Evaluate my plan for the phase change setup

[hydrogen18]

goal

- Will be used to chill water(with additives to lower freezing point, like windshield washer fluid and antifreeze) for a watercooling setup

the parts

- Whirlpool dual loop? i think(it has 4 pipes on it, 2 copper, 2 steel) 1/4 HP compressor never used. Drained lots of fluid out of it(oily).

- Im going to use coils of copper pipe for the condensor and evaporator. Each will be inclosed in PVC pipe, which will be sealed. The pipes of the evaporator/condensor will be routed out through holes in the side(which will be sealed with epoxy). Barbs will also be in place, which will allow water to circulate through it all. This means water will take heat away from the condensor, and water passed over the evaporator will be cooled.

- Water to cool the condensor will be brought cooled by a bong.

- need thick walled tubing with small ID for cap tube

what i need to know.

- Why the F*** are there 2 steel pipes and 2 copper pipes on my compressor? is it a dual loop(one for fridge, one for freezer?)or something else?

- Length of capillary tube and ID

- What refrigerant and how to put it in the system(needed valves etc). I am thinking propane. A pound costs around around $2 here. In addition the valve for my torch head, uses a flare fitting, so it should be easy to connect to copper pipe fo r putting into the loop.

- What oil to use. Putting it in the system should be fairly simple. I just need to know where to get it, and how much to put in, and what kind it needs to be.

- How to prevent refrigerant from stagnating(pooling up) in the loop.

- Do i have to use a vacuum pump? i dont need the absolute lowest tempatures since too low would freeze the liquid im trying to cool.

- How to cycle the compressor to prevent freezing my liquid(and extend the life of the compressor).

thnx...

[8-Ball]

I see you took my advice.

You should be able to get some useful information here.

8-ball

[Brians256]

Wow. I don't think you know what you are letting yourself into. Phase change cooling requires a bit more research than I think you've put into this (so far). Believe me, I'm going to do my best, but what you really seem to need is a crash course on phase change cooling in general and HVAC repair in particular.

Let's start with the first problem. How can anyone help you if you don't say what the model number is for your compressor? Second, I doubt it's double loop. You might have two extra tubes (one on inlet and one on outlet) for monitoring and fill points. Someone else (hopefully) knows more about that than I do. But, the best place to get info on your compressor is from the manufacturer.

Second, did you know that the oily fluid you drained out was supposed to be there? It might be POE or it might be mineral oil depending upon whether the compressor was designed for newer (non-CFC) gases or if it was designed for the good old R-12 or R-22 style gases. If you decide to go with propane, you should use mineral oil, and if you go with R-134a, you should use a POE type lubricant. Did you know that you have to clean out your compressor if it was using the other lubricant? Did you know that compressors are designed for one particular gas (they might be able to use others at a reduced efficiency though)?

Do you know how to calculate the required cap tube size? Do you have a set of gauges? If they've ever been used with R-12 systems, make sure you don't use them in a newer system like R-134a because of the minute presence of mineral oil which can damage newer systems.

Preventing "stagnation" is important, true. However, the primary problem is the LUBRICANT, not the refrigerant. If you don't get the lubricant (which is dissolved in the refrigerant) back to the compressor, you can expect a smoking compressor real soon. Basically, use common sense. Depend upon the fact that liquids fall "faster" than gasses, and that the lubricant will move best with gravity instead of against it. Look at typical refrigerator/freezer designs. Do they have the compressed gas going into the TOP of the condensor or the bottom? After the phase change is complete, don't worry. Everything will get pushed. It's where the phase changes happen that you need to worry. Look up things like "accumulator bulb" and "flooded evaporator" using your favorite search engine.

I recommend propane because of it's cost per unit of performance. Unless you have a source for the more exotic refrigerants, it's hard to beat propane. Some people are concerned because propane is flammable, but just be careful. You'll only be using 2-6 ounces anyway (unless you have a really large or just badly designed system).

