-Chiller Project-

[Pf.Farnsworth]

I have a few questions. I was thinking about getting an ac unit and making a chiller. The desired temperature under no load is -50C. I wanted to ask you guys for a recomendation on which ac unit I should buy that would be capable of that. I am guessting something arounf 7000-8000 btu's? I am familiar with phase change but its always been in classes and theory and from reading these and other boards for a few years now. I have no hands on expirience, so I want to start small and work my way up. Any sugestions on a unit guys?

I have also been wondering what size condencer should one get if one wants a pasive set up with no fans on it. Provided its possible at all. I guess the first question that pops up in my head is how much heat lets say a 6000btu compresor would put out, then I would look for something for the condencer that can passivly disperce that heat. Am I on the right track guys?

Another thought that occured to me is Oh-Oh factor. I am thinking of having 2 pumps in case one fails. But having 2 compressors in case one fails is not very practical so I was thinking about making a fairly simple relay that could cut the power to my computer if the temperatures would go over a given limit. I would hate to loose a $1500 prosessor and 2 $500 video cards lol. Any advice on that?

I also had a question about insulation. I realize that the cold will spread though the board so the area around the socket (even if the socket in insulated) can drop below ambient causing condensation. My question is how far from the socket should I insulate taking in to consideration temperatures of -40C to -50C?

Question about a pump. What would be a good pump to use for this. I am looking for something with good flow rate but something reletivly quiet. It needs to handle temperatures as low as -50C and I am guessing, and hear that some would crack so one needs to pick carefully. Any recomendations?

I was wondering about using a water block for an evaporator, how do blocks with plexi glass / derlin tops handle temperetures of -50C and the preasures of phase change? I am thinking it wont cut it but I thought I'd ask anyway.

I guess this one goes along the lines of the previous question, but how does the plastic tubing we all use for water cooling handle temperetures of -50C? If my coolant will be around those temperatures do I need to consider other options for coolant lines? If so what works?

Last question lol, when brazing copper I know that if you go above a sertain temperature (I think its 1500F but I am not sure *propane tourch temps I think) then the copper changes in composition, bacomming soft and malueble. Obviously this is not good, and what the copper pipes I have seen in my house water system, they all look nice and shiny and hard. So I am guessing you have to stick to a sertain temperature not to mess it up.

Thanks in advance guys, I will be posing lots of pictures as soon as I will start the project. Some things are already in the mail, and alot are a trip to Home Depo away

 

[Bob Vila]

Neither water blocks and their plastic tubing can take the extremes in pressure and temperature that a phase-change system will put on them.

For reference, you are making a phase-change system, correct? "Chiller" leads me to believe you are builing a water chiller. If that's true, you wont get -50c.

In the beginning, you might want to try building a water chiller out of an A/C unit. And after you've fiddled with that for a month; you could take the same A/C unit and make it into a phase-changer.

Personally, I'm doing a water chiller first. Here in a college town (central Illinois), there are always students coming and going that have freebee window A/C units or window A/C units on the cheap. Big plus about using an window A/C as a water chiller, you don't have to invest in all the equipement required to make a proper phase-change system.

I'm trying to get someone to sell me there 10000 BTU window unit for $30. They've been trying to sell it for $100, come winter time they will reconsider it.

 

[9mmCensor]

I would try to find a cheap second hand window AC unit, that way if it gets busted your not boned.

Second is redundancy on compressors and pumps is not needed, because modern CPUs dont overheat and die, they overheat and scale down or shut off.

 

[sandman001]

Neither water blocks and their plastic tubing can take the extremes in pressure and temperature that a phase-change system will put on them.

For reference, you are making a phase-change system, correct? "Chiller" leads me to believe you are builing a water chiller. If that's true, you wont get -50c.

In the beginning, you might want to try building a water chiller out of an A/C unit. And after you've fiddled with that for a month; you could take the same A/C unit and make it into a phase-changer.

Personally, I'm doing a water chiller first. Here in a college town (central Illinois), there are always students coming and going that have freebee window A/C units or window A/C units on the cheap. Big plus about using an window A/C as a water chiller, you don't have to invest in all the equipement required to make a proper phase-change system.

