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Thread: 1/2+ hp Single Stage Build

  1. #26
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    I have to say that I am impressed from its overall performance, its way better than the first SS that I built.

    Core 2 Duo E4500 stock @ bios



    E4500 2.2 @ 4.4GHz (1.9v, -42.5C)


  2. #27
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    Yeah that is working great, very nice! Oh and you're right, it should do even better when your ambient temps are cooler.
    Last edited by aenigma; 08-06-2019 at 06:36 PM.

  3. #28
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    You have a lot of CPU's to test, might as well send me some hardware to test on my autocascade!

  4. #29
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    Quote Originally Posted by aenigma View Post
    You have a lot of CPU's to test, might as well send me some hardware to test on my autocascade!
    No problem, I have about 30 (different) s775 CPUs to send you if you pay shipping! I am from Greece!

    Last edited by Obijuan83; 08-08-2019 at 07:29 AM.

  5. #30
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    Oh wow nice, you have quite a collection! I was just joking about sending me hardware though haha

  6. #31
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    New mounting kit




  7. #32
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    Nice, it looks good!

  8. #33
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    Ambient temp 26C

    No load Evaporator temp -52.7C

    Last edited by Obijuan83; 08-16-2019 at 01:38 PM.

  9. #34
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    Nice, looks like it's working very well.

  10. #35
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    The ambient temp falls so I have this...



    The problem is that despite the fact that the no load temp is 54.4 it cannot maintain the load that could hold when ambient temp was higher.

    And to give some numbers:

    With ambient temp 29-30 C I had high pressure before condenser about 40C.

    With ambient temp 24-25 C I have high pressure about 36C

    What this means? Long cap tube or not enough refridgerant?

  11. #36
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    First I would try adding some more refrigerant since that is easy to do, but my bet is on the cap tube being a bit too restrictive since the high side pressure is lower now that it is cooler and there isn't as much mass flow anymore.

  12. #37
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    I tried to cover 2/3 of the front condenser surface so the airflow can pass only from the remaining 1/3 and the high side pressure rise from 200psi/35C to 230psi/41C and the difference was huge.It can hold the load even better than before!

    Is that gives you a clue about what is the "problem"

    I tend to believe that its a little undercharged.

  13. #38
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    Yeah it very well could be undercharged that's why I said start by adding some refrigerant and see if that helps since it's easy to do. Do that with full airflow though. If it doesn't help then you just need to shorten your cap tube a little bit. The higher pressure on high side from blocking the airflow will push more refrigerant through the capillary so it is very likely your cap tube is just a little bit too restrictive.

  14. #39
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    Will try add some r404a...!

    No load temp


  15. #40
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    You need to add it under a load slowly to see if it helps. Add a little under a load then let it run that way for a few minutes and see if temps fall. If not then the cap tube is too restrictive.

    <edit>
    I just wanted to add something interesting/funny that just happened. I was wanting to do some low stage work on my autocascade/MRC and I was pumping it down by closing off all the stages and it looked fine but I got sidetracked and when I came back the high side needle was absolutely pegged. It goes to 500psi but it was past that touching the stopper. Compressors still sounded fine luckily, but what a good test of high side lines.

    I usually pump it down into a cylinder while doing this, but it didn't look like it was needed at that time but then I got pulled away doing something else. Very interesting to see that happen with the alleged "bomb" I made in any case.

    What I mean by "bomb" is there were some old old threads on here back when I made this autocascade that had people posting things that had, ehh, let's say, less than reasonable understanding, claiming people would blow themselves up making a nitrous/propane autocascade haha
    Last edited by aenigma; 09-10-2019 at 10:49 PM.

  16. #41
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    My Ryzen 7 2700 under my Single Stage!

    4.7GHz (1.45v , -40C)




  17. #42
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    Just a question... where is your temp probe mounted at ?
    It appears like it is on the suction line just behind the evap, I say this because -55.9C on a single stage should not be possible, I might be incorrect. In all the years I have been running SS Phases units I have not seen a unit run at those temps and even be remotely able to hold a load. Most use R507 now, or even something different as in the states I believe they changed what could be used. Will have to get a pro builder in here to give feed back on the temps. I believe temps actually get colder as the gas gets pulled through the evap into the suction line, but that's not the temp inside the evap near the CPU.

    The probe should be mounted at the base of the evap, near the CPU, some even drill a hole into the base of the evap and mount it there.

    I have a monster SS Stage built by Ron, it pulls -45C with probe mounted like I said.

