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· Twin Turbski
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This all started about two weeks ago when I purchased a chiller for experimental purposes. I was scanning ebay/newegg one night for various different types of coolant and brainstorming on how I could come up with some substance a little more exotic than water, or additives I could use to enhance heat exchange. This is when the thought popped into my head that cooling a PC with liquid metal may very well be a viable and feasible option. And something I might actually be able to pull off, given enough time and research. One of my side topics of interest are nuclear reactors, so that was what prompted me in the first place, as some nuclear reactors are actually cooled by liquid metal and it is extremely effective, and known as the "ultimate" coolant. I want to get a few things straight so you guys don't think I've gone off the deep end:

1) This is a long term project - It will likely take at least 6 months to a year to design and build and impliment what I am envisioning.
2) This is not practical in any sense of the word - I find it very intriguing, however, and I have a very curious mind, so yes, while early on it will be experimental, I do eventually hope to come up with a liquid metal cooling "solution" that perhaps could be developed into a real product for overclocking enthusiasts.
3) This is not going to be cheap. Gallium costs about $100 for a 1/2 cup, to put things in perspective.
4) This is totally experimental for the moment, but I think I can make it work, and if I do I will try to come up with a kit or formula that other hardcore OC people can buy and implement themselves.
5) This will be a great covid project as I dont see us coming out of this pandemic anytime soon lol

I first came across Mercury, obviously one of only a few metals that is a liquid at room temperature. But this is nasty stuff, and the vapors alone are enough to keep me away, far away. Then of course there is Gallium, which I think with the right tweaking will make the most effective "liquid metal coolant" for this project. Gallium has some very cool properties and has a melting point of 85*F, which is obviously to high to be used practically in this scenario. It is also very corrosive to aluminum so all the parts used in this liquid metal loop will have to be compatible with a gallium based alloy.

Galinstan - Wikipedia
So I did a little more research and came across a very interesting alloy known as Galinstan, mixture of gallium and indium (and a pinch of tin) which has a melting point of -19*C (-2*F). I need to do more research but if I really want to take advantage of liquid metal as a high performance coolant, I need to involve a chiller in this conversation. Because in a normal loop, with standard radiators you might only see 5-10% increase in thermal dissipation properties of LM vs standard water loop. If you can get the heat out of the liquid metal very quickly, you get more bang for your buck, and can further capitalize on it's superior thermal dissipation properties. In other words, my plan is to utilize a chiller and a plate heat exchanger which will interface the liquid metal loop with coolant loop from the chiller at about 33*F. A plate heat exchanger is a very interesting piece of equipment in that it offers a huge amount of surface area verses a standard radiator, and a radiator is air to water, whereas the plate heat exchanger is liquid to liquid. So right off the bat, we will be using a highly effective form of heat transfer (liquid to liquid is far more effective than liquid to air). The project requires two independent loops, at least as I see it right now (see graphic below). The liquid metal loop goes through the plate heat exchanger where it gets cooled by the chiller (and the chiller will have it's own independent loop and the two will never touch. For all intensive purposes, a plate heat exchanger is the most effective heat exchanger for use with this kind of idea and will provide well over 20x the surface area of a standard radiator. That's the key here in allowing us to flip conventional thinking about radiators on its head, as I will outline my theory below.

My goal is to run the liquid metal loop with a target goal of maintaining it at about 35*F in that loop. And this is where things start to get interesting. In a conventional loop, the radiators get hot, because you are removing all that heat generated from your CPU/GPU. But then it dawned on me, why would I want hot radiators INSIDE my case? I mean, in the conventional sense, a radiator in a house is designed to heat the house. Do I really want 90*+ radiators in a confined space around very temperature sensitive electronic equipment, especially when I'm overclocking? The rational answer is NO.

