CrossFlow Evaporator

[Sweeper]

Thought I would share a little project I'm working on. I decided to make a few evaporators and mounts, but as always with a little more xtreme. :D First the evaporators are made from 2" diameter copper and heights range from 1 7/8" to the "big mama" 2 1/4". The design of the evaporator is for refrigerant to enter from the bottom and make a full circle and step up to the next level and continue to circle the evaporator and exit at the top. I call it the Crossflow...after the low temp water blocks I made for Goliath. Also, the temperature probe will be at the bottom and center of the evaporator to get the most accurate temperature reading.

I've had this design on the table for awhile, but just now getting time to make the evaporators. I will be making universal mounts for these evaporators, but I have little surprise with the design. ;)

What do you guys think?

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[teyber]

awsome 4 axis machining there :O

was that done on a manual mill!?!?

2 1/4" tall x 2" diameter.. those are big evaps :) can't wait to see the mounting. ive played around with similar ideas but they would have taken to long for me to make on my small mill. id try to make a brazing ring on them... after lots of attempts with slide over its just a pain to have to re-surface the base after brazing.

whats the channel thickness and the base thickness? i think you could get away with less then half the heigth... and im not sure how a base that thick will work out.

great machining my friend :)

edit-

what i ment with the brazing ring is have the OD's be the same... hard to explain why... maybe you have better luck brazing them them me

[Sweeper]

awsome 4 axis machining there :O

was that done on a manual mill!?!?

2 1/4" tall x 2" diameter.. those are big evaps :) can't wait to see the mounting. ive played around with similar ideas but they would have taken to long for me to make on my small mill. id try to make a brazing ring on them... after lots of attempts with slide over its just a pain to have to re-surface the base after brazing.

whats the channel thickness and the base thickness? i think you could get away with less then half the heigth... and im not sure how a base that thick will work out.

great machining my friend :)

The evaporators were made with manual mill and lathe...alot of setup time and jigs to do this work.:yepp: I know the size might be overkill...but these babies shouldn't have any problem with removing heat and mantaining low temps.

The channels are 1/8" and the top channel is 3/16", the base is 1/4" thick. I will not be using a ring for the evaporator...the mount that I will make will be ringless :rolleyes: ... I think you will like the design. By the way, can forget about insulation around the evaporator too! ;)

[teyber]

nice :) Will you be recessing a 2" diameter ring in a plastic ring and cutting that in half and inserting that the mounting which has the same ID as the OD of the plastic with the 2" ridge in it?

interesting to see what you are thinking of with insulation :) i think your core temps will be very poor with a very thick base like that though...

[sjg0]

Wow looks really cool!

If i were you I would cut those channels just a bit deeper into the center, and as teyber said, I think I would make the base thinner.

Cool stuff though :)

[Sweeper]

Wow looks really cool!

If i were you I would cut those channels just a bit deeper into the center, and as teyber said, I think I would make the base thinner.

Cool stuff though :)

The channels are 1/8" wide x 5/8" depth. I can't go much deeper, because of the design of seperating the liquid and suction side. The vertical seperating bar forms a pie shape, when milled in a circle. Go much deeper and the two sides will be exposed to each other.

Why would a thinner base be better...I thought more mass would absorb more heat. Most of the evaporators made by other builders usually have a thick base.

[teyber]

whos evap in particular are you thinking of?

[wdrzal]

nice :)

interesting to see what you are thinking of with insulation :) ..

I pretty sure I know what he's going to do, wondered for years why no one did......I won't ruin his surprise ,you'll have to wait. :D ;)

[Sweeper]

whos evap in particular are you thinking of?

Chilly1 evaporator comes to mind and I've seen others in the forums. I'm still interested why thinner is better with direct die, I know thinner is better for low temp liquid block. The block I made for Goliath has a 1/8" base.

Attached is the chilly1 evaporator...the base looks to be close to 1/4" thick.

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[[XC] gomeler]

whos evap in particular are you thinking of?

Maybe one of Kayl's cascade evaps? Most evaps that I can think of have thin bases. Always wondered what a thick base would do though with a 3-stage cascade. Something like 1/2" base like a Kingpin F1EE liquid nitrogen pot :D

[sjg0]

The channels are 1/8" wide x 5/8" depth. I can't go much deeper, because of the design of seperating the liquid and suction side. The vertical seperating bar forms a pie shape, when milled in a circle. Go much deeper and the two sides will be exposed to each other.

Why would a thinner base be better...I thought more mass would absorb more heat. Most of the evaporators made by other builders usually have a thick base.