I'm trying to get someone to sell me there 10000 BTU window unit for $30. They've been trying to sell it for $100, come winter time they will reconsider it.

A water chiller is phase-change.

You won't get -50C out of the stock charge on the A/C, simple because of the refrigerant and pressures it will be running.

If you adjust the cap-tube and refrigerant charge, -50C unloaded is doable.

A 5000BTU unit is big enough to cool your computer to -50C.

 

[Pf.Farnsworth]

thanks

Yes I am making a chiller not a direct dye.

No I never intended to use plastic tubing for the phase change side of it. I want to know it it can withstand the coolant (denaturated alcohol) at -50C.

I only want coolant at -50C under no load.


-------------------------

Questions still standing:


-I realize that the cold will spread though the board so the area around the socket (even if the socket in insulated) can drop below ambient causing condensation. My question is how far from the socket should I insulate taking in to consideration temperatures of -40C to -50C?

-What would be a good pump to use for this. I am looking for something with good flow rate but nothing that would be to loud. It needs to handle temperatures as low as -50C and I am guessing, and hear that some would crack so one needs to pick carefully. Any recomendations?

-Will plastic lines and or waterblock with a plastic/derlin top handle coolant temperatures of -50C?

-When brazing copper whats the temperature that should not be exceeded in order to not change the physical composition of copper to the softer and malueble form it takes if exposed to a temperature over a sertain limit?

-So there is no chance of a FX overclocked to the limit dying from over heating, it will be fast enough to shut itself down before any damage is done? What about video cards, how do gpu's behave in a simmilar senario?

 

[Bob Vila]

I only want coolant at -50C under no load.

Wont happen unless you do the the following which was stated above, "If you adjust the cap-tube and refrigerant charge, -50C unloaded is doable." And that's with a direct die. To chill down to -50C with a big ol' evaporator a window unit has, I'm thinking multiple-staged auto-cascade. Certainly worthy of the extreme badge.

Most people who use window A/C units as water chillers maybe get into the negatives with no load. Since you are talking about chilling your cpu and video cards, I doubt you'll keep load temps under 20C.

 

[JoT]

Wont happen unless you do the the following which was stated above, "If you adjust the cap-tube and refrigerant charge, -50C unloaded is doable." And that's with a direct die. To chill down to -50C with a big ol' evaporator a window unit has, I'm thinking multiple-staged auto-cascade. Certainly worthy of the extreme badge.

Most people who use window A/C units as water chillers maybe get into the negatives with no load. Since you are talking about chilling your cpu and video cards, I doubt you'll keep load temps under 20C.

Actually, Sandman was referring to chillers when he said that. My chiller hits -35C under load, if I remember correctly

 

[Bob Vila]

Actually, Sandman was referring to chillers when he said that. My chiller hits -35C under load, if I remember correctly

Really? Wow, I guess my friend is doing something wrong.

How did you submerge your evaporator?

How many things are you cooling?

 

[JoT]

You can PM Sandman there more specific questions, he built it for me It's not a normal A/C chiller.

 

[Pf.Farnsworth]

Vlad on XtremeSystems forums has his coolant at -43C using a window AC unit, 6000 btu's I belive.

 

[9mmCensor]

Vlad on XtremeSystems forums has his coolant at -43C using a window AC unit, 6000 btu's I belive.

Coolant temps, and CPU temps are very very different.

 

[sandman001]

Really? Wow, I guess my friend is doing something wrong.

How did you submerge your evaporator?

How many things are you cooling?

it's a tube in tube design, using a 3/4" corrugated copper liine inside of a 1" copper pipe.

The 1" pipe is the evaporator.

It was load tested using a 320watt pelt at around 14V with a heatsink on the cold side.

 

[sandman001]

Wont happen unless you do the the following which was stated above, "If you adjust the cap-tube and refrigerant charge, -50C unloaded is doable." And that's with a direct die. To chill down to -50C with a big ol' evaporator a window unit has, I'm thinking multiple-staged auto-cascade. Certainly worthy of the extreme badge.