What am I getting at? We will use the liquid metal to run the entire loop sub-ambient, so effectively, you will have 35-40* liquid metal flowing through your radiators. In other words, use the radiators to cool your internal case temps, not raise them. Because the liquid to liquid heat exchanger is so much more effective than liquid to air, any decent chiller should be able to maintain the entire loop at sub ambient temperature without to much trouble. There is a very common misconception that running radiators with a chiller is a no no, but actually, when you study it closely, the chiller should have no problem dealing with the temp increase in LM from passing through your radiators. This is effective air conditioning for your system. even if you have two or three large radiators, that's still nowhere near the surface area of the 60 plate heat exchanger I just purchased for use with this project. Yes, there will be condensation and other challenges, but one by one, I will address them.

This LM loop would require a different type of pump (electro-magnetic MDF pumps in particular would be ideal). Taking advantage of the metallic nature of the coolant, the pump pushes the liquid around electromagnetically. Unlike water cooling, the process requires no moving parts, consumes little power, and is silent.

The attraction of liquid metal itself is its excellent conduction of heat, it is 65 times more thermally conductive than water – and 1,600 times better than air cooling.

In short, liquid metal is able to absorb heat more rapidly, and thus cool down chips faster. This property has led to its use as an “ultimate” coolant in some nuclear reactors, which are cooled with liquid sodium or potassium, as well as in the manufacture of high-quality machine components, such as gas turbine blades, where the components are rapidly “cooled” to 660 C with molten aluminum to prevent the formation of defects.

Before you laugh, just know that there are proven liquid metal loops already out there, designed for use with mobile devices all the way up to servers. Nothing holding me back from taking a couple pages out of their playbook for my little project.

This project is in it's intial phases. But I am proceeding with the idea and I will make it happen. Your comments are welcome, both good and bad, just please dont post things like "dont do it" or "it wont work" because I am doing it and WILL make it work.

But your advice is appreciated because I know we have expert opinions out there who can help me or guide me in the right direction to make this whole experiment viable.

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Essentially, this layout is similar to what I am envisioning in my head (sump water would be chiller) and liquid-liquid heat exchanger in the center would be the plate heat exchanger)

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· Iconoclast
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There are definitely liquid metal coolant loops that work well for their intended purpose.

However, I'm highly doubtful that it one will match or outperform a competent water loop for PC cooling. Water may not have the thermal conductivity of Galinstan, but thermal conductivity of the coolant isn't often the limiting factor and water has a much higher volumetric heat capacity. Liquid metal loops are normally used were compactness or silence takes priority, or where the working temperatures involved are above the range of liquid water. The temperature range you're looking at is the ideal range for water-based coolants.

With regard to chillers and radiators, the reason it's generally counter productive is that a correctly functioning water loop has nearly uniform temperatures throughout the enitre loop (if there is a significant gradiant, it means your flow rate is too low). So, if you're aiming for temps that would justify the chiller, the radiator is actually going to be a heat load, not a heat sink. Yes, this could be used as an air conditioner...but why? If the main thermally significant components are already in the loop, you don't need subambient air blowing over the rest. You're just making your chiller work harder, and without temperature control to keep things above the due point, risking condensation issues. Only if the chiller can't get the coolant below ambient will having radiators in a water loop be beneficial to coolant temp, and if this is the case replacing the chiller with more radiator area is much more efficient.

I haven't done the math to see what the temperature gradient would look like in a liquid metal loop--and I suspect it could be significanr given it's higher thermal conductivity--but I also suspect the same principles would apply, otherwise there wouldn't be much point in circulating the coolant. MDF pumps also have terrible performance relative to physical impellers.

Anyway, it still sounds like an interesting project.
 

· Twin Turbski
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Discussion Starter · #3 ·
However, I'm highly doubtful that it one will match or outperform a competent water loop for PC cooling.
I agree with this statement for the most part. Part of me likes the extreme theory behind using liquid metal as coolant in your loop. So no doubt this is going to be challenging but I think I can at least break even here.
In the sense that I like being different and I've found a liquid metal alloy that has a melting point of -2*F which is low enough to have some OC potential.

