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Cooling Phase Change Guide

Discussion in 'Hardware' started by Marvt74, 19 Sep 2005.

  1. Marvt74

    Marvt74 What's a Dremel?

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    I figured there should be a thread with the basics/links for reference purposes.

    What is Phase Change?

    The compressor compresses the refrigerant into a high pressure... Where in the condenser, it condenses to a liquid under high pressure and also at the same time gives up its heat. It then travels to the liquid line, where liquid refrigerant usually travels through a filter/dryer, which filters out particles and is a desiccant, meaning it absorbs moisture. From that point, it travels to the metering device, usually either a capillary tube, or Thermal Expansion Valve (TXV). These regulate the flow of the liquid refrigerant, because at this point is under far too much pressure to evaporate. Once it leaves the metering device, it enters the evaporator, where the liquid refrigerant boils off, sucking up the heat with it. It then travels down the suction line of the system, back through the compressor, and into the condenser.

    What phase change system should I buy?

    The 2 common systems are a Prometeia Mach 2 and an Asetek Vapochill. You can then build your own if you have the knowledge and tools and with a little reading this can be done on your own. I will hopefully be doing this soon and will include a write up of my progress.

    How much will a phase change system set me back?

    A new bit of kit will cost about 450ish for a Vapo LS or Mach 2 GT, with a standard Mach 2 being slightly less. However if you manage to pic us a used system you are likely to get a bargain as people tend to sell there used systems scarily cheap and a Mach 2 GT can be had for about £200, and an old Mach 1 for about £130 which is cheaper than a good water setup and much better.

    So there are only 2 types?

    Yes, there are 2 kinds of phase change, direct die and waterchilling. Direct die is covered next and waterchilling will be covered at the end of this guide.

    So what kind of direct die systems are there

    Well yes and No, There are 2 main companies in the field Nventiv also known as Ecold and Asetec who are better known for their waterchill kits. Both manufacture different levels of systems as shown below

    Nventiv

    Prometeia (Formerly Mach 2)

    These are entry models and are charged with R134 refridgerant, they usually get to about -40.

    [​IMG]

    Prometeia 2 (Formerly Mach 2 GT)

    This is a beefed up version of the standard Mach 2, it is charged with R404 refridgerent and gets to about -60. It looks identical to the standard prometeia


    Asetek

    Asetek have many models (classic, pe, xe, ls), however only mainly produce the LS nowadays

    Asetek Vapochil LS

    This is on par with the Mach 2 GT and is charged with R507 refrigerant and also gets to about -60. It to comes with silver aluminium panels though they do not have the same style design as the lian li cases.

    [​IMG]

    Older Vapochill (Classic, PE, XE)

    These were charged with R134 and came in their own cases which were pretty damn ugly if you ask me but did the job. They were also quite cramped inside I found.

    [​IMG]


    Which is the better choice then?

    Well as with all computer genres there are 2 main contenders fighting for your wad of cash. (ATI vs Nvidia, AMD vs Intel etc)

    And with these come the fanboys of each. So you will never really get an honest opinion if you ask on a forum.

    I prefer the Mach 2 range (partly because asetek called there water cooling kits waterchill which they aren’t but I’ll explain why later.)

    The mach 2 range seem to give better temps when the heat load is under 200w as most chips are. However with the new FX57 range the LS seems to give slightly better temps on the heavily overclocked FX57’s whereas the mach2’s have been known to get into positive temps :eek:


    Can I use phase change to cool the Graphics and NB aswell?

    Initially no, the commercial systems only have 1 evap head for cooling the CPU.
    Systems can be modded to include extra evap heads if you find someone willing to do so or have the tools/knowhow to do it yourself.

    It is also not advisable to use phase change on the GPU 24/7 as they do not produce enough heat so battling condensation is quite a tricky process. Unless you tune the system to ~130W so that it will be adequate.

    Phase is usable on the GPU for however for benching purposes where the card is practically always under load and isn’t ran for very long at a time. Though beware this is very high risk.

    There is also a UK retailer that is capable or modding systems and can tune them to a set heatload. However they only have a SLI setup so it only caters for the GPU and a separate system is needed for the CPU. This is a much better way of doing things since current GPU’s can kick out over 100w of heat so when you add a cpu ~200w your going to hit problems and get poor temps.

    [​IMG]

    There are options however for triple headed systems (cpu/gpu/nb) and they can be found over at VR-Zone

    [​IMG]

    This however is unlikely to be very effective as your cannot tune each evap head to a specific heatload so the cpu will be in positive temps.

    A common idea amongst phase change users is to use phase change for the CPU and then either pelt or just watercool the gfx/nb as seen here

    [​IMG]

    Is there any way of getting even colder?

    Yes there are many ways to get your phase change system colder.
    The most common is to regas your system with another type of refrigerant. Another if you have any brazing skills is to replace the standard evap head with a chilly1 head. Or finally you can enter the world of cascades.

    What is a chilly1 head?

    Chilly1 is a member of several boards and is often seen moderating over at XS. He is a HVAC engineer and is widely known around the Phase change community.
    He builds cascades and single stage systems over in the states.
    He has also engineered his own evap head which he sells ~$100. This is a great design and can give improvements over the standard head.

