The people I work with have started to call it "Mini-Me" :yepp:Quote:
I love the huge autocascade in the background. "Say hello to my little friend".
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The people I work with have started to call it "Mini-Me" :yepp:Quote:
I love the huge autocascade in the background. "Say hello to my little friend".
Lol cute, you should officialy name it that after it is finalized lol!Quote:
Originally Posted by mytekcontrols
rofl, -100c @ 3600w for the big brother. What is that going to be used for?
Nice work.
polizei:
the large one is a gas chiller ;)
To condense a gas into liquid?
Actually the large one is not a gas chiller, but a direct expansion autocascade just like it's little brother. It is used mainly for what is called cryo-pumping of water vapor in Vacuum Coating Systems. These would be systems used for making CD's, DVD's, Optical coatings on eye glasses, ect.
amazing work. Hope ypu dont leave us....
regards
Thanks Marvin :)Quote:
amazing work. Hope you dont leave us....
Here are some photos I took after trimming the excess foam, punched a hole through the top of sheet metal enclosure, installed a strain relief, fed the line thru it, and seated it in place.
This is a test fit, since I still need to seal the cut foam, and finish some odds and ends. However I am pleased with the results thus far. With a nice front panel, I think this thing will look pretty sweet :up:
Compact!
Nice work! :up: :)
You have the neatest work here, without a doubt, somoene needs to give you a damn award.
that is simply amazing hey, well done :clap:
WHat size compressors are used in each unit??
Thank's Adam :) Although for sheer beauty, LittleDevil has me beat.Quote:
You have the neatest work here, without a doubt, somoene needs to give you a damn award.
I believe it's 1/2 hp, although the LG literature isn't very clear about this. Displacement is 9cc/per revolution.Quote:
WHat size compressors are used in each unit??
I know it seems small, but with 2 HC's as part the charge (R-600, R-170), and based on some other tests I made with R-600, I think it'll do pretty good at -100C. R-600 has a fantastic COP, much better then an equivalent CFC, HCFC, or HFC in the same boiling temperature range. I've seen as much as a 20% improvement in load handling.
Edit: Initial charge will use R-600, R-170, and R-14
Really? I thought with what 3 phase seps you'd be using a mid carrier. Definitly want to see its abilities. Had a small question and possible favor, do you think its possible for you (more mainly the group/company) you work with, to get a small amount of ethylene to try? You might find it a cheaper swap for r14 for many applications, and again have better abilities.
Gotta love butane though. :)
Michael, this unit is so awesome! The work is clean, everything fits together so perfect, I love it in the original case :)
(I am coming her to XS to look if there is a progress with your project every day)
Thats two part liquid polyurethane right? What density?
I think I covered this before :confused: But my mind might be a bit frazzled. Phase separation is not perfect, it isn't likely that all of the R-600 will separate out at the 1st, or that R-170 the 2nd, or all of the R-14 at the 3rd. So having an extra stage will help purify the mix down to the lowest boiling component. Of course I do make a sacrifice in terms of heat load capacity, but I will achieve a colder temperature with the mixture I have chosen. Also the not so perfect phase separation tends to keep the number of different refrigerants required to a minimum, since we end up with pseudo boiling point refrigerants (mixtures) in between the actual pure refrigerants being utilized. This also helps to cover the gaps between said refrigerants.Quote:
Really? I thought with what 3 phase seps you'd be using a mid carrier. Definitly want to see its abilities.
And last, but not least, I might also like to add a bit of either R-50 or Argon to get things a little colder still, and this is really where the extra stage will pay off.
Since our plan is to eventually get away from flammable gases in our charges, this is not a probability. But things change, so who knows perhaps someday I might have some to work with.Quote:
Had a small question and possible favor, do you think its possible for you (more mainly the group/company) you work with, to get a small amount of ethylene to try?
Yes I do :up:Quote:
Gotta love butane though.