Ok ok. Sorry only quick glanced at the top of the evap.

Thinner base would be better I think because with a thicker base it would take a longer time for the heat to transfer across the copper. so when you fist turn on the computer, it will take a few minutes for it to cool down, and when u go from no load to full load, you will get bad temps because it will be harder for the coolness of the evap to combat the processor, you will almost have the cooling point in the copper base, and not on the surface of the cpu.

Sorry if im not making any sense. I understand it in my mind, just kinda hard to explain.

[sjg0]

I must say, your work looks SUPER clean though. :up:

[teyber]

gomeler;3272845']Maybe one of Kayl's cascade evaps? Most evaps that I can think of have thin bases. Always wondered what a thick base would do though with a 3-stage cascade. Something like 1/2" base like a Kingpin F1EE liquid nitrogen pot :D

this is not from a thermodynamic standpoint at all but...

tim- was telling me he was experimenting with huge evaps, pot sized with very thick bases. he said they got very cold but would slowly start to heat up. good for small runs.

jinu117 told me a certain thickness base he had found that if he went any thinner it would get expontially worse... It was much thinner then i had ever thought it would be

so maybe tom could enligthen us:shrug:

[andre X_X]

love the evap.... for evap like this its better to cool the center pole since it act as buffer and has direct contact with cpu core i think...

[HDCHOPPER]

beuuuuteeefull work man !

[gosmeyer]

Very nice!
Thats alot of hand wheel crankin let alone hittin the numbers

[piotres]

Nice idea :yepp:. Also quality look very good :).

[wdrzal]

Very nice!
Thats alot of hand wheel crankin let alone hittin the numbers

Thats the difference between a great old fashioned Machinist & Autocad & CNC . Not that their is any thing wrong with CNC, fast & highly accurate,it's just more PC based than cranking the wheels (Gray Matter based).

[Sweeper]

Thanks guys for the compliments. Its always great to hear positive feedback from experienced builders for all the hard work I put into my projects. I'm waiting on materials that should arrive this week and I will start making the evaporator mounts.

Wish I had a cascade to test the evaporator...but I don't, so I will use a tandem compressor set-up that I have setting in my shop. I need to make a dummy load tester. Can anyone suggest a cheap way to control watts of heater cartridges?

[ruffus]

i think you couold just use a dimmer switch
by the way sweet evap nice hand work for no cnc

[runmc]

Very nice work :)

I think a stepper design would be much easier to mill and you wouldn't have the dead spot along one side.
Do you find an advantage to this design over a stepper?

[teyber]

Thanks guys for the compliments. Its always great to hear positive feedback from experienced builders for all the hard work I put into my projects. I'm waiting on materials that should arrive this week and I will start making the evaporator mounts.

Wish I had a cascade to test the evaporator...but I don't, so I will use a tandem compressor set-up that I have setting in my shop. I need to make a dummy load tester. Can anyone suggest a cheap way to control watts of heater cartridges?

yes... you could buy a 120v, 250w cartridge heater and just give it 120v:up: but it will only be 250w... good enough for testing

[Sweeper]

Very nice work :)

I think a stepper design would be much easier to mill and you wouldn't have the dead spot along one side.
Do you find an advantage to this design over a stepper?

I don't know if my design will have advantage over the stepper or any other design. My intent was to design a evaporator that functions much like a coil evaporator. The vertical bar is not a dead spot, its part of the core and should get as much heat removal as any other part of the evaporator.

The stepper would definitely be easier to make, but I just wanted a different design than most builders use.

[Sweeper]

yes... you could buy a 120v, 250w cartridge heater and just give it 120v:up: but it will only be 250w... good enough for testing

So, this how most dummy load testers are made. I thought cartridge heaters needed to be controlled to maintain certain wattage or the copper block would continue to heat up above the required wattage.

[loonym]

Very nice machine work. Will be great to see some results.

[teyber]

you evaporator will have the refrigerant in it much longer then a stepper which is good. The way our load testers work is it gives out a certain amount of wattage at a certain amount of volts. the variable transformers allows you to choose whatever wattage you want but this way will be much cheaper but you are limited to 250w which is quite a bit

[theclash]

Great job on the evap!

In regards to the load tester, you can use a variac to control the voltage that you're sending to your cartridge heaters, 75 watt resistors, etc.

[chilly1]

Chilly1 evaporator comes to mind and I've seen others in the forums. I'm still interested why thinner is better with direct die, I know thinner is better for low temp liquid block. The block I made for Goliath has a 1/8" base.