    What does regassing do?

    As can be seen above the basic models commercially available contain R134 refrigerant. Whereas the higher end models contain R404 refrigerant.

    So if you have a R134 system, regassing to R404 can give good improvements.
    Many people upgrading their systems however go for R507 as it is widely available and has a lower boiling point than R404 thus giving colder temps. Then you begin to get into the tricky world of blends of different gases but when the experts find a blend which works nicely they often keep the amounts to themselves. Although a blend of R402 and R507 give good results but its tricky to get he ratios.
    Please also bear in mind that on old vapochill systems (the XE and PE anyway) when regassed with R404 as many are, once shut down you will have to wait ~40 minutes before switching on again.

    Also when regassing with R507 on the mach 2's fans need to be fan at turbo making it ~40db

    What is a Cascade?

    This is where my current knowledge is pretty damn sparse and can only give a little information though I’m gonna guess if your reading this your not gonna jump into using cascades anyway :p

    Cascades basically consists of cooling the condenser of one system with another system.
    There are 3 kinds of cascades
    Autocascade
    Cascade
    Triple stage Cascade

    Autocascade – Can Get you down to about -80
    Double Stage Cascade – Can get you down to about -100
    Triple Stage Cascade – Can get you to -120 often even colder still.

    As I say I know little about cascades but will update when I get some more reading done. But can say now they ain’t cheap.


    I’ve used all the above and want to try my hand at something different what is there?

    Well now your gonna enter the world of Dry Ice and Liquid Nitrogen but that ain’t gonna be covered here. Theres plenty info out there though.
     
  2. Marvt74

    Marvt74 What's a Dremel?

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    So what is a waterchiller

    These are similar to the direct die systems but the coils are used to cool a big reservoir of water and thus can be used in water loops to cool all the cpu, gpu and nb to nice cold temperatures.
    These are much more hassle however as all tubing and blocks must be proofed against condensation as all tubes will be below ambient temps rather than pelts where only the block is cold.

    A typical waterchiller can be seen here

    [​IMG]


    How cold will the water get?
    This is relative to a lot of things, such as your capillary tube length, the gas your using, the power of your compressor, etc. Several different things going into determining how cold your water will get. You can be assured one thing though, it will get cold.
    Expect about 0.2C water temps on average.

    How cold will it keep my CPU?
    Again, another relative question. This is also dependent on many factors, such as the effeciency of your waterblock, the thermal interface material used, how well things are insulated, etc. Generally, at idle, your CPU temperature should be about that of the water, and at load, maybe a few degrees celcius higher. The CPU will eventually heat up your water, and its the job of your chiller to keep it at an acceptable temperature. This is where the capillary tube comes in. The shorter your capillary tube is, the colder your initial temperature will be. But as soon as you put a cpu load on it, it will shoot up. The longer it is, the less change in temperature from normal water to heated water is. Your goal is to find a happy medium.

    What should I put in the water?
    Straight water is the best coolant, but since were going sub zero temps, we cant use straight water, it would freeze. Antifreeze is good, which is glycol. There is methanol, which is windshield wiper fluid. Denatured Alcohol is good as well. You can get 100% methanol in gas line additives to stop gas from freezing. Be careful, the last 3 are very flammable. The trick is a water flow. Streams and rivers dont freeze at freezing temperatures, only when its REALLY cold. This is because the water is flowing, and its harder to freeze that way. The best thing to do is have a mix of flow and water additive.


    What kind of waterblock should I get?
    Whichever waterblock you think is the best... Try and get one that is aluminum, copper, or brass topped, as plexiglass and lucite can crack under extremely low temperatures.

    What about a radiator?
    There is no radiator in this watercooling system... If there was, it would waste precious degrees just putting cold into the air. There is only a resevoir.

    What about condensation

    This a large factor in waterchilling as it is not just the chip which is lower than ambient temps (like when using pelts) the tubing and whole blocks must be well insulated as seen below.

    [​IMG]

    This concludes this guide, thanks for reading it and hopefully its been informative.
    If theres anything incorrect please let me know and I’ll correct myself.
     
  3. slaw

    slaw At Argos buying "gold"

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    nice guide! very intresting read!!
     
  4. M_D_K

    M_D_K Minimodder

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    Thats top notch :) good guide there think this needs too be stickied :)



    morgan.
     
  5. Nexxo

    Nexxo * Prefab Sprout – The King of Rock 'n' Roll

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    Stickified. :thumb:
     
  6. Shadowed_fury

    Shadowed_fury Minimodder

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    Excellent guide! As if watercooling wasn't scary enough :)
     
  7. Top Nurse

    Top Nurse Minimodder

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    I love it as while I am interested in PC it always seemed too much trouble to run around all over the net trying to figure out how it all works. Thank you vey much for making it nice and easy for us mundane watercoolers. :dremel:
     
  8. fatty

    fatty Minimodder

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    Nice to see some of my work on here [​IMG]

    Also the same UK site make waterchillers based around the mach2 more pictures and builds can be found HERE

    P.S Great guide
     
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