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Thread: DIY first time singlel stage

  1. #1
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    DIY first time singlel stage

    ok i started bulidng ss few years ago but never finished it, i got good evaporator with suction and capilar tube, but few days ago i got for really cheap mobile air conditioner, so i need to now could i use it.
    specs for compressor are
    - 12000BTU / 3,5KW
    - R407C (480g)
    radiator is also very nice and big with good ventilation, but what bothers me is lot of electronics, i would like to cut that all out so there is no regulator or other stuff.
    i forgot to mention its rotary compressor not piston like i wanted to use i think this one is better.

    tibor and littledevil help me alot before but i drop this a side but now iwant to finish it.

    here a re some pics



    here is my old thread here with my evaporator LINK


    thousands of questions are coming prepare your selfs

  2. #2
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    Those portable AC units are great for conversions. The compressor is pretty big but not so big that it's any issue and will give some pretty great temps.

    Changing the captube to something like 7-8' of .031" or 10-11' of .036" (or your metric equivalent) would be good.

    Your evap look ok, hard to see much in the pics. Seems more or less hollow, but if the base is thin enough (like 4mm give or take) then it should work well enough, especially if it's pointed down to let gravity help out as well. A hollow evap can be a bit weaker if the expansion area is large. If the chamber is shallow it helps.

    The electrics you can get rid of completely and just use any -50ish display with a switch Just rewire the fan and compressor, and wire in the display. If it's a 12v display you'd use, then a 12v laptop or whichever 240 to 12v psu would be fine.

    Just get rid of what you don't need, like the evaportator and fan for the top section and you may be able to make everything internally fit in the base. If that were possible you can make up basic panels if you wanted a sealed setup. Can often chop and reuse the original panels, especially if you don't really care if it's pretty, just that it works.

    If you can remove and save the gas, you could reuse the 407 for your unit as well. Not as cold as some, but if you can save and reuse, it's free.


    Gray
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  3. #3
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    that would make a nice first stage for a cascade
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  4. #4
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    thanks for great info gray mole

    here is my evaporator not that one form the first page, and i cant save the 407 gas because its just selaed i have to cut the pipe :S or there is antoher way.

    also on the evap picture there is capilar i hope a ican use it, i will tell you the diameter later... have lot morequestions later

  5. #5
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    Quote Originally Posted by Gray Mole View Post
    If you can remove and save the gas, you could reuse the 407 for your unit as well. Not as cold as some, but if you can save and reuse, it's free.
    R407C is such a pain in the ass for setting up, terrible glide and not as good as R404a for negative T, if he can move to another gas I think it'll fit better for that purpose ( first stage cascade of single stage ).

  6. #6
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    That's a decent looking evap. I mean, it may be a bit thick on the base, might not have great heat transfer compared to some, but it's sure better than a hollow evap

    If the base is really thick, like 5 or more mm, then you may find that at high load and longer load (like a long benchmark, extended gaming or video editing or something) it won't have as good cpu temps as some. If the difference between the cpu temp, and the evap temp is high at those times then one day a new evap could be good. But it look ok and you only ever know when you try it.

    The coiled captube could be good too. Hard to tell without measuring it. If you know it's size or can get it checked (there's a tool for that, and you could take it to a refrigeration store and they might let you borrow the tool. It's like a 'feeler guage' for tube sizing. Just a bunch of little 'spikes' with sizing so you can check the internal captube size.

    When you know for sure what it is, then you can cut the length you need.

    It's easy to gain access to the gas You just buy a 'vampire tap'. They make loads of kinds. Some are like a pair of vice grips with a piercing end, or the ones that bolt on. Cost around 10 dollars here, maybe 5-10 euro there, but you'd need something to pull the gas, and a bottle to put it into.

    http://www.ebay.ca/itm/Imperial-PT-1...item2eb93329b2

    That's a fancy vice grip type. You can buy ones that just bolt on cheaper but they're kind of 'throwaway' where these you can use over and over.


    Even if you made a small unit from anything, and used it to pull the gas out. Just 'spike' that one, and attach a line from the low pressure side of the unit you make to it, it would pull in all or almost all of it.

    Would need to vacuum the unit before using it to pull in the gas, but would also have to vac any unit, so that's nothing new.

    Making a basic gas recovery system isn't that hard though. Just a compressor and a bottle is all that's needed, as well as a pressure switch wouldn't be a bad idea. Even a compressor and a larger receiver if you could find a cheap one. Wouldn't hold much, but enough to pull gas to reuse it.

