Water cooling on laptops

I was just wandering why there is still no laptop computer with watercooling and had a design in my mind which may work. Since the LED screens are getting more and more common and these creens occupy less space and provide less heat, why not have copper pipes that can circulate the water and cool it down between the screen and the screen cover. This will also allow the manufacturers produce thinner computers since there will be no need for a fan and one heatsink can go through the gpu, cpu and chipset. Instead of water you can also use other stuff which can cool down faster. Think about a design where you have some kind of clear pipes carrying neon liquid at the back of your screen and have parts designed for desktops installed. The chips and the boards for GPU and CPU are not any thicker than 1 cm over all and a heatsink which can carry the liquid can be as thin. So you can build a computer less than inch thich with sli, desktop cpu etc etc. Any ideas?

 

Wouldn't the back of the laptop be quite a bit thicker then? Copper pipes alone won't be able to dissipate heat, you need a radiator of some sort. I've seen some designs for water and even phase change cooling for notebooks but I guess it hasn't really taken off in the mainstream... then again even for desktops, it isn't mainstream. If they used the back of the laptop for convection via fins, it would eliminate fans at the expense of an ugly looking finned cover and much thicker.

 

...this sounds insanely heavy. May as well get a desktop at this point?

 

I am not talking about copper pipes from your sink. I am talking about very think and long pipeline which draws a zigzag at the back of the screen. I was thinking about a 7mm thick pipe and the copper should be 2mm thick. It may add add a quarter pound weight but it will save space from the bottom of the computer. It does not have to be copper. It can be aluminium too which is much lighter. Plus since the amount of liquid is not going to be excessive we should be able to get away with a pretty small pump.

 

Ok well you still need a radiator along with that you need a fan to blow across it. Also you will need a pump. Just no it wouldnt work i think.

 

Why do I need a radiator. I am putting the pipe at the back of the screen just to do passive air circulation. We can have holes at the back of the screen for the circulation. That is why I said it would be nice to have neon liquid. And the pump can be a tiny one since the liquid that will be constantly traveling in the computer is not going to be more than 50ml.

 

Ok now your getting expensive. Also what about when the computer starts heating up the point where it cant dissipate the heat fast enough? Your going to be slowly baking the laptop i think.

 

a. what do you propose for conduction?

b. even an elephant flaps it's ears to cool down it's own blood. you still need air flow to cool down the coolant behind the screen.

c. anything with plumbing has to be serviced with gaskets and o-rings.

d. the pump has to be exactly regulated. too much flow and your pumping hot liquid back around the chips. too little flowrate and you get no cooling whatsoever.

 

Pipes don't offer enough surface area to dissipate the heat. And if it's a metal pipe, you won't see the neon liquid. If you calculate the heat requirements from the computer, I doubt 50mL will be enough.

 

Additionally, without a Radiator, you may not cool the liquid fast enough as Tippey has mentioned. The high heat capacity of water means it stores a ton of energy per increase in unit of Temperature, on the other hand, it is the same in reverse. It takes a ton of energy to cool that water back down to a point so it can continue removing heat from your system.

Despite the fact that water boils at 100 degrees Celsius, it doesn't boil "evenly". Some particles will gain energy faster than others, and covert to steam, and this will greatly reduce the cooling capacity of your fluid. You have to have an active cooling source of some type, passive cooling isn't going to cut it. Especially when gaming, as some GPUs can easily reach 80+ degrees Celsius.

 

Expensive? Why?

How is this any different then the copper heatsink you have on your laptop whne it comes to the heat dissipation? You have a fan that is blowing the air from the outside to the copper and by this way keep the copper cold enough so that the CPU or GPU stays cool. With the water cooling especially if we use the aluminium, the heat will be dispensed at the back of the screen. I am thinking about a 4 feet long pipe which is very thin and draws zigzags. I don't have a lab to test this but I am pretty sure a heat transfer from a 4 feet long water pipe is much better than a thich 4 inches tall copper heatsink.

 

The air intake systems that cool the copper take in room temp approximately air, and then cycle it past said warmer metal, and spew the heated air out. The air isn't reused.

In your liquid cooling system, the fluid is reused. Higher heat capacities of fluid versus air mean you'd get a stronger cooling effect INITIALLY, but over time with only passive cooling... you'd probably end up boiling the water. If you hooked up a cooling system to a hose for example, and kept a new supply of water constantly flowing in while the heated water was discharged, then your idea works. However, that's also called a fountain. >_>

 

At best I can't see this doing anything other than moving weight from the part of the laptop that rests on the table to the screen. This would make the laptop less-stable and harder to use when at anything but a desk.

The smaller your tubes the resistance to the fluid and the more power it will take to run. Since your system as you suggest would have only a small block for cooling near the die itself any pump failure would be extremely dangerous. Most pumps are big, loud, inefficient, and expensive.

Let’s not forget that pump flow is severally affected by the difference in height between the pump (low point) and the highest point. Laptop closed, open, screen at different angles? You better have sensors to know exactly what’s up, otherwise your flow will not be the same even with the pump drawing the same power.

What happens if someone turns the laptop upside-down? That makes the pump the high point and if there is ANY air at all you could easily stop all flow, are you now going to include two pumps at the highest and lowest point or hope that your system never experiences any air in the system.

