What would it take to build a cryogenic cooler?

[Naja002]

Now you're an RC pilot....

Last night I went to bed thinking about this issue from another point of view. What's required for a turboexpander to work in a situation like this is predominantly it's size. I had initially investigated the use of small turbochargers for motorcycles having a displacement of 500cc. But I quickly realized the amount of flow through them would simply be too great for any system of this size. So then I thought about my old hobby, radio controlled aircraft. It dawned on me that if turbochargers existed for them, they would be properly suited for this project. So now I submit to all of you the following:
1.) RC turbo charger

2.)
3.) How to Make Turbochargers for Nitro Powered RC Cars

Did you bother to read that thread, Shingoshi? The tubocharger does not work for their application--or as it's claimed. The thread is full of:

Post #9--This is the biggest load of bull I have ever heard... You can't put forced induction on our nitro engines. It is impossible. This is because the exhaust port closes after the intake ports. If you look at the sleeve, you will see that the top of the exhaust port is higher than any other intake ports. Therefore when the piston is reaching the top of the stroke, pressure gained, if any at all, by your so called "turbocharger" would be forced out of the exhaust port. Therefore forced induction does not work on our nitro engines, not even the slightest amount.

Also, by having all of this blowby, you are not only waisting tons of fuel, but you are also eliminating the natural forced induction created by a tuned pipe. A tuned pipe creates backpressure. This is when the exhaust gases reach the end of the pipe and reverberate back to the engine. When an engine is running, some of the fresh air and fuel mixture is expelled out of the exhaust port. What the backpressure does however, is push this air and fuel back into the combustion chamber. Since all of the other ports excluding the exhaust are closed, this creates a natural forced induction. Have you ever wondered why our nitro engines run with much more torque and horsepower with tuned pipes instead of open pipes? This is also why tuned pipes can also be considered "low end" or "high end" pipes. This is mostly due to the shape and length of the pipe which causes the backpressure to be most efficient at different RPM ranges.

And since your "turbocharger" doesn't work and merely heats up your engine, I bet you will go much faster by sticking a nice tuned pipe on it and going back to air cooled.

Fools will always have foolish notions...

Post #26--The RBInnovations supercharger does not in fact "supercharge" RC engines. The extra air that is forced in through the carb merely blows out through the exhuast port as killer89 mentioned before. Therefore when the air and fuel is forced out of the exhaust, you are merely leaning the engine by taking away the fuel and replacing it with air. Therefore, instead of paying $180 for a heap of metal, you can just lean out your engine. Also you have to realize the supercharger is draining HP and torque from the engine by giving extra load to the engine to spin the vanes.

There's nothing positive in that thread.....

Now that we've seen what one would look like, those of you who have the means (metal working materials) should now focus on how to produce one, instead of the constant rants about why this is impossible or implausible. Simply put, start being productive contributors to a working solution, instead of only wanting to detract from one.

Shingoshi

Once again, that's your job. You've not given anybody anything here, except words. Prove your own theories... Buy, build or contract your turboexpander. Here's one that should fit your budget: Turboexpander




Might also want to take the time to read the comments on your "How to make a turbocharger" link.

on 6/20/2007 Where the hell in this article does it tell you how to make a turbocharger for your RC nitro car????????? I am learning disabled and can't read....... or the author needs to let everyone know how to actually MAKE A TURBO, if he/she does not know how to do this, why in gods name are they allowed on a computer as they will surely gum up the keyboard with drool???

How to MAKE Turbochargers:

Things You'll Need:

* RC supercharger
* Nitrous injection mechanism
* Charger heads
* Flywheels of the appropriate size
* Zip ties
* RC fuel line
* RC fuel cell
* Threadlocks

More smoke and mirrors....

[Gautam]

Let me be more explicit. Stay out of this thread Naja.

[runmc]

In all fairness to Shingoshi , I am going to leave this thread open for now. If the contents bother you, please stay away from the thread. Shingoshi is entitled to express his dream .

No more flaming

[Shingoshi]

In all fairness to Shingoshi , I am going to leave this thread open for now. If the contents bother you, please stay away from the thread. Shingoshi is intitled to his dream even if most of us consider it spam.