Thanks godmod, I appreciate your thoughts :) And yes I am quite happy about being able to squeeze it all in the original case too.Quote:
Michael, this unit is so awesome! The work is clean, everything fits together so perfect, I love it in the original case
Yes it is a 2 part foam from InstaPak (MilSpec spray-in type). I'm not sure what the density is though, never really thought about it to tell the truth.Quote:
Thats two part liquid polyurethane right? What density?
Here's a look at the test set-up, and results obtained in this first run over the weekend.
I will give more details over the next day or so :)
Is that -102.6c? Nicely done. :up:
If you ran it deeper into a vacuum, could you get temps lower at that load? I guess I'm just used to seeing single digit pressures suction side in single stages, 43psi might be normal for an autocascade? :shrug:
I do not post in here a lot, but I just have to say:
Michael, that unit is absolutely stunning, I love your attention to detail.
Bravo :clap: :clap: :clap:
Wow! But your target was more load with this temp, wasn't it?
Good luck for tuning :) !
Awesome unit.
Regards
Woohoo! Nicely done, all out of a single compressor :up: I'm guessing as you do more testing you'll have temps for the various heat exchanger? Curious what sort of temps you are seeing on them all. Beautifully done, I'm jealous to say the least.
That's about normal for an autocascade. Super low compression ratio :cool:Quote:
Originally Posted by Polizei
Yes I could, but only if I went with a larger displacement compressor than what I am using. making the captubes of a smaller flowrate would also yield a lower evaporator pressure, but I would lose out on heat load capacity at the same time.Quote:
Originally Posted by Polizie
Unlike a standard cascade, it is the nature of an autocascade to run positive suction pressures.
Yes, I was hoping to get 200 watts, but physics have stepped in, and limited me to maybe 150 watts at this temp (need a bigger compressor).Quote:
Originally Posted by Moc
Here was my previous estimate:
But I did put in the qualifier at the end, which would put me at -100C under a 150 watt heat load ;)Quote:
Originally Posted by mytekcontrols
And of course to be fair, I do have at least 50 watts of static losses in the line and coil insulation. If better methods of insulating were employed, these losses could be minimized.
Yes I got some stack temps, but not all.Quote:
Originally Posted by gomeler
Here are the specs:
Cool-No-Load Tuned for maximum of 100 watts
- Compressor Pressures: 20/125
- Compressor Discharge: 42.6C
- Compressor Suction: -8.6C
- Strainer#1: -62.6C
- Strainer#2: -77.6C
- Strainer#3: -86.1C
- Strainer#4: -103.2
- Coil Outlet: -115.4C
- Coil Inlet: -116.9C
- Compressor Amperage: 2.2
125 Watts Applied Heat Load
- Compressor Pressures: 43/240
- Compressor Discharge: 51.8C
- Compressor Suction: -2.6C
- Strainer#1: -42.4C
- Strainer#2: -61.2C
- Strainer#3: -67.2C
- Strainer#4: -96.1C
- Coil Outlet: -99.8C
- Coil Inlet: -103.8C
- Compressor Amperage: 3.6
Charge: 7oz of R-600, R-170, R-14 (60%/40% ratio)
The Loaded temps were after adding more R-170 and R-14, in order to take on the extra load. As you can see by looking at the relationship between the final strainer (#4) and the coil outlet; I am nearly flooded.
I would give more specifics on the gas charge, but I had to make so many additions because of inadequate expansion tank volume, that it would be difficult to come up with accurate amounts at this time. I will be increasing my expansion tank size, and recharging from scratch (more test results to come).
It is certainly impressive considering that this is being done with a single 9cc displacement compressor, and drawing just under 4 amps to boot!
Very impressive indeed!
But why the need for a bigger expansiontank? Having high static pressure?
And the temp at the first strainer is really low! Even loaded! Never expected to see that...
And one other thing I noticed... about your HX, you're condensing upwards in your HX. Doesn't seem logical to me :shrug:
I have been inspired :D So it looks like you have a healthy supply of R14 going into the evaporator. When you do your tests would it be possible to load it up to 200-300w? I imagine the temps will drop considerably but would it stabilize with more R-170 mixing into the higher stages?Quote:
Originally Posted by mytekcontrols
Theres the magic ;)Quote:
And the temp at the first strainer is really low! Even loaded! Never expected to see that...