Yes, you'll need a vacuum pump. If you leave water in the system (by not evacuating it), you will be very likely to burn up your system. Water has a habit of eating up compressors because it interacts with the lubricants and the refrigerant to form hydrofloric acid. Also, even if you don't think it will get that cold, water can very easily plug up your capillary tube.

How do you control your compressor? Use a thermocouple to sense temp, and make it bistable so that it comes on at a higher temp than it turns off (otherwise it will flutter around the turnon/turnoff temp).

Have you read the ProCooling article on phase change? Please do here. It has a lot of basic theory that should help ya.

[hydrogen18]

Wow. I don't think you know what you are letting yourself into. Phase change cooling requires a bit more research than I think you've put into this (so far). Believe me, I'm going to do my best, but what you really seem to need is a crash course on phase change cooling in general and HVAC repair in particular.

- I do have an idea of what I'm letting myself into, but not enough to completely build the system. Hence the reason Im posting here.

Let's start with the first problem. How can anyone help you if you don't say what the model number is for your compressor?

- Ive googled for the model number before and got nothing. Ill get a picture and the model number soon.

Second, I doubt it's double loop. You might have two extra tubes (one on inlet and one on outlet) for monitoring and fill points. Someone else (hopefully) knows more about that than I do. But, the best place to get info on your compressor is from the manufacturer.

- I havent tried contacting whirlpool, I guess i need to do that.

Second, did you know that the oily fluid you drained out was supposed to be there?

- I was concerned a lot of it could be condensation, which i figured could cause rust. Therefor I tilted it on its side till most of it came out.

It might be POE or it might be mineral oil depending upon whether the compressor was designed for newer (non-CFC) gases or if it was designed for the good old R-12 or R-22 style gases. If you decide to go with propane, you should use mineral oil, and if you go with R-134a, you should use a POE type lubricant.

- I'm pretty sure its not R134a designed, as its an older compresoor(Though it was never used, and has the original pipe plugs in it). Chances are, it was mineral oil and potentially condensation like i said.

Did you know that you have to clean out your compressor if it was using the other lubricant? Did you know that compressors are designed for one particular gas (they might be able to use others at a reduced efficiency though)?

- Yes, I know i must clean it. Since I am un aware out what fluids where in the compressor, I figured I should flush it thouroughly and start from scratch. Yes I know compressors are designed for one gas. I am prepared to take a drop in effeciency by using r290.

Do you know how to calculate the required cap tube size?

- No. I know it is dependent on refridgerant, but is it dependent on compressor model/power also?

Do you have a set of gauges? If they've ever been used with R-12 systems, make sure you don't use them in a newer system like R-134a because of the minute presence of mineral oil which can damage newer systems.

- No, I'm hopinh my uncle(a refridgeration specialist) can give me some help in filling the system. He has the appropriate gauges I beleive.

Preventing "stagnation" is important, true. However, the primary problem is the LUBRICANT, not the refrigerant. If you don't get the lubricant (which is dissolved in the refrigerant) back to the compressor, you can expect a smoking compressor real soon. Basically, use common sense. Depend upon the fact that liquids fall "faster" than gasses, and that the lubricant will move best with gravity instead of against it. Look at typical refrigerator/freezer designs. Do they have the compressed gas going into the TOP of the condensor or the bottom? After the phase change is complete, don't worry. Everything will get pushed. It's where the phase changes happen that you need to worry. Look up things like "accumulator bulb" and "flooded evaporator" using your favorite search engine.

- Will do.

I recommend propane because of it's cost per unit of performance. Unless you have a source for the more exotic refrigerants, it's hard to beat propane. Some people are concerned because propane is flammable, but just be careful. You'll only be using 2-6 ounces anyway (unless you have a really large or just badly designed system).

- Thats good to hear.

Yes, you'll need a vacuum pump. If you leave water in the system (by not evacuating it), you will be very likely to burn up your system. Water has a habit of eating up compressors because it interacts with the lubricants and the refrigerant to form hydrofloric acid. Also, even if you don't think it will get that cold, water can very easily plug up your capillary tube.