Attached is the chilly1 evaporator...the base looks to be close to 1/4" thick.

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NIce block...

Thinner bases give you colder temps because of the thermal conductivity of the copper, thicker means you need a larger delta T to get the same BTU heat transferr. Larger Delta meant higher temperatures, As with LN2 the thinner Containers will get colder but will have issues on stability because you have to keep it full to get stability (Hard to do) the thick massive containers have a lot of mass to heat up. This adversely affects temperatures and capacity of refrigerating systems, so everything we do with Refrigerators has the thinnest possiable conduction surfaces limited mainly by the strength of teh material for stabil contact.

[yngndrw]

What kind of thickness should we aim at as a minimum to keep enough strength ?

[gosmeyer]

The channels are 1/8" and the top channel is 3/16", the base is 1/4" thick.

See how it works with what you end up with and I hope you have great results,:) But if they are less than what you had expected you might want to try to reduce the base by 20% +/- (5mm (.196") works well)

Thanks to Tom:D

[Sweeper]

I've finished the evaporator mount. As stated previously, the evaporator block will not require insulation, because the muff is made of a soild piece of PTFE ( Teflon ) and can handle temperatures to -200. The mounting plate is a design I made to represent the CrossFlow evaporator block and will be polished to a chrome finish.:D

Hope you guys like the build and comments always welcome.;)

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[passat]

nice

[vab206]

wow very nice!

[Nosfer@tu]

NIce block...

Thinner bases give you colder temps because of the thermal conductivity of the copper, thicker means you need a larger delta T to get the same BTU heat transferr. Larger Delta meant higher temperatures, As with LN2 the thinner Containers will get colder but will have issues on stability because you have to keep it full to get stability (Hard to do) the thick massive containers have a lot of mass to heat up. This adversely affects temperatures and capacity of refrigerating systems, so everything we do with Refrigerators has the thinnest possiable conduction surfaces limited mainly by the strength of teh material for stabil contact.

And I have to read that 2-3 Times to fully understand it :D :up:

Thx for the info

[teyber]

how did you cut that? did you lay it all out and mount the plate at a 45 degree angle to the table? if you don't mind me asking what type of plastic is that, and any pics of the no-insulation around evap mount?
I think it looks awsome and i think the quality of that is even better... I personally think it would look nice painted/anodized black for a black/white with the sleeve...
cheers :)

[Sweeper]

And I have to read that 2-3 Times to fully understand it :D :up:

Thx for the info

I had to read it several times myself and I'm still a little confused. Because if the base is thinner to absorb heat better, then what happens if the core is thick? Does the heat transfer well from a thin base to a thick core? I guess its a trial and error thing.

Think I will make another evaporator with a 3/16" base as suggested, to test if 1/16" will make a difference in base thickness. This has brought up some interesting concerns, so I think I will make a refrigeration system to only test different types of evaporators and see if I can find the golden one.;)

[teyber]

I had to read it several times myself and I'm still a little confused. Because if the base is thinner to absorb heat better, then what happens if the core is thick? Does the heat transfer well from a thin base to a thick core? I guess its a trial and error thing.

Think I will make another evaporator with a 3/16" base as suggested, to test if 1/16" will make a difference in base thickness. This has brought up some interesting concerns, so I think I will make a refrigeration system to only test different types of evaporators and see if I can find the golden one.;)

try even thinner:up:

[Sweeper]

how did you cut that? did you lay it all out and mount the plate at a 45 degree angle to the table? if you don't mind me asking what type of plastic is that, and any pics of the no-insulation around evap mount?
I think it looks awsome and i think the quality of that is even better... I personally think it would look nice painted/anodized black for a black/white with the sleeve...
cheers :)

I have several different jigs I made and X and Y axis rotary table. Trust me, its not easy to make. If people were interested in purchasing the evaporator kits, I would definently make the mounting plates on a water jet. I thought about having the mounting plates painted different colors, but for the first edition, I thought chrome finish would look nice.

The plastic is Teflon and it is the insulation for the evaporator block. Teflon can handle temps below -200, so no insulation is required around the block.

Later :D

[Blaster]

I hope you realize that if no insulation material is used you will have a swimming pool on the mboard :S

[Postal Dude]

Teflon will handle that temp yes. But it wont insulate down to that temp will it? The teflon will still get cold and sweat, maybe even frist up depending on how much cold gets through it

[Sweeper]

Teflon will handle that temp yes. But it wont insulate down to that temp will it? The teflon will still get cold and sweat, maybe even frist up depending on how much cold gets through it

Heres a quote from one of many websites that describes PTFE properties:

Polytetrafluoroethylene (PTFE), is a thermoplastic member of the fluoropolymer family of plastics. PTFE has a low coefficient of friction, excellent insulating properties, and is chemically inert to most substances.