Is he? Never looked, though I've done mine condensing down.Quote:
And one other thing I noticed... about your HX, you're condensing upwards in your HX. Doesn't seem logical to me
Gom, I think he would probably have to shorten captubes a bit more then. As to the high pressures, do you have any room? How about hollowing out the center of the HX foam a bit and adding another one of those expansion tanks.
Yes!!! I need more gas to start with then can be comfortably accommodated in the tank I am using when it warms back up to room temperature. If it gets too high the compressor will have a hard time of starting up, and the motor will draw too many amps, thereby exceeding it's rating.Quote:
Originally Posted by Jack
The velocity of the discharge stream relative to the expansion (suction) stream is much much higher. So there is hardly any chance of liquids being hung up on the up hill discharge circuit, but there would certainly be a potential problem on the suction circuit if it were opposing gravity, such as poor oil return.Quote:
Originally Posted by Jack
No, unfortunately I think anything much past 175 watts would be too much for the little compressor to take. Also I would expect to see the return temperature suddenly heating up to the point where the heat would not be pulled out fast enough before the heater (resistor) would fail. See chart below; which shows the unit before adding extra refrigerant to enable it to take on 125 watt heat load.Quote:
Originally Posted by gomeler
Well very good Mytek.
Would it be possible to get -90C or so for 200W? With that compressor.
Very cool. Thanks for that Mytek, can't wait till you add the larger expansion tanks.
Also what is your static now?
Oh really? Ah well crap, I'm plumbed that way thinking then liquid won't flood back as easily.Quote:
The velocity of the discharge stream relative to the expansion (suction) stream is much much higher. So there is hardly any chance of liquids being hung up on the up hill discharge circuit, but there would certainly be a potential problem on the suction circuit if it were opposing gravity, such as poor oil return.
Fantastic work.
Just a couple of questions:
Firstly how does the efficiency of this autocascade compare to a well build standard cascade, at the same loading / temperature tuning ? (Heat moved Vs Compressor power.)
Secondly, looking at a chart the boiling point for R-600 is -0.4C. Sorry if I've missed this but it's a long thread with a lot of detail - How does this help the autocascade ? Would R-600a not be better, seems as it has the same molecular mass yet has a boiling point of -11.8C ?
-Andrew.
It helps lower pressures ;) and a bunch of other functions. Search for auxillary condenser.
The closest explanation I could find was: http://www.xtremesystems.org/forums/...er#post2110016
I understand that, but how does lower the condenser's temperature ? The R-600 isn't evaporating in the condenser ??
Cheers.
Nah, it condenses very easily and in quantity, this helps give off heat in the condenser, and serves as a big sponge for other refrigerants to seep into.
Sorry if this is going off topic, but seeming as I've done Physics at A Level and I'm still clueless as to why it has this effect, I feelquite dumb at the moment. :P
What I basically don't get, is how it condensing helps remove heat from the rest of the mixture ?
Because it ends up helping move heat down the stages as far as I can see.
I hooked up a standard recovery tank to it before I it shut-down yesterday, and today the static BP = 55 psig.Quote:
Originally Posted by n00b
Edit: My target static BP would probably be to keep it at 125 psig or lower (need to test maximum safe start-up abilities of compressor). So I'll need to calculate the tank requirements based on the present volume (inclusive of the added recovery tank), allowing for a BP at least 2.25 x the current pressure.
I'm not saying that it wont work upside down, but it depends to a large degree on the volume of your suction side, as well as the size of your compressor. However in an ideal design you do want to pay attention to this, especially if you are using your 1st phase separator to do most of your oil return (as I am).Quote:
Originally Posted by n00b
Just like Nol said, it acts like a sponge for other refrigerants to dissolve into. Predominately this would be the R-170 in the system. When this is later evaporated, it'll do so at a temperature somewhere between R-600 and R-170. Think of what happens when you mix refrigerants to create something with a unique boiling point, same as what is done for R-410A a substitute for R-22. It also seems to have the added affect of enhancing the heat exchange in the air cooled condenser, think of it as a liquid heat sink in this case.Quote:
Originally Posted by yngndrw
Edit: It also evaporates within the compressor, pulling heat out as it travels to the condenser.