No more flaming

I will attempt to give thorough information to justify my ambitions and claims here.

The first thing that needs to be pointed out, is that turbochargers do in fact work. There is no debate about that. The problem that exists with using them on nitro-fueled engines, is that those engines are predominantly two-stroke engines. Two-stroke engines simply cannot provide the exhaust pressure for turbochargers to function properly. YOU NEED A FOUR-STROKE ENGINE'S EXHAUST PRESSURE FOR THE OPERATION OF A TURBOCHARGER! I knew that before examining this subject. The point here is that it IS POSSIBLE to build turboexpanders small enough to meet the needs of a compressor, since the compressor IS providing the pressure required to drive a turbocharger. Additionally, the vortex tube's pressure and heat is what we're counting on here.

I will now go back and provide the edited comments to my last post to explain how this should work.

Shingoshi

[runmc]

We need no explanation on whether your theory will work or not. If you want to post a project get on with it. No more theory or explanations please.
If you don't get on with the project, the thread will be closed.

[teyber]

an old saying goes:

when the horse is out of the stable, its time to get some hay.

Not sure what it means but its possible it applies here.

[Shingoshi]

We need no explanation on whether your theory will work or not. If you want to post a project get on with it. No more theory or explanations please.
If you don't get on with the project, the thread will be closed.

It will take a while to gather some of the components. Unfortunately, some things cannot be constructed unless other parts are available. If I am in the process of gathering components, but can't always assemble them, am I to be constantly accused of not doing anything? I initially started this thread to simply ask a question. It was only after I started giving some answers as to why I believed this is possible, that I started getting a lot of criticism. In the process, I was trying to point out that some of the criticism was unjustified.

I didn't open this thread looking for or expecting to start arguments. I was simply wanting to know what had anyone done to attempt getting near-cryogenic temperatures for a 24/7 system. Ironically I find myself cornered into a position I might have otherwise not taken.

However, as of this weekend I've decided to focus on building the external heat dump, since this is the most critical component discussed so far. This one feature will be necessary no matter what direction I chose ultimately.

I'm sorry that showing that I've already started accumulating the components for this system isn't enough for some. But as someone here already derisively pointed out, I don't have the budget to acquire a large number of components at a time. You should simply know that I don't spend money on anything that I'm not committed to doing. I don't know what more to say than that.

Shingoshi

[Shingoshi]

How to put compressors in parallel
Parallel compressors single condenser

Parallel Compressors System:
With a (parallel) rack system, the multiple compressors can stage on, off or unloaded
in cost-saving increments to match the ever-changing cooling requirements.

Variable capacity multiple compressor refrigeration system
EnergyEfficiency

Shingoshi

[Postal Dude]

Hey dude.

With regards to your parallel compressor plan, noone has disputed its use for energy efficiency, it can and has been used to great success. What EvoCarlos pointed out was... You said that if one compressor failed then the system could carry on running with reduced efficiency. If you did run your unit in this state, various nasty gack from the burnt out compressor would be pumped through your system, potentially clogging a cap tube or other metering device, which could lead to a dangerous situation pressure wise.

I really and truley hope you build this and that it works well for you as it would open up new avenues for cooling. If it doesnt work, at least you'll have learnt alot in the process.

[Shingoshi]

Hey dude.

With regards to your parallel compressor plan, noone has disputed its use for energy efficiency, it can and has been used to great success. What EvoCarlos pointed out was... You said that if one compressor failed then the system could carry on running with reduced efficiency. If you did run your unit in this state, various nasty gack from the burnt out compressor would be pumped through your system, potentially clogging a cap tube or other metering device, which could lead to a dangerous situation pressure wise.

I really and truley hope you build this and that it works well for you as it would open up new avenues for cooling. If it doesnt work, at least you'll have learnt alot in the process.

It's just that in reading on this issue elsewhere on this site, no one mentioned it. True, I may have missed it. After all, I haven't read every post on this entire forum. But let's just hope one of the compressors doesn't go down like you said. Because that would be a very bad situation, unless they could somehow be isolated from contaminating the other units.

Should I be more concerned by the fact that I'm using discontinued compressors. The Rechi's are brand new. And so are the Danfoss. However, the Danfoss are warehouse mishaps. Supposedly, they fell off the shelf on which they were resting. So it really comes down to just how durable do compressors tend to be.