So, if you're aiming for temps that would justify the chiller, the radiator is actually going to be a heat load, not a heat sink. Yes, this could be used as an air conditioner...but why? If the main thermally significant components are already in the loop, you don't need subambient air blowing over the rest. You're just making your chiller work harder, and without temperature control to keep things above the due point, risking condensation issues. Only if the chiller can't get the coolant below ambient will having radiators in a water loop be beneficial to coolant temp, and if this is the case replacing the chiller with more radiator area is much more efficient.
Yes, the radiator will be a heat load, but you have remember, I have probably 30X the surface area of all my radiators combined in a single water to water plate heat exchanger. So I have the ability to cool the liquid metal for a longer duration and with a much more effective thermal transfer (ie water to water as opposed to rads which are air to water)

So yes, you are correct, the radiators will be a heat load, but considering surface area and all the rest of it, I should be able to find a chiller that can easily cool a couple radiators and your CPU/and or GPU at the same time. I mean i never put the side cover on my case, lol but in theory, internal case temps are important in overclocking and just a few degrees can actually have a significant impact on OC reliability. I guess what sold me on the idea is would I rather have hot radiators or cold radiators in my PC?

So yeah, it's just an experiment but I think it will at least be fun to try it out and see what I can learn along the way. It would be nice to respond to a "what's your favorite coolant" with liquid metal. lol
 

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First of all, any gallium based liquid metal will react with copper and nickle. You will need chrome lining. Danamics made a liquid metal cooler but they used a sodium-potassium alloy. I wouldn’t recommend you play with this stuff; its explosive when it comes in contact with water.

Btw, the Danamics liquid metal cooler, with the electromagnetic pump, performed about as good as your standard air cooler.

My goal is to run the liquid metal loop with a target goal of maintaining it at about 35*F in that loop. And this is where things start to get interesting. In a conventional loop, the radiators get hot, because you are removing all that heat generated from your CPU/GPU. But then it dawned on me, why would I want hot radiators INSIDE my case? I mean, in the conventional sense, a radiator in a house is designed to heat the house. Do I really want 90*+ radiators in a confined space around very temperature sensitive electronic equipment, especially when I'm overclocking? The rational answer is NO.

What am I getting at? We will use the liquid metal to run the entire loop sub-ambient, so effectively, you will have 35-40* liquid metal flowing through your radiators. In other words, use the radiators to cool your internal case temps, not raise them. Because the liquid to liquid heat exchanger is so much more effective than liquid to air, any decent chiller should be able to maintain the entire loop at sub ambient temperature without to much trouble. There is a very common misconception that running radiators with a chiller is a no no, but actually, when you study it closely, the chiller should have no problem dealing with the temp increase in LM from passing through your radiators. This is effective air conditioning for your system. even if you have two or three large radiators, that's still nowhere near the surface area of the 60 plate heat exchanger I just purchased for use with this project. Yes, there will be condensation and other challenges, but one by one, I will address them.
Liquid metal specific heat is so low, it will be very hot after the first heat load. Water loops take a long time to equalize and temps generally don't vary more than 1*C with proper flow due to a very high (the highest) specific heat. You will need a heat exchanger between each heat load if you want one loop.

This LM loop would require a different type of pump (electro-magnetic MDF pumps in particular would be ideal). Taking advantage of the metallic nature of the coolant, the pump pushes the liquid around electromagnetically. Unlike water cooling, the process requires no moving parts, consumes little power, and is silent.
The pumps generate a large electromagnetic field; not great inside a computer case…

The attraction of liquid metal itself is its excellent conduction of heat, it is 65 times more thermally conductive than water – and 1,600 times better than air cooling.
In short, liquid metal is able to absorb heat more rapidly, and thus cool down chips faster. This property has led to its use as an “ultimate” coolant in some nuclear reactors, which are cooled with liquid sodium or potassium, as well as in the manufacture of high-quality machine components, such as gas turbine blades, where the components are rapidly “cooled” to 660 C with molten aluminum to prevent the formation of defects.
I don’t think this means what you think it means. Conduction is the transfer of heat through a material and only affect heat transfer at the median, predicated on the conduction coefficient and thickness of the barrier (in this case, copper). Water is just a way to transfer heat; its conduciveness means little here…

A few other thoughts:
-A water loop would perform better about 100% of the time 100% of the time. Just make a water loop with a chiller :D

-Mentioned above, research Danamics Liquid Metal CPU cooler. It used an electromagnetic pump to circulate the liquid metal through 5 heatpipes. At best it matched but generally it lost to traditional air coolers.

