My First Cascade "Fat Boy"

Ok Go easy first lads, me and my friend built this so far and it has all been done with learning from the Internet and a friend i met on line. who i chat to over the phone. One of the nicest chaps i met, or haven't met. Anyway...

1st Stage 1 and a 1/2 HP - 34cc "R404a"
2nd Stage 1HP - 24cc "R1150"

http://img413.imageshack.us/img413/4...ideviewaz1.jpg

http://img91.imageshack.us/img91/117...iersidess0.jpg

http://img261.imageshack.us/img261/4791/dscf0343id6.jpg

http://img291.imageshack.us/img291/103/dscf0338so4.jpg

http://img252.imageshack.us/img252/5569/dscf0354lc9.jpg

http://img388.imageshack.us/img388/1256/dscf0358zj3.jpg

Not complete yet. I have had 2nd stage under 350PSI for past week leak free :D. I have friend who is fully trained and helps with the charging and reclaim. And of course i will be careful with the Ethylene.

Should hold a Quad core CPU to around -100oC. :D

Nice work.

One comment to help with construction in the future..

The blue Alco brazed joints could be improved by using successively smaller pipes fitted inside each other to create a better looking 'reducer'.

It can also reduce the chances of filler getting inside the item.

3rd picture shows the bulb for the TEV un-insulated. I can't see it in the later pictures, but make sure you insulate it.

I am also glad to see that its not just me that snaps the suction stubs off them dam comps when trying to expand them...lol
Why the don't come in a bigger size is beyond me.

Glad to see you working to high standards and good luck with the rest of the project.

Chillin:) :)

Get rid of the schrader valves. Especially on the suction sides. You will probbably be running the suction in a vacuum.

What refrigerants are you going to use?

Install thermocouples (T type) on the in and out of each evap. This will help you charge it.

Very good :D
I think I see this over at pclincs, I would of posted there but fell out with the old dill that runs it.

Thanks for posting it here.

Many thanks for the input and tips guys. :D

Brian_UK
I knew the second i brazed the first joint on the oil sep that i should have used reducers. Had 1 leak from the entire build and it was a joint there. :( All sorted now :D

I'm going to add access valves for the High side on each stage to help with the vacuuming process.

chillin out
The bulb and HX is uninsulated at the moment as is the HX. I plan to finish the rest of the unit the coming weekend. so i am pretty excited.

Also adding a controller and sorting the electrcis also. My friend who's project it is as much as mine is doing the electrics. He has a great electrical background so its all pretty simple to him.

Anyway i am glad i posted here so you can all enjoy me and my friends work.

ultralo1 http://www.refrigeration-engineer.co...ser_online.gif
You say remove the acces valves on the low side? I plan to have schrader valves on the high side to help vacuum as i mentioned. So you mean have high side access but remove low side valves?

Oh Refrigerant is now R507a 1st stage and R1150 on the 2nd.

The compressors i got for £40 from a Air con unit which was removed from a office. :D Both work superb and 1 of them being in new condition due to a re-install on the unit i reckon. :D

The rubber mounts for the compressors are a pain to get hold off. Anyone have a shop that stock them for these compressors? :D

Looking to that other site I now see another problem with picture 3.

You have ran the system and frozen the outside of your Heat exchanger, but unfortunately you didn't seal the pipes for the 2nd stage and also would have created lots of frost on the inside of the pipes.

Next time, seal the pipes before testing.

Also, the comp sounds wrong in your video clip. It sounds like the internal springs have came off and the motor is rubbing against the casing. (would you like to post the clip here for others to hear?)

Chillin:) :)

4Qman,
Leave some form of acess to the suction side. Take off the schraders and use "hand valves", not ball valves.

Most anybody with refrigeration experience can get a cascade to work, No disrespect intended to anyone. The trick is to increase the longevity of the system.

the factory cascades that i repair have an average life span of 8 years +. Our rebuilds on the same units have a life expectancy of 5 + years. The temps and the equipment are unforgiving and it all comes down to the details in the process.

Your worst enemy is moisture in the system. Your best freind is vacuum and dry nitrogen. Try to achive a vacuum of less than 100 microns/millitorr. You should be able to blank off and remaine under 400 microns for 30 minutes. Get rid of the charging hoses and and use copper line from the manifold to the unit and to the vacuum pump. Charging hoses wil not let you achieve a deep vacuum because of the material they are made of, they constantly off gas.

Your kung fu looks good, Now lets make it last.

My cascade running "Download a free user"
http://rapidshare.com/files/29054309...ge_running.AVI

It hasnt any mounts on the bottom of the cascade. It did sound nice when run but now a little nosiey?

I know i did a wrong move with the HX not being capped off. Wont do it again. I vacuumed it for a few ohs and blasted through with nitrogen to be sure.

Does the compressor sound nackard then chilling out?

Yes, it does.