And I know that I have likely looked very fickle through all of this. But there are simply too many things to consider and think I have the final answer. With that in mind, I'm thinking of creating two separate coolant loops divided between the Rechi (R-22) and Danfoss (R-404a/507) compressors. The reason is that I'm concerned that there won't be anyway to deal with the dissimilar lubricants required by each group. So I'm thinking of using one group for the external condenser, and the second group for the internal heat management. The only unit these two groups would share in common would be the M60 heat-exchanger I already have. From what I've read, it seems that I can use R-600a in the Rechi without any trouble. But then again, I may have missed something again. If that's not a problem, it comes down to whether the four of them could handle the load being dropped on them from the internal system requirements. I don't know.

It seems that being able to cool the R-404a lower than what it could get from simple air cooling would be a great benefit. Since the system would start out with less load on it. But once again, that's conjecture.

Thanks for pointing that out...
Shingoshi

EDIT: Look closely! This should give you a clue just how DIFFERENT I tend to be.
[IMG=http://img295.imageshack.us/img295/9323/doesthisgiveyouaclue.th.png]

[tiborrr]

Different maybe, but that does not automatically mean you are competent. Just a thought.

[teyber]

Hey dude.

With regards to your parallel compressor plan, noone has disputed its use for energy efficiency, it can and has been used to great success. What EvoCarlos pointed out was... You said that if one compressor failed then the system could carry on running with reduced efficiency. If you did run your unit in this state, various nasty gack from the burnt out compressor would be pumped through your system, potentially clogging a cap tube or other metering device, which could lead to a dangerous situation pressure wise.

I really and truley hope you build this and that it works well for you as it would open up new avenues for cooling. If it doesnt work, at least you'll have learnt alot in the process.

yeah man if a hermetic compressor burns out it will destroy ever component in the system. with 4 compressors or w/e you are 4 times as likely to have that happen.

What about instead of using those rechi's you use those huge 1hp copeland compressors that are used in commercial cascades?

[Shingoshi]

yeah man if a hermetic compressor burns out it will destroy ever component in the system. with 4 compressors or w/e you are 4 times as likely to have that happen.

What about instead of using those rechi's you use those huge 1hp copeland compressors that are used in commercial cascades?

I've seen them for sale on Ebay. And they are powerful indeed. The problem is the voltage. I live in an apartment, and I don't think the management would rewire my unit for a new 230V line.

That's why I've been concentrating my efforts on what I can achieve with 115v instead. For people who live in Europe, 230v isn't a problem. But here in the States, you don't typically see that high voltage unless you're in an industrial zone. I've thought about attempting to run 230v. But that would require that I use the line from my oven to power this system. There are logistical issues with doing that. The least of which would be creating ~30' power cord with a locking lead into the computer case. I had been thinking the refrigerator had 230v. But it seems it runs on standard household current. So I don't know about the viability of the higher current.

But I did think about it...
Shingoshi

EDIT: I'm going to search Google and see if Copeland even makes a 115v compressor. If they do, then maybe I can find one, once I know the part numbers to look for.

EDIT: Ok. Here's a list of the Copeland 115v compressors that I've found. I'll list this in order from the largest to the smallest.
1.) KAAB-007E-CAA-800
2.) KAMB-007E-CAA-800
3.) KAGB-005E-IAA-800
4.) KAMB-007A-CAA-800
5.) KAAB-007A-IAA-800
6.) KAGB-005A-IAA-800
7.) KANB-005A-IAA-800

Clicking on any one of those links, will take you to the page where I got the data. You can see the refrigerants each model uses. If you want, tell me which refrigerant makes the most sense. The largest one of these uses R-404, which is the same as the Danfoss SC18CLX.2. I don't know how much larger that model is than the Danfoss. Because the Danfoss is pretty large itself, having a displacement of almost 18cc.

[ultralo1]

Copelend RF41C1E-CAA-929, 115V

[Shingoshi]

Copelend RF41C1E-CAA-929, 115V

Where did you find that one? I mean I could look. I'm going to look for it now! But if that's available on Ebay, that would be especially nice!