-Unless your pump can really move that liquid metal, the low specific heat of liquid metal is going to be a big issue. If it’s not pumped fast enough, your CPU/GPU will overheat. Again, you’re going to need individual loops for each heat load or lots of heat exchanges.
 

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Interesting idea but I see this being a big mess. Clean up after any spills would be extremely difficult, least with water you can just let it dry whereas you’d have to really clean any components if you spilled LM, if they even survive.
 

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I'm not so sure about this. I love the concept but not so sure about the practicality of this... I mean do we really need something better than water?
If you really wanted to build and outstanding loop...why not use ammonia? It's commonly used in coolant systems...besides the toxicity and potential death of a leak...what could go wrong? I think Glycol is also higher on the list which might be a possibility. I think your #1 issue that you're going to face is the viscosity of the liquid. You're going to put some MAJOR strain on that pump...not to mention the actual surface tension to try and push it through a radiator/cooling fins is going to be incredibly restrictive.
Just a few thoughts.... Best of luck! I love the concept of water cooling... I wish there were better solutions for laptop cooling since that's all I've got now...
 

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The main difference between liquid metal and water is that liquid metal would be able to conduct heat away from the fins in the block at a much lower gpm flow rate. I suspect that it would not significantly outperform any water loop that has enough water flow to reach the point of diminishing returns.
 

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I'm not so sure about this. I love the concept but not so sure about the practicality of this... I mean do we really need something better than water?
If you really wanted to build and outstanding loop...why not use ammonia? It's commonly used in coolant systems...besides the toxicity and potential death of a leak...what could go wrong? I think Glycol is also higher on the list which might be a possibility. I think your #1 issue that you're going to face is the viscosity of the liquid. You're going to put some MAJOR strain on that pump...not to mention the actual surface tension to try and push it through a radiator/cooling fins is going to be incredibly restrictive.
Just a few thoughts.... Best of luck! I love the concept of water cooling... I wish there were better solutions for laptop cooling since that's all I've got now...
Its an electromagnetic "pump" If they make one big enough for the tube sizes and volume he will need, it should work ok. Just keep your "everything in your computer" away from its electromagnetic field it will be producing...
 
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I am just wondering if this was designed for for 24/7 operation but not so much for powered down between usage?.
I guess the electromotive pump would have to be always on to keep the metal liquid.
Probable advantage is the pump has no moving parts?
It would work with any conductive liquid. If it does not leak.
 

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This can translate well into laptops
 
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The attraction of liquid metal itself is its excellent conduction of heat, it is 65 times more thermally conductive than water – and 1,600 times better than air cooling.
When you refer to air cooling, you compare it with water and liquid, as a medium for heat transfer. Air is not used as a medium for heat transfer. Water is. Technically a water radiator, is an air cooler, just the same as a heatpipe cooler.
Liquid cooling rely more on capacity and extraction (due to an active mechanism that evens out the heat throughout the loop). Heatpipe coolers relies more on heat conductivity and dissipation, which results in a less evenness throughout the cooler than with liquid cooling.
Ever wondered how a 700gr cooler on a GPU can deal with 400w no problem, but a d15 has issues with loads over 250w??

Which leads me to my next point, and why your idea won´t work.

In short, liquid metal is able to absorb heat more rapidly, and thus cool down chips faster. This property has led to its use as an “ultimate” coolant in some nuclear reactors, which are cooled with liquid sodium or potassium, as well as in the manufacture of high-quality machine components, such as gas turbine blades, where the components are rapidly “cooled” to 660 C with molten aluminum to prevent the formation of defects.
Ignoring the flow rate and the build up problems, it doesnt matter, you're still going through the same barriers, which is IHS, TIM, coldplate. The cooler the coldplate, the better the temps. Doesnt matter how you do it.