Think of a motor spinning round inside held in place with 3 springs, now remove a spring and the motor falls to one side and rattles against the casing.
Someone might have a picture for you to see.

Did you drop the comp at any time?

Chillin:) :)

Did you drop the comp at any time?

No mate, was sounding sweet as a nut then i fixed it all together with the build and now it sounds a little doggy to say the least. :rolleyes:

Its working correct as in temps and pressures. Whats the downfall regards running it if it is as you mentioned?

Quote:

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Whats the downfall regards running it if it is as you mentioned?

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Well you already know about the noise...lol

Eventually the internal pipes will rupture and render the comp useless.

Any chance of sending it back?

Chillin:) :)

Quote:

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Originally Posted by chillin out

Well you already know about the noise...lol

Eventually the internal pipes will rupture and render the comp useless.

Any chance of sending it back?

Chillin:) :)

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No mate, i got it from a air con unit that was office clearance. I got it along with the other unit that is fine.

Dam man, gutted to say the least. I don't suppose anyone has a compressor that kind of power floating about.:)

Just when i was ready to complete the 2nd stage this weekend. :o

chillin out
I thought i would mention. When the compressor was fired up without any refrigerant inside it run quite and nice and smooth.

However now its very loud as you know from the video. Could this be due to the pressure in the first stage? 90PSI Static 200PSI Running IDLE?

When i claim some refrigerant back which lowers the pressure it sounds a bit better. :)

I am just trying to convince myself its not focked :o

Quote:

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No mate, i got it from a Air con unit that was office clearance.

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That might be a problem for a start, A/C comps run at high back pressure, you want low back pressure.

Are you still running the system with hard frost coming back to the comp?
Have you insulated the TEV sensor?

Hopefully someone else will comment.

Chillin:) :)

Quote:

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Originally Posted by chillin out

That might be a problem for a start, A/C comps run at high back pressure, you want low back pressure.

Are you still running the system with hard frost coming back to the comp?
Have you insulated the TEV sensor?

Hopefully someone else will comment.

Chillin:) :)

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Firstly, thank you for your input. Be nice for some more comments on the subject in question to get other opinions. "I respect yours and i am taking them seriously"

I have run the unit once or twice for around a hour or 2 in total.,

The Bulb from the TEV isnt insulated and i am running the unit with it frosting back to the compressor housing. due to it having a high load once the 2nd stage is charged and running.

Pressures
Low=3PSI
High=168PSI

Temps:
6" From Suction = 31.8oC - super heat is 9K UNINSULATED.

This is on 1st Stage Using R404a which is a 1 & 1/2HP "34cc" Compressor.

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The Bulb from the TEV isnt insulated and i am running the unit with it frosting back to the Compressor housing.

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Insulate it then!!!....lol

Do you know what happens when it gets insulated?

You will not lose any cooling capacity in the HX, quite the opposite. If you insulate it then the TEV will have better control over the refrigerant flow and evaporating temp. This will close the TEV causing a lower suction pressure thus dropping the evap temp at the same time.

So if you are saying the noise calms down a bit when the suction pressure is lower and you also want a colder evap, then insulate the TEV bulb.

If you have frost on the suction line going back to the comp, then it's OK so long as it's only caused by very cold gas. If you still have liquid boiling off then your system is not set up right.

Only trying to help.

Chillin:) :)

Well, she certainly don't sound too healthy :(

That noise kinda sounds creamed bearing or similar.

Chilling Out.
dude i havent insulated it yet as the units not finished. I only powered the unit to make sure it would run and i didnt spend any more time on it due to the noise situation.

Ultra.
Thanks for the input. Emm looks like i will be shopping for a new compressor this weekend then. :cool:

While you are waiting for a new comp, recover the 404a. Recharge 2 oz of 134A, then follow up with 404a. Do a static charge of the 404a to about 60 or 70 psi. Remove the TXV bulb from the sution line and let it set in the air. Adjust the TX closed. Put a thermocouple inbetween the TX and the evap (TC1). Install another on the suction line 2 inches from the evap (TC2). Start the system. Adjust the charge of 404A.

What you are looking for is
Head pressure of about 125-175 psi.
Suction pressure of 5-10 inches of vacuum
TC 1 temp of -35 to -45c
TC 2 temp within 1-2 degrees c of TC1
Watch and make sure that teh frost line stays about 4-6 inches away from the comp.

If the head pressure is above 175 PSI and the suction is more than 10 inches of vacuum, then open the TX. If the head pressure is less than 150 PSI and the suction is more than 10 inches, adjust the charge of 404A.

Quote:

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Originally Posted by ultralo1

While you are waiting for a new comp, recover the 404a. Recharge 2 oz of 134A, then follow up with 404a. Do a static charge of the 404a to about 60 or 70 psi. Remove the TXV bulb from the sution line and let it set in the air. Adjust the TX closed. Put a thermocouple inbetween the TX and the evap (TC1). Install another on the suction line 2 inches from the evap (TC2). Start the system. Adjust the charge of 404A.