    But if you have that stuff and it's just the access to the gas in that thing, any kind of vampire tap will do it for you. Waste not want not When gas is 25 euro a kilo, may as well keep what you can.
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    Quote Originally Posted by Sk_rmouche View Post
    R407C is such a pain in the ass for setting up, terrible glide and not as good as R404a for negative T, if he can move to another gas I think it'll fit better for that purpose ( first stage cascade of single stage ).
    Oh yes, compared to some other gasses it's not as good. But if it's free then it's great to keep it. Beyond that, even if you don't use it it's good to keep. Test gas, or just slowly build up a collection of it if you buy them cheap and save the gas every time. If you can gather a full bottle of 407 over time, just sell it to someone else that can use it.

    But letting it into the environment is both illegal and harms the environment. If a person's going to make coolers, may as well do it right and save money in the process.
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  8. #8
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    heres a few pics od evaporator, capilar and gas refill position
    i cant measure inside of the capilar today maybe tomorow but i am sure you get the idea of the size ?


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    heres a few pics od evaporator, capilar and gas refill position
    i cant measure inside of the capilar today maybe tomorow but i am sure you get the idea of the size ?


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    http://www.supco.com/images/20%20cap%20tubing.pdf

    That's all in inches, but converting the 2mm OD of yours, you get .0787". I'm inclined to say that your caliper is reading just a tiny bit over that (a micrometer would be more accurate) and I'd have to say you have .031" or it's metric equivalent.

    http://www.supco.com/images/pdfs/Man...0Reference.pdf

    The supco guide for using captube's not really scoped out to what we're using it for. They have target temp vs. HP and we tend to go with Best temp vs. Capacity.

    But if you took the 1/5hp one, for -10 they say 54" of their no.1 (or .031") for an airco system.

    The basics of captube length sizing are there, and there's the captube sizing guide in the links on the phase guides on the main Phase Change forum page.

    All kind of out of date for the current spec. But if you have .031" cap (and I think you do) then around 7.5' is what I use for the 350w I go for. You may go a bit longer, bit shorter, and get the same thing.

    There's other variables affect it. Lighter gasses like R22 or R290, like shorter cap. Gasses with more mass like it a touch longer. But not a huge amount.

    You can use a piercing tap anywhere. May be hard to get it onto that little stub, but any place that's not right at the bottom of a pipe.

    If you spike into a pipe that's level at the bottom, you'll get a lot of oil with it. Nice to use a pipe that's on a bend, closer to the top.

    After you take out the gas, you can cut the part you've spiked into and replace the pipe, or just braze the little hole shut.

    When you do, I would use a pipe cutter and get rid of the old filter and stub, since it's a dual feed captube on that. Besides, it's always nice to use a fresh filter dryer and that looks like it's only a filter.

    Not uncommon to have a filter without dryer on a portable AC. I see window systems with no filter at all. Just a cap cut into the line.

    That evap's base is awfully thick. Takes a while to cool things down, and takes a while to recool after a bench test. 8mm is pretty huge.

    I've tested different evaps and with the tester gotten results from ones with different base thicknesses.

    What I found is that the thicker the base, the slower the movement of heat from cpu to evap.

    A thin base combined with good mass but good methods of heat transfer inside seem the best evaps.

    The Chilly1 and Kayl evaps so far prove best for the commercially made ones. I haven't tested Piotres newer ones but making my own now.

    Honestly though, I'd say just use it for now on your first one and see what it does. If you notice that a cpu that's got a lot of heat seems warmer under load and your evap seems cold, then it might be the evap, not the paste or the mount.

    Worst evap I used of the premade was the older Chilly1 series. The years ago ones with a super thick base. They'd get cold but it was hard to get heat through it from the cpu.

    A quick mod could be, if you have a dremel, is to try to grind the inner part of the base. You need the mounting ring, but if you could shave it down as much as you can it could help.

    I do that on evaps, and a roughened surface inside can help surface area and refrigerant exit speed. Longer you keep it boiling inside, more cooling happens there.

    Your caliper looks twisted on the base measurement, so you may be only 6 or 7mm but it's still on the thick side.

    Chilly1 and Kayl both, I think they're at a 4mm base.