You wanna improve conductivity for CPU cooling? start removing barriers. Remove the IHS from the ecuation. You wanna go further?, remove the coldplate+tim, and go direct die to liquid in the loop (this might be worst unless something exotic like a liquid metal loop is used, cus your usual water it's really bad as a thermal conductor and the die area is too small.........for those who might feel differently, think of the water as a heat reservoir at the same time as a bad medium for heat transfer).

Hope this helps.
 

· Twin Turbski
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Discussion Starter · #14 ·
Liquid metal specific heat is so low, it will be very hot after the first heat load. Water loops take a long time to equalize and temps generally don't vary more than 1*C with proper flow due to a very high (the highest) specific heat. You will need a heat exchanger between each heat load if you want one loop.
Two seperate loops with a 60 plate liquid to liquid heat exchanger will have no problem cooling off the liquid metal.

This just arrived the other day:
It has about 60X the surface area of a standard radiator. (not to mention it's liquid to liquid which is many many times more efficient in removing heat than liquid to air). Chiller loop and liquid metal loop interface in this 60 plate heat exchanger. (see diagram posted above)








More pics to follow shortly.
 
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· Twin Turbski
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Discussion Starter · #15 ·
Stainless steel barbs installed so I can connect up to both loops (before I switch to liquid metal these might change)

I forgot to mention, it will be hooked up to a chiller with standard coolant to see the effect it has on the conventional loop. So this project is not going to happen overnight.






 
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· Twin Turbski
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The pumps generate a large electromagnetic field; not great inside a computer case…
This is no problem, I assure you.

Interesting idea but I see this being a big mess. Clean up after any spills would be extremely difficult, least with water you can just let it dry whereas you’d have to really clean any components if you spilled LM, if they even survive.
Why would I spill liquid metal? I'm not going to be doing this when Im drunk.

First of all, any gallium based liquid metal will react with copper and nickle. You will need chrome lining. Danamics made a liquid metal cooler but they used a sodium-potassium alloy. I wouldn’t recommend you play with this stuff; its explosive when it comes in contact with water.
Also note, room temperature liquid metals are free of thermal management, corrosion, and sealing issues, this is a well known fact. So no problem there either. And that's the beauty of a gallium based loop. I can actually use water with the gallium to create a "blended" loop. In other words, nothing is going to blow up, and one compliments the other.
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Not saying this project is going to be easy or cheap, but it certainly should keep me busy until covid goes away .
 
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· LTSC for life crew
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Don't know if this is helpful to you or not but this style pump is often used for highly caustic fluids or compounds that would otherwise damage a pump's blades. Might be adaptable to your idea.

It's a rotor pushing on a piece of Tygon style flexible tubing. And they work really quite well without ever coming into contact with the working fluid.



 

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Don't know if this is helpful to you or not but this style pump is often used for highly caustic fluids or compounds that would otherwise damage a pump's blades. Might be adaptable to your idea.

It's a rotor pushing on a piece of Tygon style flexible tubing. And they work really quite well without ever coming into contact with the working fluid.



I’ve used these at work and they’re all noisy. Defeats the purpose of watercooling. I’m not sure what the purpose of LM cooling is, so maybe it’s a good fit.
 

· Robotic Chemist
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I don't understand either. Unless you need 1000°C without pressurization there are better fluids than liquid metal. Water is really great if the working temperature is between 4°C and around 60°C, it is one of the best available liquids performance wise even ignoring safety concerns.

The reason liquid metal is a good thermal interface material (watts per meter K) is not that important with turbulent flow as found in a water block. Heat capacity is much more important in a pumped liquid cooling system, because the rate of heat flow into the fluid is directly proportional to deltaT, so the less the fluid's temperature increases in the block the more heat it soaks.

To design an optimal loop you need to understand the heat flow. Do not think about temperatures, think about watts.

I can actually use water with the gallium to create a "blended" loop. In other words, nothing is going to blow up, and one compliments the other.
No, you cannot. The liquid densities are too different, flow patterns would be absolutely terrible. They also react.
Oxidation of Gallium-based Liquid Metal Alloys by Water
 
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