]

Are you sure about that Tonic?


Hey, that's something what I readed from my refrigeration book :)

When suction line warms up, bulb also warms up and because of that, pressure inside bulb increases. It causes opening orifice's striker more widely, so more liquid is entering to evaporator. When liquid boils off, temperature and pressure drops and those changes are catched by bulb, which starts to close a bit striker. Thank to that, TXV holds temperature, even if there temperatures changes.

See, a lot of TXV's notes say that you have to place bulb at evaporator outlet, because theoretically a last droplets of refrigerant have to boil off there where is end of evaporator. When you place bulb sooo away, a TXV is "cheated", because thinks that part of suction, which is placed between real evaporator and bulb locations is a evaporator :D So it doesn't really work as it's needed :)

That's how works in simplification. Remember that, there are other variables, like as superheat and pressure drops in evaporator :)

[_HL4E_HalfLife_]

Hey, that's something what I readed from my refrigeration book :)

When suction line warms up, bulb also warms up and because of that, pressure inside bulb increases. It causes opening orifice's striker more widely, so more liquid is entering to evaporator. When liquid boils off, temperature and pressure drops and those changes are catched by bulb, which starts to close a bit striker. Thank to that, TXV holds temperature, even if there temperatures changes.

See, a lot of TXV's notes say that you have to place bulb at evaporator outlet, because theoretically a last droplets of refrigerant have to boil off there where is end of evaporator. When you place bulb sooo away, a TXV is "cheated", because thinks that part of suction, which is placed between real evaporator and bulb locations is a evaporator :D So it doesn't really work as it's needed :)

That's how works in simplification. Remember that, there are other variables, like as superheat and pressure drops in evaporator :)


You misunderstood me Tonic. When i said "Are you sure about that Tonic?" i was refering to what you said when you said "No really need for diagram, according to photos, this unit looks so classic. Just a untypical piping layout."

[_HL4E_HalfLife_]

Well today i switched compressors to the 6000btu Rotary and i added a much better desuperheater and this time the system worked. With the other smaller compressor the cpu evap went up in temp, I turned it off when it got up to 36.7c. Now with the Rotary it went down to -17.8c. The temp right off the TXV was -36.7c.

Has anyone figured out what im doing yet? lol

[Bergo]

I'm still trying to figure out how this is "kind of like a cascade". To the best of my understanding you have a conventional single stage phase change unit with an unconventional layout (it's in a book case or something?) and you're using a thermal expansion valve instead of captube? and it looks like you have 1/4" copper pipe going in and out of your evap.
maybe I missed something?

[wdrzal]

how would you cool a cpu with that ? looks like a tvx feeds a lenght of copper tube (evaperator). Where do the frosted tubes that go upward out of the photo go????

[Nyx]

not sure if i got this right
compressor - desuperheater (Dont see it but i guess it's there) - condensor - filter - txv - evap

But condensor outlet goes to a slhx before going to filter to the TXV.

[_HL4E_HalfLife_]

I'm still trying to figure out how this is "kind of like a cascade". To the best of my understanding you have a conventional single stage phase change unit with an unconventional layout (it's in a book case or something?) and you're using a thermal expansion valve instead of captube? and it looks like you have 1/4" copper pipe going in and out of your evap.
maybe I missed something?

Im using the night stand because theres no other good peices of wood lying around and this stand is not a bad idea its compact,mobo goes on to and benching begins.:p:

Ps. you are still missing something! lol, heres a clue "condensor"

[Nyx]

Now who is right who is wrong .....Tell us :D

U mean the SLHX is condensing any second stage gas before going to the TXV.Is that what u are trying to do.

[Bergo]

in the first set of pics all you had a was a desuperheater coil and you said it didn't work, afterwards, in the latest set of pics you have a condenser with two 80mm fans and you say it's working now. no matter what the system, you're ging to need some way of transfering heat from the refrigerant to the air around it, even in a cascade/autocascade/ etc.

correct me if i"m wrong, but the heat has to go somewhere

[cdelong]

how loud is that thing??

[s7e9h3n]

I think this is a trick question. The real reason for this thread is because _HL4E_HalfLife_ thinks he's figured out a way to use his household vacuum as a vacuum pump..lol :p:

http://www.xtremesystems.org/forums/attachment.php?attachmentid=43090&d=1139200802

[_HL4E_HalfLife_]

in the first set of pics all you had a was a desuperheater coil and you said it didn't work, afterwards, in the latest set of pics you have a condenser with two 80mm fans and you say it's working now. no matter what the system, you're ging to need some way of transfering heat from the refrigerant to the air around it, even in a cascade/autocascade/ etc.

correct me if i"m wrong, but the heat has to go somewhere

The coil with the 2 80mm fans on it IS the desuperheater and the HX is the condensor. I hope that helps a bit.

[_HL4E_HalfLife_]

how loud is that thing??

its quite quiet really the only noise you hear is the compressor itself.