- As long as no water was in the system when I assembled it, and if I fill it prior to a rapid change in tempature(causing condensation) I should be able to avoid water in the system I thought? Can I use an old compressor as a vacuum pump? My uncle may have a vacuum pump.

How do you control your compressor? Use a thermocouple to sense temp, and make it bistable so that it comes on at a higher temp than it turns off (otherwise it will flutter around the turnon/turnoff temp).

- The compressor has no present control system.

[hydrogen18]

The compressor.



The metal label on top of the compressor.

it reads:

V115 Hz60 V100 Hz50
PHI LRA Z3 A 7 82 E
<big print>462546</big print>
Thermally protected whirlpool

i know the top line is voltage ratings(im guessing this compressor has 2 voltage supplies, hence the 3 power connectors.). The bottom line is self explanatory. Any idea on the middle 2?



The ?power? connector for the compressor?



3 of the tubes on the compressor. The upper 2 shown here are the steel ones. The lower 1 is one of the copper tubes.



The other copper tube. Why the funny ridging on the tube?

Another Q:

- Can I use copper pipe I get from Lowes or Home depot as the piping(Except for the cap tube) for my system?

[Brians256]

I think you should wait until you have good info from the compressor manufacturer before you go any further. That will determine a lot of what you'll do.

[hydrogen18]

where can I find info on my compressor? Is there some database I could sift through? whirlpool doesnt actually sell there compressors outright, so not much luck there.

[Brians256]

Whirlpool should have manuals available to technicians who repair their systems. Talk to your local friendly HVAC repairman. You would want to do that anyway, since that person will be able to help you do things like properly charge your system and help you decipher the cap tube tables that the mfg's put out.

Hint: try making friends with the repairmen at a business that caters to commercial clients. Residential repairmen don't exist anymore for all practical purpose. Only commercial sites repair their HVAC systems anymore, because it costs more to repair a home fridge/freezer than it does to replace it!

I'm not trying to avoid answering your questions, but you really need a set of specs before you design, imho.

You can just forge ahead and blow it out with dry propane and stick mineral oil in there, and then hope that a dryer will get the rest of the moisture. You can cut different lengths of cap tube and do the try-try-again approach too. Experimentation will lead you to the proper restriction length. Or, you can stick a thermal expansion valve on the system to replace the need for a cap tube.

But, I suggest that you try to determine what you've got first and then you can start calculating a good starting value. For example, you don't know how much pressure differential the compressor will support, nor do you know the maximum flow rate that it will push.

Oh, as for valves, I suggest going to Graingers (they are on the web) and get some schrader valves. Adding access points at several points along the loop will really help you fine tune your system.

[aenigma]

If you decide to go with propane, you should use mineral oil, and if you go with R-134a, you should use a POE type lubricant. Did you know that you have to clean out your compressor if it was using the other lubricant? Did you know that compressors are designed for one particular gas (they might be able to use others at a reduced efficiency though)?

Did you know propane is compatible with all oils and there is no need to change oils?
did you know using propane will increase the performance of the system in this case?

Do you know how to calculate the required cap tube size? Do you have a set of gauges? If they've ever been used with R-12 systems, make sure you don't use them in a newer system like R-134a because of the minute presence of mineral oil which can damage newer systems.

The correct size is usually around 6 feet of .026".
Did you know minute ammounts of POE will not cause acid when mixed with mineral oil?If you have significant ammounts of oil mixed, then you can get problems like waxing.Don't want that.

You won't find any info on that compressor, unless you wan't to do alot of hunting.
You also don't need to know all the information.

hydrogen18:
Go ahead and contact me, I will help you with your system.

[Brians256]

Thank you aenigma. Please continue to post here so that others can share! There's no need to get snooty. If you thought I was, then please re-interpret. I was merely concerned that Hydrogen18 was preparing to start without being aware of the possible dangers. That's why I specifically said, that he can just forge ahead with some guesswork values while blowing things out with some dry propane.