I think the best way to answer this would be to have some of the standard cascade builders chime in, on how many total compressor amps it would take to duplicate the performance I am seeing with only 3.7 amps. Also I only have 1 fan, whereas a cascade would probably have at least 2 fans (or a single larger one being shared by multiple condensers). the additional or larger fan would also contribute to the amount of amps required to run the system.Quote:
Originally Posted by yngndrw
Yes, if you only use 2 cascade condensers (I'm using 3), increase the captube flows slightly, and charge with less R-14 and more R-170.Quote:
Originally Posted by Nol
Very nice Mytek. That man deserves a DB.:clap:
For comparison, My new cascade atm will do,
100w@-93°C and draw 3.35 Amps (230V = 770w)
150w@-87°C and draw 3.4 Amps (230v = 782w)
Thanks for the info, and I guess I should list mine as:Quote:
Originally Posted by GoD
125w@-102C and draw 3.7 Amps (115V = 425w)
To give a better comparison.
BTW, what is a DB :shrug:
So lets see, if we take an average of pointblanks, call it 125w @ -90C, we can see that Mytek's does -12C better, and draws a bit more then half the energy. Autocascade really is quote amazing isn't it. Whats the max load you can hold though blank? And I'm surprised you don't have much better results coming out of that cascade.
Yep, about 1/2 the energy. I think this gets even better when designing for colder temperatures (-130C to -150C).
I should mention that there was a change in the final captube sizing I used on the AC-2 unit. I made a last minute decision, and increased the flows on the last 3 captubes (decreased length). Here is a chart with what I used:
And here is the heat exchanger info, as well as specs on the 115V LG QA090C rotary compressor I used (notice the rated load current of 5.2 Amps --- I still have some breathing room):
Edit: I gave an average spec on the length of the HXC's. In reality AUX and Cascade #1 were slightly longer, and Cascade #2 and #3 were slightly shorter. Increasing the length of all the heat exchangers would probably yield even better loaded temperatures. Keep in mind that the pressure drop, which is not beneficial, will also increase with added length.
What do you think about plate heat exchangers?
I think they are great, and have better heat transfer then a tube-in-tube design for a given amount of area :up:
And I also think that the AC-2 project would have been significantly easier to fabricate utilizing plate heat exchangers.
Of course Nol you know that already ;)
Hahah yes, any idea to sizing plate wise? I think I need to get some more cash sometime to pickup a window AC, I really like those condensers.
Thanks for explaining about the R-600, I think I get it now. :)
I'm pretty supprised to see how efficient this is - I was expecting to see that cascade compressors would not be strained as hard, hence would draw less.
I'm wondering, why are autocascades so much more efficient ? I'm sure that heat exchanger inefficencies can't loose about 400Watts of energy, so where is it being lost ? (Based upon the comparion statistics that PointBlank God posted.)
Autocascades look like they could replace Single Stages for 24/7 use.
Wish we could pick up window Air Con over here for as cheap as you guys can. :c
Well a large portion of an autocascades high-side is operating at sub-zero temps so the pressures the compressor is fighting against are much lower. The suction pressures are also much higher than traditional single-stage/cascade loops, so the compressor is running in a very happy state. That'll partially explain why it's got such great efficiency. On the other end, you are using the saturation of gases within liquids to help with the temperatures, from my understanding you need specific blends to do this, certain gases just won't get along as well. Oh, did I also mention, hydrocarbons rock? :)
They can replace single stages, most definitly, but costs of parts and gases are higher. Now why are they better off? Often time the compressor is cooled much better, operating pressures can be much lower, and your not trying to cool the next stage down from ambient :)
EDIT:Now not necesarily. From what I've seen almost all the failing autocascades here at XS are only missing the "warm" boiling point refrigerant basically, and often the HX sizes.Quote:
From my understanding you need specific blends to do this, certain gases just won't get along as well. Oh, did I also mention, hydrocarbons rock?