EDIT: I just looked. And Google turns up a blank page with nothing found. Are you sure you have the correct model number? On further examination, the Copeland I listed above as the largest 115v compressor, is simply too heavy for this application. It definitely seems to have a cast-iron frame. That may be expected for industrial applications. But for this one, it's not appropriate.

Shingoshi

[ultralo1]

Are you sure you have the correct model number?

Yep. Shipping wieght 45LBS

[[XC] gomeler]

What's the weight on the 4 rechis? I've got one of Copelands largest 110v reciprocating compressors sitting at my feet. Model number RS97C1E-CAA 1.5hp 115v-1ph 9590btu/h with a 20f evap and 120f condenser while pulling 1940 watts all in a 54lb package. Compare that to 4 rechis or 2 SC18s and I think the Copeland would be more compact and lighter. The only problem is the startup current.. going to need a 30 amp circuit to keep from tripping the breakers.

[Shingoshi]

What's the weight on the 4 rechis? I've got one of Copelands largest 110v reciprocating compressors sitting at my feet. Model number RS97C1E-CAA 1.5hp 115v-1ph 9590btu/h with a 20f evap and 120f condenser while pulling 1940 watts all in a 54lb package. Compare that to 4 rechis or 2 SC18s and I think the Copeland would be more compact and lighter. The only problem is the startup current.. going to need a 30 amp circuit to keep from tripping the breakers.

I had already determined that I shouldn't proceed with anything until I have the voltage issue worked out. Because even with the multiple units I currently (no pun) intended to use, amperage will still be an issue. So I really have to work on the current (again no pun) issue before I do anything else.

EDIT: This is definitely funny. In searching Google, I found one of the few links for that compressor to be one of yours. Odd Compressor Spec Question
I'll have to read it now and see what you had to say there.

EDIT: MAN!! How did you get lucky enough to come by that compressor? I see it listed for $2,400. Damn lucky indeed!

Shingoshi
EDIT: I just want to say thanks guys!

[[XC] gomeler]

The wonders of ebay I can't wait to use it someday, I've had it for roughly 18 months just waiting for the perfect project to use this baby. I bet it won't even start when I finally do use it

[SoddemFX]

The first thing that needs to be pointed out, is that turbochargers do in fact work. There is no debate about that. The problem that exists with using them on nitro-fueled engines, is that those engines are predominantly two-stroke engines. Two-stroke engines simply cannot provide the exhaust pressure for turbochargers to function properly. YOU NEED A FOUR-STROKE ENGINE'S EXHAUST PRESSURE FOR THE OPERATION OF A TURBOCHARGER! I knew that before examining this subject.

http://people.bath.ac.uk/ccsshb/12cyl/

Regardless, it doesn’t matter because the whole quoted paragraph was drivel.

The point here is that it IS POSSIBLE to build turboexpanders small enough to meet the needs of a compressor, since the compressor IS providing the pressure required to drive a turbocharger.

This sentence does not make sense. I think I understand what you are trying to say but I doubt that a normal refrigeration compressor will be able to provide enough flow rate and pressure to even spin an automotive turbine, let alone drive an effective cycle where work can be done in the turbine.

If you want, tell me which refrigerant makes the most sense.

How can anyone tell you which refrigerant makes the most sense when you haven’t listed any requirements. For the benifit of people who want to help you, it might be worthwhile to state these requirements.

This is because I have spent one hour of my life reading this thread and I have no idea what you are actually trying to do. The sad thing is that I will never get this hour back, it is gone forever…

Tom

[Shingoshi]

The wonders of ebay I can't wait to use it someday, I've had it for roughly 18 months just waiting for the perfect project to use this baby. I bet it won't even start when I finally do use it

That's always been my biggest fear about doing business on Ebay. But after reading about the Danfoss compressors on this site, finding them out of stock at the time, I found and purchased the Rechi compressors instead.

Now, back to the "current issue" , I found this for Danfoss. But again, it's 230v. Crap, I should live someplace else where I can do the things I need to without voltage problems. Do you guys have any ideas of how to get around this perplexity?

Shingoshi

[Shingoshi]

http://people.bath.ac.uk/ccsshb/12cyl/

Regardless, it doesn’t matter because the whole quoted paragraph was drivel.