Yes, I know that propane is better than R134a.
Yes, I know that propane is compatible with both mineral oil and POE.

Yes, propane is compatible with both lubricants, but I was referring to the need to flush the compressor. If he sticks with mineral oil, he has no need to clean out the compressor to switch over to POE.

As for wax buildup, YOU ARE CORRECT, so thanks for the better info. I heard it was acid formation, from cross contamination, not wax buildup, but that is wrong info. You and bowman (for example) are far more knowledgeable about HVAC than I am. I'm not trying to discourage anyone from experimentation, but I do encourage people to really know what they are doing before they burn up or otherwise damage their compressor. Cross contamination is such a danger. So is insufficient capillary tube length, water contamination, etc...

The purpose of my questions was to encourage hydrogen18 to do some research and reading, not to irritate him. You and bowman know far more than I do about HVAC, so no argument there. But, unless you get to a certain point, trying to start an HVAC system will be more frustration than joy.

Now, for a more enjoyable topic, a technical question for aenigma, if he is willing to answer.

Why would it be 6'? Is that based upon the 1/4hp figure? I thought it was compressor specific, since it would depend upon the pressure differential as well as the flow rate curve from the compressor. This is why I suggested looking up figures from the mfg. I thought you would also would need to figure in the heatload to make sure you were not going to send liquid back to the compressor while making sure that as much as possible of the evaporator is flooded. Anyway, the rule of thumb I saw on www.rparts.com was for about 50"-55", but that may be for a heavier load than a CPU would create.

Anyway, I hope we can keep the conversation positive while not encouraging people to burn up their equipment (which is what I was trying to do).

[hydrogen18]

more Qs...

- How do I flush a compressor? pump water through it?

- I know there is special mineral oil for refrigertation...but can I use the stuff you buy at walmart for a few dollars a bottle?

ok...

As for the cap tube, I may invest in an expansion valve(or just try a cheap plumbing one from the hardware store first) so it may be non existent( i know there are variables for expansion valves also, but it should help a small amount).

Im thinkinh about trying to find a small mini fridge or old de humidifier for cheap, and ripping a small compressor from it. There are 2 old fridges dumped in the woods near my house I may try and cut the compressors from. This 1/4 HP compressor cost me only $20, and i probaly wont get one so cheap again any time soon.


ill will definetly continue to post here...


EDIT:

- that 3 pin connector for power seems to be pretty standard...anyone wanna post up a schematic for it?

[Brians256]

Flush the compressor by running dry air through it. Preferably dry nitrogen. But, some people run dry propane through it if they have a bunch of it laying around. Really, though, I prefer using a vacuum pump. Please try to never put any water at all into your compressor.

I do not know if you can use the standard mineral oil from walmart. It might be high enough purity. Anyone know that one?

I don't think a plumbing fixture will work with the high pressure in an HVAC system. If you are low on funds, a cap tube will get you started and then you can try a thermal expansion valve later on if you want to have optimum performance over a range of heat loads (i.e. being able to dump more refrigerant into the evaporator when the system is fully loaded versus throttling back when the CPU is idle so that you don't get liquid slugging). I think that 6' is a good guess, but it depends upon how well you insulate your system, and upon your evaporator design, etc... Many people have said that 6' is a good starting point.


I believe that the three pin power connector is standard AC wiring: hot, neutral and ground. Perhaps someone else knows for certain.

[hydrogen18]

Flush the compressor by running dry air through it. Preferably dry nitrogen. But, some people run dry propane through it if they have a bunch of it laying around. Really, though, I prefer using a vacuum pump. Please try to never put any water at all into your compressor.

- Ok, ill hook up a bike tire compressor somehow i think and leave that running a while?

I do not know if you can use the standard mineral oil from walmart. It might be high enough purity. Anyone know that one?

- A book I read said I needed refrigeration mineral oil, but standard mineral oil could easily work i think.

I believe that the three pin power connector is standard AC wiring: hot, neutral and ground. Perhaps someone else knows for certain.