New thought...
I have been pondering why it took so much more refrigerant to get this unit to work than I originally thought. I have been staring at the data collected, and what stands out to me is that that strainer#1 (coming out of the first phase separator) is running colder then expected, and most unusual is that Strainer#2 and #3 tracked pretty close together until I began flooding the final stage. I think I have a plugged captube. And it's either #2 or #3 :rolleyes:
So I'll have to dig into the foam insulation to expose just the captubes, run the unit from a warm start-up, and feel each captube to see if it is flowing (does it freeze water vapor).
If one of them is plugged, then who knows, I might be able to get even more out of the unit.
Ah very true, I guess thats another major problem with this many cap tubes. Have you considered after brazing up all the stages high pressure blasting some compressed air or nitrogen through the highside to remove any problems?
I'd hate to see you dig into that foam :(
LOL! Exactly what I noticed yesterday :D :cool:Quote:
Originally Posted by mytekcontrols
Anyway, not so good news. It looks so perfect right now...Quote:
Originally Posted by Jack
So there could be even more from this unit ? Wow, that's great news.
Michael, if I could request a new experiment for you - Seems as you have an amazing selection of equipment and gasses, as well as you seeming to want to research into the whole autocascade subject. :P
A "drop in replacement" for a single stage. As cheap as possible. (In terms of both gasses and parts.) As small as possible. (Standard single stage case ?) About the same cooling power as an average single stage. More efficient than a single stage.
Think you can do it ? ;) *Crosses fingers*
-Cheeky Andrew.
Heh I don't think thats a fair request!
That's got some serious cash involved.
Well maybe just work out that idea in theory
Or we should set up a fund :D
It's cheeky, so sorry for that. :PQuote:
Originally Posted by n00b 0f l337
But I think it depends upon his situation and how much he wants to research.
Also yes, it could just be calculated in theory.
Was just an idea. :P You don't get anywhere in life if you don't ask questions. ;)
Wow so many questions, and so little time :D
Jack, yep I remember your comment about it being too cold. Probably what got me thinking more. At first I just attributed it to the R-600, which in a previous big unit test, had shown a tendency to make the first stage colder than using R-123 & R-22.
Shouldn't be a problem on keeping the foam looking nice. We do this sort of thing all the time with units that we are repairing. And most of the time the patching comes out pretty clean.
Actually what I should have done is charged the unit before foaming with some nitrogen and R22, ran it, and then checked each captube that it was indeed flowing. Especially with 0.031 ID which are easily blocked when brazing.
yngndrw... A very tiny autocascade (truly a "Mini-Me" unit); someday I just might do something like that, but for now I only have my heart set on completing the present project, and keeping you all informed as to the progress.
My cascade is still in the experimental stage, I was hoping other cascade builders could post some of their results to compare also.
1st stage still isn't as cold as I expected, but those were the figures as of the last time it was run.
@Nol, my load tester only goes as high as 225-230w, but as the cascade stands now, I don't think it could hold much more than that atm. Have a look at my results, she likes 100-150w the way it is, after that temps drops begin to get larger.
Hehe.Quote:
Originally Posted by mytekcontrols
DB is a brand of beer.
Ha found it on youtube
The three guys at the telly are dead NZ icons.
Bloody good ad if you ask me.
If there is dead refrigeration icons looking down on us from cloud 9, they'd be saying the same thing about you mytek.:up:
Thanks for the DB, and yes, that is a funny ad on youtube :D
Well I began digging out the foam on the captube side yesterday evening. Ran the unit, and I think the problem might actually be poor flow on the 1st captube (coming out of Phase Sep #1). It kinda makes sense, since I had to almost double the R-600 to get decent suction cooling (must have flooded over the top of Phase Sep #1).
Recovered the charge, and put it on a vacuum pump. I'll back fill it with nitrogen today, and do some dissection to see what i can find.