[Bergo]

without a condenser (you said what I thoguth was a condenser is actually a de-superheater) you don't have a device to turn your first stage refrigerant into a liquid, unless your pressure gets high enough to condense it at a high temp, even then, would that not be a horribly innefficient and ineffective design? maybe you should draw us a diagram, i"ve tried going over it in my head and can't make that setup work in the way I "think" you're meaning to.

[_HL4E_HalfLife_]

Bergo - Remember im only using 290 with running pressures of 7/150psi. If i didn't have a way to condense the refrigerant into a liquid than how do you explain all the frost you see in the pics?


Heres the diagram.

[Nyx]

:D i was a little correct. But how much could you subcool the liquid line to condense a low stage gas. I think you could add a SLHX like small a coil in coil to the liquid line to further improve subcooling.Maybe it may fully condense the CO2.

Hope you could add a the CO2 to it and tell us what you get.

[wdrzal]

you have a condensor,not a desuperheator.

[_HL4E_HalfLife_]

you have a condensor,not a desuperheator.

I have both the coil with the fans on it is the desuperheater.

[Icy]

http://www.xtremesystems.org/forums/attachment.php?attachmentid=43089&d=1139200802

looks like a condenser to me but maby im missing something. heh but it looks mad tho i look forward to seeing your final temps

[_HL4E_HalfLife_]

For those of you that haven't figured it out yet im using the the HX to cool the discharge the same way a 2nd compressor in a cascade would be used to subcool the discharge from the first stage. This larger compressor is able to handle the heatload from compression and any heat thats picked up from the surrounding air.

On startup the pressures are quite high 30/200psi but as the desuperheater starts to remove some of that heat and the HX gets colder the pressures start to drop and after 10min of running there at 7/150psi. That will drop even further once i insulate the lines.

[yngndrw]

Hmm, maybe you could try a large suction line accumulator to hold the volume of second stage gas at startup ? (One of them ones connected with a cap tube, not quite sure what they are called. I'm probably totally wrong though. :P)

Will be interesting to see what kind of load it can hold. :)

[runmc]

Is the vacuum cleaner part of the puzzle??:hm: :hm: :shrug: :shrug:

[jinu117]

Well.
1) What is the temp... does it hold load?
2) Do you think the experiment was success yourself?
Anyone whose been building units can make nice little experiments like this (I still think it's basically autocascade from different view). Only problem I've seen was... I haven't seen anyone successfully holding good load temp in reasonable manner. Ok... maybe there is no phase separation... but still...

[_HL4E_HalfLife_]

Well.
1) What is the temp... does it hold load?
2) Do you think the experiment was success yourself?
Anyone whose been building units can make nice little experiments like this (I still think it's basically autocascade from different view). Only problem I've seen was... I haven't seen anyone successfully holding good load temp in reasonable manner. Ok... maybe there is no phase separation... but still...

Im still tweaking the system a bit so i can't really answer ur 1st question yet.
The answer to ur 2nd question is yes it was, I wanted to see if a compressor can chill its own discharge and still be able to chill a cpu evap. I had -17c on the cpu evap yesterday and i hope to improve on that.

[Jack]

Bergo - Remember im only using 290 with running pressures of 7/150psi. If i didn't have a way to condense the refrigerant into a liquid than how do you explain all the frost you see in the pics?


Heres the diagram.
Well, it looks like a regular SS to me ;)
The desuperheater will act as a condensor and your HX is subcooling your liquid line...

[Jort]

Im still tweaking the system a bit so i can't really answer ur 1st question yet.
The answer to ur 2nd question is yes it was, I wanted to see if a compressor can chill its own discharge and still be able to chill a cpu evap. I had -17c on the cpu evap yesterday and i hope to improve on that.


from a point you won't able to hold the load from the condensor + compressor.
it will work but you won't have low temps i think.

quite worthless project in my view, just a condensor with a fan and a smaller compressor would do the same:)

just a singlestage with a slhx is mutch better performance wise:)

[_HL4E_HalfLife_]

Once im done with this project im gonna repipe it and add a 2nd small compressor to the HX to add capacity and further lower the cpu evap it will still have an air cooled condensor.

[kayl]

i see ya having some fun with the SLHX there _HL4E_HalfLife_
once its loaded things change alot , low sidfe pressure will rise and ya will find that the co2 isnt condensing quick enough.
cant wait to see it benching.
what sort of temps ya seeing there?? noload.

you really need a flexable suction line to reduce vibration on the cpu

[_HL4E_HalfLife_]

i see ya having some fun with the SLHX there _HL4E_HalfLife_
once its loaded things change alot , low sidfe pressure will rise and ya will find that the co2 isnt condensing quick enough.
cant wait to see it benching.
what sort of temps ya seeing there?? noload.

you really need a flexable suction line to reduce vibration on the cpu

I had -17.6c on the cpu evap and -36c right off the TXV.

It was fun while it lasted but i've scraped the project and am redoing it as a benching system.