- I know that, but on the connector on the side of my compressor, which one is hot, neutral, and ground?

[Brians256]

Bike tire compressor is not going to give you dry air. It just pumps normal air at higher pressure.

As I said about the other two, I don't know for sure. I would bet that bowman, aenigma or one of the other phase change would know, though.

[Joe]

Originally posted by aenigma
hydrogen18:
Go ahead and contact me, I will help you with your system.

Umm I think everyone can appreciate people helping others, but its very counter productive to take a thread that could get better with some more info and just tell someone to email you.

Since you obviously feel that you could help him, why not post it for others to share also?

This line

"You also don't need to know all the information."

is priceless... hehehe I love it when people tell others they dont need to know something.

[hydrogen18]

spent 1.5 hours cutting this beast out of a fridge 2day...




Ok, the compressor. WTF is that big U shaped thing?



Whuts this doohickey? a fill point?



I kinda cut one of the tubes trying to get it out...thought it wasnt important...seems to be linked to the system...guess i seal it with epoxy.



Leaking loads of oil. At least 1/2 a cup has came out by now. Messy stuff.

Havent tried to fire it up yet...still dont know where to apply power to the pins.. I ohm metered the pins on the power connector and each one is connected to every other one.

[aenigma]

Joe:
Well, considering no one ever posts here, what is the point of that?I also find it much easier to help someone when they ask me one question at a time.

You didn't understand what I meant when I said you don't need to know everything.It helps yes, but good luck finding all of that information, because you won't.I would love to have a sure fire way of making a system, but the sad truth is it takes alot of educated guesses.

Brians256:
Sorry, it sounded like you were just ribbing on him
The capillary length was just an estimate.Alot of people use around that length.I used about 5-6 feet and got nice temps, then just as a test I used 10 feet and got worse temps.
A program to calculate capillary length would be very nice.

Yeah rparts lists capillary size just for freezers or things like that.Cpu's don't put out much heat.Which is why TXV's don't work well, the smallest one is meant for about 300 watts I believe.

hydrogen:
No an air compressor will just pump air through it.There is no need to flush your compressor if your putting the same kind of oil back in.

Use refrigeration oil, I wouldn't risk being cheap.I believe refrigeration oil is meant to work at a wide range of temperatures.

The poles on your compressor are start run and common.You need to get a capacitor for it and find a schematic of the compressor.

That is one odd compressor, I don't know anything about those really.I have seen alot of them, but never "examined" one.Looks like your better of just using it as a vacuum pump and getting a good compressor for your phase change system.

<edit>
Oh look I got an immature custom title.
Thanks a bunch fellow!

[Brians256]

I will try to change the "custom" title, aenigma, but I don't have permissions to do that, and Joe is cut off from the net tonight because of his local cable company's mistake.

As for the bitter attitude about "nobody posting here", I would prefer that to change that. Any suggestions on how to have more people contribute to benefit all of us? Yes, I know that there are people posting on your forum, but I'm specifically interested in seeing how we can improve this site since I'm already here.

[aenigma]

I don't know why nobody posts here, this is a popular place.Just the phase change section seems to be pretty dead.

By saying my forums I assume you mean phase-change.com.I am just a mod there, fredperry is the admin.

When I siad nobody posted here I didn't have a bitter attitude.Just pointing out that no one is ever in this section.
The other areas of proforums are pretty active aren't they?I only check the phase change sections of forums, so I don't know if the other sections are active or not.

[g.l.amour]

if someone can delete this post in a while because it is not relevant...

for the sake of the discussion. i am quite enjoying this thread, but since i know next to nothing about the subject i don't post. it would be nice for this thread to turn out to something like bowman's thread. if i can read up enough about it, who knows, maybe one day i might take the plunge.

plz, keep up the discussion , it is not in vain.

cheers

[hydrogen18]

you people dont seem to care enough about this project anyways, and i have no where else to go...so im calling it off

[Brians256]

That's really sad, hydrogen18. To say we don't care is odd, when I've spent quite a bit of time trying to answer your questions already, and so has aenigma. If you sense any reluctance from me, it is that you may not have enough background to not damage the equipment you have salvaged. Yet. Keep going!