What you are looking for is
Head pressure of about 125-175 psi.
Suction pressure of 5-10 inches of vacuum
TC 1 temp of -35 to -45c
TC 2 temp within 1-2 degrees c of TC1
Watch and make sure that teh frost line stays about 4-6 inches away from the comp.

If the head pressure is above 175 PSI and the suction is more than 10 inches of vacuum, then open the TX. If the head pressure is less than 150 PSI and the suction is more than 10 inches, adjust the charge of 404A.

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Would this give the ideal charge and running or determine how the compressor is functioning?

It is for the charge. The idea is to flood the evap and get it as cold as possible without letting the liquid refrigerant get back to the comp. Also to help miniumize the stress on the comp.

This "playing" with the charge and the TX will, in my opinion, help you understand what is happening with the components of the circuit and see what relationship they have to each other. Once you have a good idea how everything relates, then you can "tune" the system.

Mind you I am not an engineer, I am a tech. My approach is different. If you think the comp is going bad why not play with the system and have a chance to learn.

Oh yeah, do all of this without the second running. After you are happy with the temp of the first then turn on the second.

Does anyone know if running the compressor without the correct capacitor would cause it to run as it was in the video. ie loud as hell.

Just i have been using a different rated capacitor which i forgot to mention,. :o

Nah, wouldn't make that noise. The only problem it would cause is that it wouldn't start up and premature electrical failure.

Try, if you want, tipping the comp to one side which should take the inside part away from the casing which might stop the noise.

(and insulate the TEV bulb....lol)

Chillin:) :)

Quote:

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Originally Posted by ultralo1

It is for the charge. The idea is to flood the evap and get it as cold as possible without letting the liquid refrigerant get back to the comp. Also to help miniumize the stress on the comp.

This "playing" with the charge and the TX will, in my opinion, help you understand what is happening with the components of the circuit and see what relationship they have to each other. Once you have a good idea how everything relates, then you can "tune" the system.

Mind you I am not an engineer, I am a tech. My approach is different. If you think the comp is going bad why not play with the system and have a chance to learn.

Oh yeah, do all of this without the second running. After you are happy with the temp of the first then turn on the second.

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You do that with CPEVs not TXVs <_< reseting the SH on a TXV is a pain, don't mess with it! A thermal static automaticaly adjusts refrigerant level in the evap, IE there is no critical charge in such a system.

Quote:

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Originally Posted by The MG Pony

You do that with CPEVs not TXVs <_< reseting the SH on a TXV is a pain, don't mess with it! A thermal static automaticaly adjusts refrigerant level in the evap, IE there is no critical charge in such a system.

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Thanks for the input dude. I seen you about on XS ;)

Ok on hold for a bit until 1st compressor can be replaced. :o

Quote:

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Originally Posted by The MG Pony

You do that with CPEVs not TXVs <_< reseting the SH on a TXV is a pain, don't mess with it! A thermal static automaticaly adjusts refrigerant level in the evap, IE there is no critical charge in such a system.

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I was not saying to mess with the SH. I did not explain myself to well. I stated that you should let the tx bulb hang in the air. This in effect gives you a fixed orifice, this way you can see the effects of charge.

I would strongly suggest putting a suction accumulator on the first stage when using a TX. This will keep flood back to a minimum

Oh Ok that makes allot more sense!

In a TXV set up flood back should never be an issue as it is designed not to allow it, how ever experimenting in the way you are suggesting to him it would be a wise precaution. That's the nice thing about TXVs, is how forgiving they are about charge less you use a system with no receiver.

Excellent system Fat Boy, a little off topic, but has anyone tried using a 3phase compressor along with a single phase to 3ph motor inverter to create a variable speed compressor, much like inverter air conditioning units. One thing I don't get is that they say "DC inverter" when on the tech docs, the wires to the compressor are labelled U, V and W, same as a mitsubishi motor inverter that I once had.

With software or a PLC to control the inverter, you could have a nice variable cooling system that reacts to the temperature of the target (CPU in this case).

I've sold the motor and inverter now but here was a video I shot: http://electro.ath.cx/temp_files_to_...r/MOV04066.wmv

Cheers! & Sorry, didn't want to come across as a thread hijack!! :)

nice work lads

iam sure ive a few rubber mounts for the compressors in that junk yard,i mean van will have a look for you

Thanks people. Build be complete soon enuf ;)

you are simply great thanks

Ohhh my dears, this seems like one of the best and coolest proyects I have seen so far. But me and my ignorance make ask some stuff like. If this 2.5 HP system is for cooling a processor and just one processor around -100ºC or so.
1.- Do you need to turn on this cooling system always or have a "fan cool" when you are just reading the email.
2.- Whath type of extreme calculations or work is made in one of this CPU... and the limit speed ???

Just curios, Iam as well a designer and use a big and bad cpu ...

cheers!!!