    When I made my Daisy, I drilled to 3.5mm since I have the column support throughout the evap. Too thin and the base can warp in brazing or in use.

    So I'd say thinner is always better as long as you have the strength to use it, and some kind of mass to back it up.

    Gray
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  11. #11
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    Nice start ! With 12K rotary that will be strong 1st SS . Just get some R404a or R507 ...

  12. #12
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    ok, guy camed that works with AC and similiar and said that this is too powerfull compressor, so i am back with my aspera R12 250W compressor, i built down panel with whells and done the wiring, i also done the fan shield to guide the cold air. also the little panel with the power swtich and the cable connector, now i am waiting to my heater and variac to arrive.
    also mr. graham told me to help but no wrod from him for long time, so if anyone is interested to help via skype add me please.

    here is the video form today
    http://www.youtube.com/watch?v=rdAjM...ature=youtu.be

    evaporator will be the one from few posts up, and the capliary is 0,7 ?!?!?!

    help the noob thx

  13. #13
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    finally soldered, need final advices before purging the system, and its done!!!

    dejan

  14. #14
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    The filter/drier needs to be pointing down on the end the cap tube comes out of. And it's going to be hard to mount with the long piece of solid copper on the flex line. I would shorten the copper to about 1 inch maybe 1 1/2 inch.
    It's looking good though.
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  15. #15
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    Horizontal filter has never been an issue for me; just pointing up that can cause problemo's.
    But yep; I'd shorten the flex/evap distance as that will be impossible to work with.


    If you have a cooling question or concern feel free to contact me.

  16. #16
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    thx guys any advice on insulation or freon to use ???

  17. #17
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    Use r507 with POE oil and insulate everything that's on the low pressure side.
    UNDER THE ICE .com
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  18. #18
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    Or do a tester run with R290 (propane), you'll see what will ice, then insulate all of that.
    I would suggest not insulting till after you pressure test and get an ice run in because rare as it is, ocasionally you have a dead compressor or what not and then your just wasting insulation and all that jazz.


    If you have a cooling question or concern feel free to contact me.

  19. #19
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    thx

    guy that did soldering over 30 years in bussines doesnt want to put R507 in the system cause the compressor is R12, i said doesnt matter but he is convinced the compressor will die... now i have to find another guy for purging

  20. #20
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    heres little update

    http://youtu.be/6fMkT7WDwDQ



    more pics and video HERE

  21. #21
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    The compressor can die ofcourse, because the discharge pressure will be much higher when you use r507.
    Do you have the spec sheet of your compressor? What is the maximum allowed discharge pressure of your compressor?

  22. #22
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    hey man, no i dont any documentation only the numbers on the compressor, i hope it doesnt die, my hard work would go for nothing.

    i was thinking going R404 what do you think it has lower pressure ?!?!?

    here is what it says
    Aspera
    E1130B
    217NA02
    ?!?!??!

    http://freezingcenter.com/Aspera.html
    Last edited by dejanbinladen; 04-20-2012 at 11:28 AM.

  23. #23
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    Cant find much info on that compressor unfortunately...

    My guess is that a r12 compressor has a max condensing temp of 140* F.
    This equals a r12 pressure of 207 psi.

    When using r404 (or r507, the pressure is almost the same), this pressure of 207 psi equals a maximum condensing temperature of 90* F.
    Depending on the room temperature and the size of the condenser, this should be doable and the compressor will survive just fine.

    I have seen a lot of Danfoss NL11F phch units (r134a compressor) being recharged with r507, which run just fine.
    You are stressing the compressor more than intended, so early compressor failure can still happen.

    One thing I noticed was that your discharge line goes directly from the compressor to the condenser
    I would advice a winding in the copper pipe (like in the photo below), so the brazed connection doesn't get shaken loose by the compressor.
    vga-chiller.JPG
    Last edited by Jack; 04-20-2012 at 12:05 PM.

  24. #24
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    thx man you realy helped me here. i think i am going to use R404 next week but calculated capilary 1,5m (piotres aproved for 507 ) so would lenght be ok with 404 also cause there similiar ?

    and discharge what bad could happen if i left it this way ?

  25. #25
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    No issues with leaving it that way, it helps to add a coil for vibration dampening, but the braze isn't going to "shake loose" if its not. It just might be a bit noisier or transfer some vibration to the condenser.
    1.5m of what size? That seems way too short.


    If you have a cooling question or concern feel free to contact me.

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