Stay tuned for some pics and more info as I proceed.
Oh wow, would not have guessed that. Will a normal vacuum pump get rid of butane? I'd imagine it must if it can get rid of water (dumb question I self answered, I must be out of it!). But are you ducting the fumes out? Whenever I work on a system that I've put propane in I have a piece of vinyl tube over the vacuum pump output to the outside of my workplace.
Good advice, and yes I made sure to do so :)Quote:
Originally Posted by Nol
I checked the #1 captube, and everything looked good, but decided to shorten it to 30" for more flow. It was kinda tricky torching in the foam, but with a carefully positioned wet rag, every thing turned out OK.
I stuffed fiberglass insulation in the hole as a temporary patch until I am sure that I am done with all the modifications (covered with plastic and tape to serve as a vapor barrier).
Test results will be coming very soon.
BTW; the somewhat exposed copper tube to the right is part of the liquid line, and runs at or near room temperature.
Nice job. Do you make your own thermocouples? How are they bonded to the tubes?
Thanks Adam :)Quote:
Originally Posted by Nol
Yes I make my own. Simply twist ends together for about 4-5 turns, pre-tin with 60-40 rosin flux solder, re-dip in flux, use micro torch to pre-tin area on copper with 60-40 solder (flux before hand), while heating --- immerse end of TC in pool of solder, and most important --- hold very steady while it cools.
I was having problems with the R-600. Think it has to do with needing in-between gas such as R-290 (you guys did suggest this earlier).
Anyway for right now I went back to what I am used to working with: HCFC's for Liquid.
Here are the first test run results (No Load estimated as 25 Watts Static):
Here are the Captubes now in use:
Aw dang.
Whats the green hose by the way? Still great results.
The green hose is connected to my addition tank (the small black tank to the left). Presently the other end is not connected to anything. But when I want to add either a gas, or a liquid to my running system, I would connect it to the gauge set and suck it in through the suction side.
Note: The addition tank is made from a suction accumulator, 0-200 psig gauge, 165 psig PRV, and a shut-off valve with 1/4" flare connection. Taking 75 psi from the tank - into the unit - equals approximately a 10 psi rise in the unit's static balance pressure.
BTW; I've had the unit running overnight --- will be doing load tests in a few hours.
Excellent work Michael and damn cold temps for what was at one time an A/C unit :up:
Load numbers are more important :P .
Can you describe the software you use and the controller for 9 probes?
I think it's a load tester that his own company makes, Mytek Controls.
Awsome job re-brasing and not melting the foam and thermocouple cables.
Can't wait to see the load test results. :up:
Thanks Chris. I too am amazed at what this little sub 10cc compressor can do :woot:Quote:
Originally Posted by gomeler
Wait no longer, here they are:Quote:
Originally Posted by yngndrw
Reading the charge from the top of that one table, did you charge 4.5oz of R123, 3.5oz R22, and then whatever PSI you had after that, you added another 85 PSI to that worth of R170 and then another 85 PSI R14? Same for the Argon.
If so, wouldn't that make your static pressures go through the roof?
Opps! Slight error instead of 200 psig, it should have been 215 psig static Balance Pressure.Quote:
Originally Posted by Polizei
Edit: As it turned out, the static balance pressure when warmed-up, ended up being around 202 psig. I figure that at a +20C ambient, we could see as much as 205 psig.
The R123 and R22 liquids will have a combined vapor pressure of approximately 30-33 psig at normal room temperature. No I'm not kidding, the combination of the two liquids results in a vapor pressure less than R22 alone.
Add to this the combined gas pressure of the R170, R14, and Argon (182 psi), and you'll be somewhere between 212 - 215 psig total static BP.
I'll go upload a corrected test chart with the right BP.
Now the interesting part will be to see if the compressor can start-up with this high of a static pressure, without causing the motor to pull too many amps. If it does, I have 2 choices; increase the expansion tank volume, or add a buffer valve w/timer to bypass the compressor discharge into the existing expansion tank. I prefer the later, since it will allow me to keep my package size small.