Exceptionally wide range of thermal appli-cations from minus 260°C to plus 300°C, Virtually universal chemical resistance, Light- and weather-resistant, Resistant against hot water vapor, Excellent sliding properties, Anti-adhesive behavior, Non-combustible, Good electric and dielectric properties and No absorption of water.

As described above, I think PTFE is a great product to use for the evaporator, due to the ability to handle extremely low temperatures, no absortption of water and excellent insulating properties.

Hope this helps and only testing will give true results, which I will share with everyone.

Thanks

[Sweeper]

I hope you realize that if no insulation material is used you will have a swimming pool on the mboard :S

When I state no insulation required, hope you know I'm only referring to the evaporator block only. Naturally, the socket will need insulation as common practice with direct die application. So, there should not be any moisture between the evaporator block and chip.

[[XC] gomeler]

It'll be very interesting to see how it turns out, maybe you've found the perfect combined mount + insulation or maybe it's a step in the right direction.

[Blaster]

When I state no insulation required, hope you know I'm only referring to the evaporator block only. Naturally, the socket will need insulation as common practice with direct die application. So, there should not be any moisture between the evaporator block and chip.

No, im not referring to the socket.
From your photos you have like a 12mm wall of teflon, go ahead and try it but for the normal ss temps you will have water or perhaps frost on the outside, not even going for cascade temps hehehe.

Teflon has a thermal conductivity of 0,2 (W/m K), normal insulation materials have 8 to 10 times lower thermal conductivity.

Dont think im just being negative about it, ive tested many materials already. For example, styrofoam has a themal conductivity of 0,033, its "usable" but with evap at -50 and humidity above 65% it will start to form condensation, and thats using 18mm wall...

[Sweeper]

No, im not referring to the socket.
From your photos you have like a 12mm wall of teflon, go ahead and try it but for the normal ss temps you will have water or perhaps frost on the outside, not even going for cascade temps hehehe.

Teflon has a thermal conductivity of 0,2 (W/m K), normal insulation materials have 8 to 10 times lower thermal conductivity.

Dont think im just being negative about it, ive tested many materials already. For example, styrofoam has a themal conductivity of 0,033, its "usable" but with evap at -50 and humidity above 65% it will start to form condensation, and thats using 18mm wall...

Interesting information. What was the wall thickness and the lowest temp you reached, before condensation started when you tested Teflon?

[[XC] 2long4u]

I like it. :up:

[gosmeyer]

Can't have your cake and eat it too

[Sweeper]

Can't have your cake and eat it too

Not to sound rude, but thats a premature statement, without seeing test results. Don't you think.:rolleyes:

[sjg0]

Sweeper your work brings tears of joy to my eyes. Its, Its just so beautiful!

I cant wait to see some performance tests. Will you be making a few of these and putting them up for sale?

[gosmeyer]

Not to sound rude, but thats a premature statement, without seeing test results. Don't you think.:rolleyes:

Not So Much:D It's a fact of life

[Polizei]

I think what they are saying is that Teflon is good down to -200C, but it doesn't insulate. It just keeps it's properties like low friction,non-combustible, etc. at low temperatures. I don't think it's much of an insulator to keep the coldness of the evap from getting out to the environment.

Aside from that - beautiful work on the evap... very clean. I just hope this isn't delaying your chiller project... ;)

[Sweeper]

Sweeper your work brings tears of joy to my eyes. Its, Its just so beautiful!

I cant wait to see some performance tests. Will you be making a few of these and putting them up for sale?

Thanks for the compliment. Yes, I will build a few for sale, once testing is complete.

[Sweeper]

I think what they are saying is that Teflon is good down to -200C, but it doesn't insulate. It just keeps it's properties like low friction,non-combustible, etc. at low temperatures. I don't think it's much of an insulator to keep the coldness of the evap from getting out to the environment.

Aside from that - beautiful work on the evap... very clean. I just hope this isn't delaying your chiller project... ;)

The evaporator work is something I did for past time, until I get the remaining parts needed to complete the chiller. I received the aluminum to make the wiring harness mount and will make it this weekend. So, I hope to share some results soon.:D

[Polizei]

The evaporator work is something I did for past time, until I get the remaining parts needed to complete the chiller. I received the aluminum to make the wiring harness mount and will make it this weekend. So, I hope to share some results soon.:D

Eagerly waiting. :)