[Carlz0r]

I have both the coil with the fans on it is the desuperheater.
You can call it a desuperheater, but without any other condensor, it's pretty much just a horribly inefficient condensor. Now, add another one, then you'll have a desuperheater :P

[johann]

I still dont see what was supposed to happen here. as far as I see you have a normal single stage with a condensor and a slhx.

I dont see why you call the condensor a desuperheater and the slhx a condensor. Why not build a normal singlestage without C02? With pure propane surely you will see double the temps. If -19c is the best tunloaded temp you saw, I dont think it will have the capacity to cool any cpu.

I dont see why c02 should come into the equasion?

[SlackeR]

I still dont see what was supposed to happen here. as far as I see you have a normal single stage with a condensor and a slhx.

I dont see why you call the condensor a desuperheater and the slhx a condensor. Why not build a normal singlestage without C02? With pure propane surely you will see double the temps. If -19c is the best tunloaded temp you saw, I dont think it will have the capacity to cool any cpu.

I dont see why c02 should come into the equasion?


The small coil condeses a gas that is easy to condense. This gas evaporates in the HX an condenses another gas, which goes to the evap. I think. They are not separated, but he shows that it can happen this way.
I think it is inefficient too ;)

[kayl]

I still dont see what was supposed to happen here. as far as I see you have a normal single stage with a condensor and a slhx.
I dont see why you call the condensor a desuperheater and the slhx a condensor. Why not build a normal singlestage without C02? With pure propane surely you will see double the temps. If -19c is the best tunloaded temp you saw, I dont think it will have the capacity to cool any cpu.
I dont see why c02 should come into the equasion?


A while back a few guys successfully got a hint of c02 to condense in normal single stages to give nice noload temps at 0psig.:toast:
Some went that bit further with a SLHX and again got some nice noload temps at around 0-20psig again. I guess he was hoping to try his luck and see if he could get some nice loaded temps, I know I couldn’t rest until I tried my ideas, build the same old single stage over and over does become boring, got to think outside the circle every now and again.:stick:

[_HL4E_HalfLife_]

Im not sure where you guys are getting the idea that i added Co2 to the system?? I did say that i "might" add some Co2 if all goes well....

Anyhow.. I've just spent the last 5 hours or so rebuilding this basically into a new system. I taken out the TXV and put in 3.5m of .031 cap tube and added the 2nd compressor for those beefy prescotts lol. Now this system will be able to condense Co2 in the cap tube even without the help of the 2nd compressor. I got the main system running today and from the time i turn it on to -50c is about 6 seconds :eek:, Unfortunitly my UEI probe broke and was sent back to be replaced under warranty and i got a new one and just found out its defective:upset: :down: so im sending this one back.

What probe do you guys use for ur UEI Thermometer? like i mean the stock one is an ATT19 which is what i've been using but its not very robust so what one do you guys prefer is the best for surface temp readings?

[_HL4E_HalfLife_]

COMON PEOPLE!! What UEI Probes are you using???:confused:

[s7e9h3n]

COMON PEOPLE!! What UEI Probes are you using???:confused:
Type-K? :confused: :p:

[Hell-Fire]

Type-K? :confused: :p:

:thumbsup: UEI Probage (http://www.ueitest.com/productList-probesthermocouples.html)

I would have thought someone in the -100C Club would know this. Man, I love rib shots....woohoo. Bet that left a mark. :devil:

[_HL4E_HalfLife_]

:thumbsup: UEI Probage (http://www.ueitest.com/productList-probesthermocouples.html)

I would have thought someone in the -100C Club would know this. Man, I love rib shots....woohoo. Bet that left a mark. :devil:

How should i know that everyone else is using a k type probe???? theres like 7 or 8 different probes that work in the UEI DT150 and DT200 Thermometer. The standard probe that comes with it is a J type oven probe (ATT19) thats what i've been using.

[jinu117]

Wierd... my DT200 comes with 2 K-type. In fact, all 4 i have gotten came with same probe.

[_HL4E_HalfLife_]

Wierd... my DT200 comes with 2 K-type. In fact, all 4 i have gotten came with same probe.

Can u get the probe model number? i wanna look it up and see whats the difference.

[Comp-Freak]

My DT200 came also with k-type. It has the following text on it:
K
Chromel +
Alumel -

No other numbers.

[johann]

mine also comes with type k probes the same as Comp-Freak

[_HL4E_HalfLife_]

My DT200 came also with k-type. It has the following text on it:
K
Chromel +
Alumel -

No other numbers.

The probe model should be on the plastic case. (look at pic)

[s7e9h3n]

The probe model should be on the plastic case. (look at pic)
Now that I think about it, that's the one which came with my DT150 as well, but my DT200's came with Type-K probes......

[Comp-Freak]

The probe model should be on the plastic case. (look at pic)My case doesn't states the probe type. The manual states only "Two type K thermocouple probes".

[Edit] pic