Most people who use window A/C units as water chillers maybe get into the negatives with no load. Since you are talking about chilling your cpu and video cards, I doubt you'll keep load temps under 20C.

actually with the heatload I specified it was like -37C, before I adjusted the cap-tube it was -35C.

 

[JoT]

Ehehehehe

 

[Pf.Farnsworth]

Coolant temps, and CPU temps are very very different.

I think I mentioned a few times I was talking about coolant not cpu temperatures but thanks for pointing it out

so any answers on my question barrage lol?

 

[Pf.Farnsworth]

What would be a nice quiet and small compressor that doesnt use alot of power that would work well for direct dye? I was thinking about having 3, cpu gpu gpu. I was told the average jump I would see in my power bill from running a DD setup 27/7 would be around 7$. Was thinking if I could get away for +10$ per month with 3 compressors

any thoughts?

 

[sandman001]

What temps do you want? what heatload?

 

[Pf.Farnsworth]

-20 would be fine probbably. I am leaning again towards a chiller. Pondering what gas to use. Have been looking at this chart from OC guide:



========================================================
6) REFRIGERANTS

There are many refrigerants in existence which we can obtain, some of which require us to be certified in refrigeration. I will make brief mention of these but will mainly focus on those which can be acquired by anyone.

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These are what I consider a Class 1 refrigerant. By this, I mean they were manufactured for the purpose of being used as a refrigerant and will require a certification to acquire. These require no additives to compress properly, have a long life span and are for the most part non combustible, BUT they do release chemicals which are dangerous to the ozone layer.

Here is a list in order of common use.

1. R12 (dichlorodifluoromethane) was the standard in refrigeration for a long time. With a boiling point of slightly under -21C, it was used widely in automobiles, refrigerators, window air conditioners - just about everything.

2. R22 (chlorodifluoromethane) is the refrigerant that has held the standard for home air conditioning longer than any other and is still in use. Its boiling point is just under -40C.

These refrigerants have been in use for years and have been proven time and again reliable and efficient; their only down side is they deplete the ozone layer and thus require special certification. As a result, they are typically only available in 30lb or larger canisters. These refrigerants come pre-bottled with mineral oil, so your compressor will need to be adjusted accordingly.

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Class 2 refrigerants are refrigerants that are commonplace and easy to acquire. These do not require special certification nor do they damage the ozone layer.

1. R134A(,1,1,2-tetrafluoroethane) has a boiling point of only -26C; it is becoming the new standard in refrigerators, automobiles, and all other common uses.

2. R290 (propane) is also beginning to make its way in as a mainstream refrigerant. With a boiling point of -42C, it is more of a class 4 refrigerant, but because of its new found common use I have included it in my class 2 list. This is randomly used in things such as freezers - a lot of hobbyists use it for home built systems.

These refrigerants are quite affordable; also to be noted is that they come bottled alone or with ester oil, require no certification and do not damage the atmosphere. As a result of these factors, they are readily available to the public.

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Class 3 refrigerants are those which have a lower boiling point than standard refrigerants. Often they are hybrid mixtures of class 1, 2 and 4 refrigerants.

1. R404B (pentafluoroethane/1,1,1-trifluoroethane/1,1,2-tetrafluoroethane: 44:52:4%) This is one refrigerant often sought after by overclockers. With a boiling point of approximately -44C and available in 12oz cans, this can be a nice choice provided you have your certification.

2. R409A (chlorodifluoromethane/2-chloro-1,1,1,2-tetrafluoroethane/1-chloro-1,1-difluoroethane: 60:25:10%) This refrigerant has a boiling temperature of -47.8C; you have to purchase 30lb cans.

3. R508B (trifluoromethane/hexafluoroethane: 46:54%) This is one of the best readily available high end refrigerants there is. With a boiling point near -50C, you are lucky to acquire this.

