chooseing a gas

[Nick_Black]

hello I'm New to Refrigerants, I understand the principles and all that, but never actually worked on a unit. but me bieng me, I want to dive right off the deep end :P

to hopefully bypass a lot of neg. feedback I'll jump straight to my main question:

what are some good gases to use that are

a: easy to get a hold of
b: non toxic
c: non flammable
d: ozone friendly (if possible)

originally I was thinking propane because it's easy to get a hold of, but it's got a nasty habit of going boom.

temps I'm shooting for -10 to -40 approx, I'm really not picky, heck I'd be happy with a 0*(C)

and as a side question, how much does water affect the system? I know most/all systems have a dryer filter, but how much would it affect the system?

Thank you in advance.
Cheers! Nick_B

[Brian_UK]

Water will kill a compressor. it will also freeze in any small orifice in the system.

How are you proposing to use this refrigerant?

[US Iceman]

0-40°C is quite a range of possible operating conditions. What you seem to be asking is for a refrigerant that fits all things. Sort of a like a shoe that will fit anyone.

Water in refrigerants is a no-no.

What are you truing to do? You state you have no experience, but understand the principles... Fresh out of school, heh?

Fill us in on what you want to do and why. Then we can assist with more defined information.

[Nick_Black]

sigh, I'm probably going 2 be made fun of for this, but oh well...

like I said, I'm going in from the deep end

I want to:

a: Build everything from the ground up ( includeing the compressor (which means, machine the pistons, crank, ect ect, and make it beable to run off a 12v computer power supply))

b: assemble everything

c: if I get successful, I want to hook it up to a water cooling rig for my computer

that's why I'm not too concerned about temp becouse my goal is to simply get it to work at first, I'll work on getting a proper temp after i know I can build a working unit.
(also why I want a safe gas so I don't end up killing myself)

you wouldn't happen to know where I could get a filter dryer would you?

p.s. I know I explained myself verry ametuerly, I'm not good at explaining myself, and incase your going 2 ask me how I'm going to machine everything, I'm first going 2 build a 5axis cnc (working on that now) and then use that for this project)


sigh.. sorry for typing so much, I've never been good at summing stuff up

cheers!

[Eeram]

Why do you want to re-invent everything that is already there, and working properly?

If you need to cool your overclocked computer, contact the appropriate people. I would believe that this forum is for much more serious refigeration issues!

[Nick_Black]

why? to learn that's why.

it's one thing to see pictures and read and learn theory. taking a unit apart is the next step. but building from the ground up you get to experience mistakes so you truly know why things are the way they are, and perhaps something that might be a mistake in one thing
ex. water freezing up inside the system
might help with inventing something that does not exist yet.

that's why. and computer is just the first part, if i know why/how/what ect, then i can apply that to other things

yes, my need might not be as great as others, and it's possible i posted this in the wrong section, bus is knowlede not valuble?

and I want to know of a safe gas so I can not only learn, but learn safley.

(and to thwart a question I foresee, I'm going into collage soon for robotics, and don't feel like taking another course for a mere hobby.)

[Brian_UK]

Eeram, I think that you miss the point. The man wants to make something with his own hands and sweat. He's not trying to reinvent the wheel he wants to experience building a wheel.

[Frikkie]

Hello nick black

Propane can work for fridge gas if you have no air in the pipes with it.
A computer power supply is not strong enough to make a piston type of compresser run but you can use a battery with a power supply to make it charge.

Why do you want to make your computer so cold as -40c. You can't use water to cool if it's below 0c degrees unless you pressureise it or add salt or antifreeze.

Sorry, I read your questions again but I think i still think i dont understand what you are trying to do.

[acnerd]

I'm first going 2 build a 5axis cnc (working on that now) and then use that for this project)

I'm keen to see the cnc machine that is going to machine the compressor!!

[Nick_Black]

I'm keen to see the cnc machine that is going to machine the compressor!!

I'll post a vid of it when I'm done (hopefully somewhere in the middle of August..) (and also HOPEFULLY how you can make your own cnc as well..)

and thank you Frikkie.

I was concerned about propane becouse it is flammable, and I wasn't too shure how safe it would be under pressure, i know it should technicly be safe in a vacuum, but since I'm building it myself i'm a bit nervous about leaks.

[Frikkie]

I don't think the pressure is a problem with propane. It can only go to a certain pressure before it condensates to a liquid if there is no air or other gasses in the system. We always try to stay over a vacume on the cold side of the machine when we use propane, if there is a leak somewhere in the pipes with a vacume it can suck in air an be a saftey problem with an expolsive mix. I have a problem like this already with my cold room which is almost in vacume. This is also why we only use lpg or propane for fridges that are running above freezing 0c inside the cabinet. We also put a big sticker on the machine so if someone else is working on it they can know it can be dangerous for welding pipes.

[acnerd]

We also put a big sticker on the machine so if someone else is working on it they can know it can be dangerous for welding pipes.

Not the old DANGER GEVAAR INGOZI stickers??

[Frikkie]

Not the old DANGER GEVAAR INGOZI stickers??