Different nature of the autocascade beast, I guess. Used to lower statics, like, 100psi, in single stages.
What do you mean you wonder if the compressor can start without drawing too many amps? Haven't you run it already?
:DQuote:
Originally Posted by Polizei
Yes I have run it (how else would I have gotten the data), but the system was originally started up day before yesterday with a lower static BP of 154 psig. I then boosted up its charge while running, in order to tune it for 150 watt operation, and then incrementally reduced the applied load to obtain the load profile curve you saw above.
I shut it down, and watched its pressure build while also observing the temperatures of the stack TC's. When it got to nearly 0C and was just approaching 200 psig, I was satisfied that it was tracking with what I had estimated the additions should increase it by. When I get a chance today, I'll try a re-start and see what happens. I'll also verify what the warmed up BP is as well.
Oh... so you haven't run it since you initially charged it.
I was going to say...
:rolleyes: Yes I have run it. I just haven't re-started it from a warmed up state.Quote:
Originally Posted by Polizei
As I said earlier, I made refrigerant additions while it was running and cold. Just haven't verified how these additions will ultimately add up, or how they will affect the start up capability of the unit.
Edit: I think we are of the same understanding... just saying it in different ways.
Oh. Cut me some slack... I was up early for an extremely boring C++ programming class this morning. ;) :p:
My reading comprehension went back to bed.
OK you win :D But when I turn 70 and the alzheimer's begins to kick in, I'll be expecting the same :rofl:Quote:
Originally Posted by Polizei
Sounds fair. :up:Quote:
Originally Posted by mytekcontrols
He means that he is wondering if the Amps drawn by the compressor at startup will exceed its maximum rating or if it will be within specifications.
This is what I still need to find out. Hopefully it will be within specifications, or can be persuaded to by allowing the discharge to bypass into the expansion tank immediately upon start-up. I figure opening a solenoid valve between the compressor discharge line and the expansion tank for maybe the first few seconds would probably do it.Quote:
Originally Posted by godmod
The LG QA090C's motor current rating is 5.2 amps @ 115V, exceeding this by as much as 1.25% (6.5 amps) for a short period of time should do no harm, and is considered acceptable. Going much over this could cause a premature failure.
So I'll see what happens later today.
Stunning work Michael, top notch stuff. -100 at 25W+ over your initial goal. You must be pretty happy :) :up:
5.2A + 1,25% = 6.5A ?Quote:
Originally Posted by mytekcontrols
Does not work for me :confused:
(It would be 25%)
I am sure he meant 25%, which you would multiply by 1.25 :)
Just a % sign in the way of a perfect calculation :rofl:
You are rightQuote:
Originally Posted by RyderOCZ
...like double negation :)
Yep, I did mean 1.25 x 5.2 amps, or 25% over spec. Sorry :(
(damm... Alzheimer's kicking in already)
Interesting idea, and yes I see how this could work (I'll have to write this down) :comp10:Quote:
Originally Posted by SoddemFX
But not to dismiss it, I will probably do the buffer valve thing I mentioned, for the simple fact that I have used this before in autocascades with great success. Although it does depend on small pressure drop to be effective, where as your idea doesn't.
Yes I am! :party:Quote:
Originally Posted by RyderOCZ
Thanks for the kudos.
Basically the same as an idle load switch in a way. Just a way to connect high and low with little to no restriction. Plumb it into the expansion tank and let the restriction between there and system to equalize and then close the valve once compressors going.
Coil outlet is Evap inlet, in the graph :shrug: Shouldn't it be Evap outlet?Quote:
Originally Posted by mytekcontrols
Anyway 150 Watts! Nice! :D
Not too shabby!
Some thoughts...
I have been doing some thinking on why the R-600, R-170, R-14 charge did not work as expected. It appears to all come down to how effective is the separation in my home brew phase separators. I had assumed it would be simply adequate, but not phenomenal, especially in the later stages. But now I'm not too sure about this.