4. R-14 (1,2-dichloro-1,1,2,2-tetrafluoroethane) Ranking in with a boiling temperature approaching that of -150C at 1 bar pressure, this refrigerant can deep freeze you faster than you can say lickity split. Provided you are running either a cascade cooler or are have a compressor that can withstand approximately 350psi, it's a pleasure to work with.

These refrigerants have a moderate - substantially lower boiling point than normal refrigerants. Some can be acquired in small amounts, others have to be purchased in 30lb cylinders.

The biggest issues with refrigerants like R14 is that with its so low boiling point, it requires a lot of pressure to compress to liquid. With this in mind, it may be better to juice up a system that is running on a lower grade refrigerant by adding 10-25% more.

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Class 4 refrigerants are natural gases. These can be acquired from just about any chemical supply place - some can be located in your own home. These generally have an extremely low boiling point and are difficult to compress due to their weight, but can easily be used as an additive to an existing system to squeeze it for a few extra degrees. These, as you may have guessed, do not come packed with any kind of oil additive and therefor can be used in any system.

1. R50 (methane) This a moderately light gas with a boiling point of -162C; it's the base compound for most of today's refrigerants. In its pure form, it is a bit too light (molecular weight 16) to work with outside of a cascade cooler. Though this can be used in a system of its own, you will need pressures nearing the 450 mark on a warm day to liquify. Overall a great additive or for use in a cascade cooler.

2. R170 (ethane) This gas has a boiling point of -88C and a molecular weight of 30. It's a much more suitable stand-alone refrigerant than R50. There are a few commonplace refrigerants that are based on this gas.

3. R744A (nitrous oxide) This is a pretty commonplace gas these days; with a molecular weight of 45 and boiling point of -89C, this definitely yields some potential, not only as a stand-alone refrigerant but also as a cascade refrigerant.

4. R717 (ammonia) This is used in many commercial refrigeration systems. Although it has a rather low molecular weight (just under 18), its boiling point of -33C makes it rather easy to work with. The most widely occurring problem with this gas is its smell and, as it is slightly corrosive, extra precautions must be taken.

5. R740 (argon) Coming in with a weight of approximately 40 and a boiling point of -182C, it is easily compressed and, used in conjunction with 25% R134, has a weight which is easily used in a standard air condensed system to maintain a boiling temperature below that of -120C with less than 300 psi. This has a lot of common potential.

6. R764 (sulfur dioxide) This gas has the scores - all around molecular weight of 60 and boiling temperature of -76C, although it has toxicity issues. Given a bit of precaution not to let a lot of this loose into the air, it will easily yield quite impressive results.

These gasses have quite low boiling points, which would make them all great candidates for a cascade cooler. For those of you who don't know, a cascade cooler is simply a Phase change system that uses another Phase cooler to cool its condenser, so you can use a very low temperature refrigerant at a decent psi rating.

Each of these gasses has some sort of hazard rating, but then again all refrigerants do. You will need to acquire these liquids compressed or change them yourself, if it is going to be the only refrigerant in your system. If not, adding them in at normal gas phase is a viable option.
========================================================

Any other nice refrigerants out there?

By the way if you have coolant at -50C / -100C what would you use for cooling lines? I mean the plastic once we use for water cooling would become way too brittle.

 

[sandman001]

Wait wait, did they just say that R14 and R50 and all those can be used in stand alone systems? I hope to god they didn't mean non-cascade systems.

It's called a critical temperature.

 

[koontz946]

4. R-14 (1,2-dichloro-1,1,2,2-tetrafluoroethane) Ranking in with a boiling temperature approaching that of -150C at 1 bar pressure, this refrigerant can deep freeze you faster than you can say lickity split. Provided you are running either a cascade cooler or are have a compressor that can withstand approximately 350psi, it's a pleasure to work with.

....


1. R50 (methane) This a moderately light gas with a boiling point of -162C; it's the base compound for most of today's refrigerants. In its pure form, it is a bit too light (molecular weight 16) to work with outside of a cascade cooler. Though this can be used in a system of its own, you will need pressures nearing the 450 mark on a warm day to liquify. Overall a great additive or for use in a cascade cooler.