This sentence does not make sense. I think I understand what you are trying to say but I doubt that a normal refrigeration compressor will be able to provide enough flow rate and pressure to even spin an automotive turbine, let alone drive an effective cycle where work can be done in the turbine.

How can anyone tell you which refrigerant makes the most sense when you haven’t listed any requirements. For the benifit of people who want to help you, it might be worthwhile to state these requirements.

This is because I have spent one hour of my life reading this thread and I have no idea what you are actually trying to do. The sad thing is that I will never get this hour back, it is gone forever…

Tom

The turboexpanders were only intended as a means to rechill the refrigerants leaving the vortex tubes. That was the only intended purpose for them. I have since moved on to other considerations. So I hope it doesn't distract you any further. Because I'm no longer thinking about it.

Vortex tubes on the other hand have the ability to drop a refrigerant's temperature without the typical need to expand other higher-temperature refrigerants in order to condense lower temperature refrigerants. That's the point you've missed. I'm sorry. I should have summed it up before so that some could get it. The idea is to have all of your condensed refrigerants in a single mixture (solution), so that when the evaporation process begins it will be continuous along an evaporation path until all refrigerants have evaporated. What is expected is, that the lower temperatures forced into the first-stage vortex tube (by using the evaporation process (path) to cool the upstream refrigerants), the lower the resulting temperatures from the vortex tubes will be. It produces a loop where the refrigerants going into the vortex tubes continue to drop. They would continue to go lower until they reach a point of equilibrium, where they go no lower. The was something that was observed in detailed studies by researchers on this topic, and revealed in numerous patents that have come about.

As far as the heat load goes. The greatest load in the system will be to rechill the refrigerants escaping the vortex tube's hot outlet. Typically, that heat is @230F with a 70F inlet temperature. But here again, if I lower the inlet temperature going into the vortex tube (@0C) to begin with, the hot outlet gas from it will be considerably lowered, as will the cold outlet temperature. My eight processors will produce no more than 600W for 8x75W AMD Shanghai cpus. There will no other major heat sources to contend with. But, at the most, the system will have approximately 1000W capacity for safe operation. But then, for all the comments about cooling the compressors as well, they must be considered also. For the purpose of cooling the case's interior, I'm thinking about using a plate evaporator, like the ones used for marine cooling boxes.

Shingoshi

EDIT: On the other hand, maybe the TURBOEXPANDER issue shouldn't be dead after all. I don't think I need to say anything other than this. And if it's not enough, that's your problem.

Microturbomachinery Patent

[Shingoshi]

Claude Cycle

The Claude cycle is a widely used cooling process in refrigeration technology. It combines isenthalpic and isentropic expansion. A refrigerator based on the Claude cycle comprises a compressor at ambient temperature, a series of heat exchangers, an expansion turbine and a Joule-Thomson valve. The principle used is to expand a part flow of the process gas in the turbine and therewith cool it down ( isentropic expansion). The turbine part flow is then used to precool the main gas stream by the means of the heat exchangers. The precooled main gas stream is further cooled down by isenthalpic expansion via the Joule-Thomson valve.

Of course, that probably sums it up too much for you!

EDIT: In this case, the Joule-Thomson valve is replaced by the vortex tube.

Shingoshi

[[XC] gomeler]

Curious, do you plan on building your own vortex tubes or is there a factory shelf part within the sizing that you would need for your application?

[ultralo1]

As far as the heat load goes. The greatest load in the system will be to rechill the refrigerants escaping the vortex tube's hot outlet. Typically, that heat is @230F with a 70F inlet temperature.

How many BTUs/HR does this equal?
This is a needed value.

But here again, if I lower the inlet temperature going into the vortex tube (@0C) to begin with, the hot outlet gas from it will be considerably lowered, as will the cold outlet temperature.

How were you going to do this?

My eight processors will produce no more than 600W for 8x75W AMD Shanghai cpus

This will need to be added into the total heat load.

But then, for all the comments about cooling the compressors as well, they must be considered also.

Since the compressors will be enclosed within this case, all the heat load from the compressors will have to be transfered to the outside. To figure out how much wattage that is, take the voltage mutiplied by the RLA and add 10%.