Ja, you must know the South African way. The stickers we have we cut out the boerboel picture and just use the writing with 'LPG' added at the end in kokie pen. The refrigeration suppliers in Piketberg don't stock ready made ones.

[Gary]

You might want to start here:

http://www.refrigeration-engineer.co...ad.php?t=19701

[Frikkie]

Hello again Nick Black,

I spoke to my friend about your question and we have two thoughts. Acnerd is right about you can't being able to make a piston compressor without a machine shop. So we think that a ammonia machine using absorption with no compresser can be made in your garage at home from old parts. You can run it with a small paraffin burner instead of electrical supply.

It will be too slow to use alone for making your computer cold but you can make a oil bath as a secondary coolant and place your computer inside with a agitation motor and use the ammonia unit to make the oil cold. I dont think you can make it 40 under freezing temperature but it should go to 0C or maybe less. I cannot give you a plan for building but I looked with Google and a there is internet information here. Also here. You will have to mount your CD parts outside of the oil bath and please read first about ammonia dangers before building and try to use an old computer first in the oil so problems don't cost too much.

I know ther will be many problems with this design and some will laugh but there are many experianced people here I think can help you make it work.

[Frikkie]

I see with google here that somebody already uses oil. They are more expert with computers and they use heat sinks for better moving of heat but I think the separate bath is maybe still better and less silicon maybe less leaks. They also use no refrigeration, simple can be better and less money for you.

[DocFreeze]

Dude, I applaud the moxie! Don't settle for what textbooks, or 'experts' tell you. If you can, try it yourself.

The parameters that you gave have obviously scrambled some jets here, but don't let it stifle the mission. It sounds like even if you have to install 2x 1,000W PSUs you may still want to try it... rock on!

Difficulties that you will encounter if you are making a miniature of a conventional system is operating pressure and your target temps. If you can't sacrifice your low temperature requirement, stay away from gases that go to vacuum at those temps like R-134a or you'll have moisture probs.
I'd also suggest you watch out for high discharge pressures, like R-410A, or you may have failures.

Last thing, when you say 'Ozone Friendly', are you actually concerned about evironmental issues, or are you more concerned about availability? Many of the non ODP refrigerants that companies like mine have been using to get away from R-22 have turned out to have very high GWP(R-404A).

[Nick_Black]

wow, i leave for a while and come back to find a ton of info! thanks guys XD XD

Gary: yes, i read that post before i evens started this one thanks though XD

Frikkie: I really like your ammonia Idea and i might go for it actually (and my dad has a shop that with some of my own tools should be able 2 do what is needed....)
plus, I wouldn't want you to spoon feed me how to make it anyways, that would take all the fun out of it ^.^

DocFreeze: thanks for the encouragement and also thanks a lot for the tips too! and I'm more concerned about availability then the environment, but the environment is a nice bonus (especially since i can foresee a lot of leeks in the early stages..)

[Gary]

Here's what I would suggest:

Purchase the smallest, cheapest window A/C you can find. Buy a Rubbermaid Slim Cooler. Take the window A/C apart and install the evaporator from the A/C in the cooler. This will be your chiller for your computer.

Now put it all back together, evacuate it and charge it with propane. It won't go boom unless it mixes with air and hits a flame. Be careful.

Fill the cooler with denatured alcohol and pump the chilled alcohol to your CPU water block.

If you can make this work, you will have learned a lot about how a refrigeration system works.

Then, since you want to build a system from the ground up, start replacing each component with your own homemade version of it.

Do the compressor last. That way we can forestall the point at which I say, "You are out of your friggin' mind."

[Gary]

Last I heard, R134a was still available in automotive parts stores in Canada. You may want to check on that. But you will need to change the compressor oil to polyolester (POE) oil.

[Shingoshi]

sigh, I'm probably going 2 be made fun of for this, but oh well...

like I said, I'm going in from the deep end

I want to:

a: Build everything from the ground up ( includeing the compressor (which means, machine the pistons, crank, ect ect, and make it beable to run off a 12v computer power supply))

b: assemble everything

c: if I get successful, I want to hook it up to a water cooling rig for my computer

that's why I'm not too concerned about temp becouse my goal is to simply get it to work at first, I'll work on getting a proper temp after i know I can build a working unit.
(also why I want a safe gas so I don't end up killing myself)

you wouldn't happen to know where I could get a filter dryer would you?

p.s. I know I explained myself verry ametuerly, I'm not good at explaining myself, and incase your going 2 ask me how I'm going to machine everything, I'm first going 2 build a 5axis cnc (working on that now) and then use that for this project)


sigh.. sorry for typing so much, I've never been good at summing stuff up

cheers!

Well, I for one am NOT laughing at you! But then again, we may both be equally insane. The system I want to build is also for a computer. However I want to do as little as needed to get this thing to run and perform properly.

I came here because I'm looking for a gas that I can use in the four identical compressors I just purchased. They were initially intended for R-22, but I too want to use R-290. The big thing here, is that I'm shooting for much lower temperatures. For that reason, I'm considering doing an autocascade. But most of all I want to know that the refrigerants I choose will actually work as expected without error or hazard.

Now I'll read what everyone has said here.
Shingoshi