Remember the 3600 Watt "Big Brother" unit I showed in a previous photo? A unit similar to this was my first test bed for an R-600 charge. It worked unbelievably better, and with only half the liquid (R-600) than the previous R123/R22 combo. So I just assumed that I would see similar results with my AC-2 unit when using R-600. Why didn't I? well I think that proportionally speaking, all my phase separators are much much larger then what is used on the "Big Brother" unit. How much larger? At least 13 times the volume (based on compressor mass flow differences).
So it would stand to reason that the AC-2 unit would be far superior in its ability to separate the liquids from the gases at each phase separation point. Having poor phase separation allowed the "Big Brother" unit to get by without a mid-carrier refrigerant between R-600 and R-170 (80 degree C difference in boiling points).
But the AC-2 unit with its superior phase separation, ended up disconnecting between the lower and upper stages, mainly due to excessive amounts of R-170 being dissolved into the R-600 and robbed from the downstream stages. And later as the lower stage got even colder due to it's isolation from upper stage loads, the temperature dropped to the level that even R-14 was being gobbled up as well. Probably the best way to over come this would have been to add a mid-carrier refrigerant such as R-290 or R-22. Another way was by using brute force, and adding excessive amounts of R-170 and R-14 in order to compensate (this is what I did on my first tests). But from a thermodynamic aspect, this probably just ends up making 3 phase separated autocascade, into something that acts more like 2 phase separated design due to inter-stage flooding.
R-600 should still be better at moving heat then an HCFC. So perhaps I'll try a future test with an R-600/R-22 combination to see what happens. If I had R-290 I'd try that as well.
I still might get even more out of the AC-2 unit :yepp:
Yes you are right :shakes: It's now fixed :)Quote:
Originally Posted by Jack
Thanks Jack ;)
Adam... Yep you got it!Quote:
Originally Posted by Nol
R290 is insanely easy to get in decently high purity. Hop to homedepot, blue bottles from bernzomatic, like $2 a pop. Then pickup a $10 propane soldering/brazing torch, cut off the end of the torch, and braze an access valve to the bottle attachment side. Tada R290 ;)
Great idea! And so simple.Quote:
Originally Posted by Nol
How pure do you think it is?
I know that with huge ammonia chillers they use pretty much the same thing.Quote:
Originally Posted by mytekcontrols
There's a pipe going from the the top of oil separator the the suctionline, just before the compressor. That pipe has a valve which opens for 1,5 minutes after start-up. After the 1,5 minutes the compressor has reached enough rpm to overcome the static charge.
Technical Propane has got a purity of 95%.
The 5% are unknown, other HCs, Water.
I can tell you for Propane 2.5:
Purity 99.5%
O2 max. 100 vpm
CO + CO2 max. 10 vpm
H2O max. 12 vpm
KW C1,C2,C4 max. 0,7 Vol%
Bernzomatic is 97.5% according to them, other stuff is HC's and air in small quantities. Run through a filter on the way in. I use that and its more then pure enough to run full singles and cascades on 290 only.
Quote:
Originally Posted by n00b 0f l337
How about a explanation of the law in the USA of using propane in refrigeration systems..........or pure HC's. It's actually illegal to modify(say a torch) to use it other than for it's intended purpose.
Are refrigeration units being designed/built to satisfy all the regulatory bodies,Or are potential bombs being built. :shrug:
Even systems designed with every safety precaution possible/thinkable occasionally things still go boom "$hit happens" doesn't get you a "Get out of jail free card".
I don't know......... :shrug: Once you start selling/shipping units you just opened yourself up to exposure from all government regulations.
What do you guy's Think ??????
I never sell units charged with propane Walt. Don't be jabbing at me. What do you think ethylene is? And no its not illegal to modify tools for other purposes. And from tests, and after seeing window ac's explode (see thread still available to read in first two pages here in vapor phase forum), impinged and "atomized" oil in refrigerants is much more deadly.
And what about hydrocarbons in other refrigerants? Many have r290 in them. And autocascades, mytek would you like to explain the legality of using butane? I don't see a problem.