However, if it's too hard for you, I can understand that. Phase change really does require a hefty time commitment. This is not a project where we can just say, do this and that and it will all turn out great.

If it's because we haven't answered all your questions... well, I don't know all the answers. Mineral oil: I don't know if Walmart's stuff will work (I suspect not). The compressor plug: I don't know, and the best answer is the manufacturer or an HVAC tech (which I don't think you've contacted yet as I suggested). The odd-shaped compressors: I have never used those models. You've asked several questions that I don't have answers for, and I haven't responded because, frankly, I don't know.

Anyway, don't give up because you don't think people aren't helping YOU enough. Some of this info has do be dug up by your own efforts.

[hydrogen18]

i gave up b/c it looked like you spent more time arguing over who was better than actually trying to form a constructive answer. Not due to time constraints or anything like that.

[Puzzdre]

Just my .02:

The phase change is complex subject. Much more than plain wc'ing (I'm referring to the fact that even technically challenged can buy industrial parts and make wc'ed rig in short time, just reading the instructions and following the common sense, not the complexity of making the wc'ed system effective). The phase change is not like that. Too many variables, different mediums (and more dangerous too) to work with.

What I'm trying to say is, there are many of us reading and LEARNING from you guys who know what y're doing. Be sure that if I (or better, when I) decide that I learned enough to TRY to make the phase change system (not just rip the fridge and try to bend the tubes to fit the smaller case ), I'll post questions and ask for more. But now, I'm learning. And keeping quiet. And I'm sure there's lot's of ppl doing the same.

Pls, dont stop.


Hydrogen18, I'd like to be in your shoes, to actually try to make the phase system. Somebody must be the first, and for us others (future noobs in pchange), to serve as a good (or bad ) example what to do and what not. There's no real reason to give up, on your project, and on us.

Keep on, we're watching!!!

PS, sorry, this is somewhat more than .02, but I sorta got carried away...

PPS, I actually junked two deep freeze boxes a year ago, and didn't even care to have a look of the components...Now I wish I have them back. Think that now I would junk them, but with scalpel...that way I would have them for a long time...

/edit: seems like I just cannot stop,
another reason why I like it here, written, I can read and re-read it as many times as necessary to have it settled in my mind. Ofcourse, I can always go and talk to the 'friendly' HVAC technician, but I cannot know how much he really does know about the thing, and second, I cannot re-read that, and we all know how people act funny when they are in front of the camera ...and I even don't have the video camcorder...and I cannot ask him to be my roommate for a month or two...

Duh, enough, my brain hurts...gotta have some sleep!

Cheers!

[Enyin]

Hi Hydrogen 18,

Don't give up sir! Just looking at the views on this thread you can see that lots of people are interested in your plan - the fact is we all probably have our own plan but are struggling with some of the same questions as you.

Especially when it comes to sizing condensers, evaporators and cap tubes you will probably not be able to do the calculations to do it the technically correct way - I've spoken with the 'friendly HVAC technician' they generally just repair systems and haven't done this stuff since they took classes 15 years ago - the systems they put together have parts specified by the manufacturer, they don't normally do what we're doing and are *usually* not engineers with the capability of designing systems from scratch

If you really want to get into the calculations take a look at this guy's site, he's seriously hardcore:
http://home.attbi.com/~prithabrownin.../chiller1.html
q= Usystem x Aheat exchanger x ÄTlog mean = OMG

I have not seen one computer related phase change site / project that documents the calculations on sizing these parts - it really comes down to some guesswork - try rparts.com for cap tube sizing, they have a decent chart.

Also put a sight glass before your cap tube so you can make sure you're getting 100% liquid from your condenser, and put another sight glass before the suction inlet on your compressor so you can make sure you're not getting liquid into the compressor. Once you've done that you can adjust the other parts till you get what you want. Soft copper tubing = Mucho Cheap!!