  18. #43
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    The probe is properly calibrated.

    Its mounted at the side of evap near the base.

    The temp at -55.9 is no load evap temp with the SS slightly undercharged.

  19. #44
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    Yeah -55c and even lower is very possible without a load Buckeye. His post right above yours said -40c which I am assuming is under a load. That seems about right and it isn't actual CPU temp, there can be quite a big difference with the small surface area of the CPU die. I don't know how many watts of heat a Ryzen puts out since I am not into overclocking anymore and very much out of the loop.

    Back when I was using one of the single stages I made I was getting around -40c/-45c cpu die temps under a load, of course that was with Propane, nothing good like R-404a. I am guessing these new CPU temperature diodes aren't accurate at low temps anymore and you have to go by evap temp only?

  20. #45
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    Ah ok, I missed that post before, thanks.

    When Ron tuned my unit I asked him to tune for load, I believe it was for 300watts, maybe a bit more, -40c/-45c is what it does.

    Very nice and clean unit you built, good luck with tuning !

  21. #46
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    Under Load mine holds -40C to -42C @ ~ 300W

    Thanks for your comments Buckeye, it was my first SS that I built!

  22. #47
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    You did great !!
    Very nice clean build you did

  23. #48
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    it?s a bit unreal what you say , NEK2150gk has only 12ccm ...with souch small compressor at 300W you can -25 to -30 at 300w heat load hold!

    also your condenser is to large for this compressor , your condensing unit was projected for another load with an large evaporator , using it in low back pressure application like OC with small surface area evaporator , that condenser is way to large ...and you will heavly deep enter in the superheat issue.
    using cappilary tube as XV ...is usless using an sight glas , because you will have both liquid/gas at enter of cap tube anyway ....sight glas / reciever is mandatory when you refill a unit that actually use an TXV as expansion valve.

    also using a copper reciever as accumulator in suction sided , will not work as a right "accumulator" .. you will have anyway liquid refrigerant flood back intro the compressor and oil issue.

    regards!

  24. #49
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    Quote Originally Posted by nachtfalke View Post
    it?s a bit unreal what you say , NEK2150gk has only 12ccm ...with souch small compressor at 300W you can -25 to -30 at 300w heat load hold!

    also your condenser is to large for this compressor , your condensing unit was projected for another load with an large evaporator , using it in low back pressure application like OC with small surface area evaporator , that condenser is way to large ...and you will heavly deep enter in the superheat issue.
    using cappilary tube as XV ...is usless using an sight glas , because you will have both liquid/gas at enter of cap tube anyway ....sight glas / reciever is mandatory when you refill a unit that actually use an TXV as expansion valve.

    also using a copper reciever as accumulator in suction sided , will not work as a right "accumulator" .. you will have anyway liquid refrigerant flood back intro the compressor and oil issue.

    regards!
    I told him to get rid of that sight glass and receiver awhile ago and I believe he did and it started working much better. Also I am quite sure these 300w heatloads are not right. Just look up what CPU heat loads are and none come close to that. They keep dropping all the time after every new CPU infrastructure upgrade, not sure where 300w comes into play. Pretty sure it's closer to 100-150w heatload.

    A large condenser isn't a problem if the cap tube is correct, in fact it is better since it increases COP. Lower COP increases efficiency. This isn't an air conditioner or refrigerator that always runs at hi pressure and high temps, these are dialed in for certain conditions. When ambient temperatures change, then bad things can happen of course.

    Not sure what you mean about a receiver as a suction accumulator? Been a long time since I have checked the pictures, is that something that is present?

  25. #50
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    not condenser increase the COP ( coeficient of performance) , the XV will do that in this case the cape tube ...a small inleet of the cap tube will increase better the COP ....
    this large condenser will not help him to much ..-because the evaporator is too small , this is the main problem of the OC condensing units ...units are not as should be efffient because of the small area of the evaporator , the evaporator can?t take right the heat from the cpu/gpu because of his small surface area with the heat ..because of the evaporator base you have only a small roen of refrigerant , if the evaporator willl be larger then that condenser will fit , from my experience ( i work in refrigeration domain) i can tell you large condenser is not the way , i can do same with half of that condensor capacity ..will be more efficient! less weight and much more compact unit.

    about "accumulator " well many of the "builders" use for reciprocatings copper filter mounted in the suction sided , but he will not work as a dedicated accumulator .... please clik the link bellow , how a accumulator should be...
    https://forum.lab501.ro/showpost.php...09&postcount=8

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