And it gets harder still; some CPUs have a design spec that allows for 95’C, if they get any hotter you could have issues with the coolant boiling – no more pumping – Uhoh! Can your system handle being pressurized if coolant boils? On the other side what happens if you leave your laptop in a car during winter? The system could freeze if you aren’t prepared destroying the entire cooling system and dumping the fluid on the electronics and screen at the moment of breakage and when it melts again. You better not have a conductive fluid.

The only systems I have ever seen had quick-disconnect fittings to connect with external pumps, external reservoirs, and external radiators. They only worked when docked at the desk in a climate controlled room and were purely for proof of concept. At best they were used for a short time to show increased over-clocking possibilities and then forgotten about. A desktop would be cheaper, less risky, and work better. It’s not like you can move the laptop easily anymore.

When you figure all this out, I am sure there are many more issues to be found with any real prototype. If not, then I suggest you make it since such a system would be worth a lot of money.

 

Now we are talking. Think about the netbooks or macbook air where there is no ventilation altough there is heat being generated. The whole body of the computer acts like a heatsink to disperse the heat. In our case, the longer the liquid (I am saying liquid since it may be better to use some other type of liquid) travels at the back of the laptop, the cooler it will get since there is no heat being generated at that part. Also I don't know if there are any other conducter type of pipes which are clear. I know glass is not going to do it since it is not a good conducter. With aluminium you can even increase the length of the pipe to 6 feet or more depending on the computer size.

One other idea, if you have to have a fan to run air on the pipes, you can also add mini fans to the top of the screen where the webcam usually resides. 4 mini fans blowing air through the pipes should solve the air circulation issue if necessary.

 

you're better off using a laptop base with thermoelectric cooling. cheap setup. cool surface and direct cooled air directly into the laptop intake.

 

as a matter of fact, i'll develop it . i have patent rights since i documented it right here.

 

The main purpose of this setup is not creating lightweight computers but creating portable desktop class computers. The liquid can not be water. It is a given. It should be some other liquid with high conductivity and wider heat range. So it won't boil and freeze between -10 to 120C which I think is not that much to ask. The base of the computer is still going to be pretty heavy due to the pump and the optical drive, hdds, mobo, cpu, gpu etc. The nice thing is you will have more space for the GPU and CPU. Without the fan and stuff the thickness of a desktop GPU is less than a cm. why not put 2 dekstop GPUs in a laptop and cool it with liquid. I am not talking about $500 laptops obviously but there are so many people who spend $4-5K on laptops just to have the best. I am talking about a new segment of notebooks where we are not using last years desktop components.

The location of the pump does not matter since the amount of liquid that is being circulated is not that much. So yes, the pump should be powerfull enough to circulate the liquid easily through the pipe. Still it does not have to be any larger than 1-1.5cm cube.

 

It would be awesome if they really do it .

 

one way to do that right now is to develop a cooling plate that you could insert between the chip and the heatsink. the plate has two external ports, inlet and outlet. the plate is jacketed for coolant. lines are plumbed outside the laptop. then you can optionally run coolant through the plate through whatever means you devise.

my patent rights #2.

 

Dude, you are confusing me.

 

Dont you think it would be better to continue the way they are currently which is into smaller more energy efficient, cool running chips?

 

which part?

the plate makes contact with the chip much in the same way a heatsink does.
it's thin and has passages (jackets) within it through which coolant can flow.
there are two coolant ports off the side of the plate to allow ingress/egress of coolant. the ports are plumbed to the outside of the laptop and can be connected to any cooling system you desire. ethylene glycol, propylene glycol, water mix, etc. water, btw has the best cooling properties of any liquid.

 

Most of the research departments look into multiple ways of increase efficiency. Smaller and more energy efficient chips are very important but look at the cars we are driving. Altough the dngines are more smaller and energy efficient the gas consumtion did not change dramatically because now we have alot more electronics and safety features in the cars. They are heavier and go faster too. I am talking about a desktop class laptop with an inch thickness.

 

Water may have the best cooling specs but for the temps we are talking about it can cause issues. I still don't believe that any laptop computer can boil water with the right dispersment.

 

the issues with water are oxidation and electrical conduction. the glycols are lousy with heat transfer. you'll overheat any system with glycols alone but they add the necessary anti-freeze and boil over properties. Water alone is an absolutely amazing medium.

 

Ok, we are back top water cooling then. Do you have any suggestions for the material of the pipe?

 

Liquid metal cooling expensive as hell but easily 10x better than water. Either way you design the pipes, the surface area to volume ratio won't be enough. Too small width will limit the velocity while too big will limit the heat dissipation. Peltier cooling is too inefficient and phase change is a lot better than standard water cooling. Most desktop air cooling have heatpipes filled with liquid that evaporates. The gas then easily rises and gives off it's heat to the heatsink part. The problem here is size since these liquids don't hold a lot of energy (in terms of what needs to be dissipated).

 

Have you looked at how much piping is needed in a water cooling system? And the thickness? This would not work in a laptop due to form factor.

 

Liquid metal cooling isn't worth the cost nor the time. Sure, metals absorb heat quickly but they also retain it, right? A coolant must be able to quickly shed as well as absorb. You couldn't cool the stuff off in time for it to recirculate back. Further, whatever you've devised to cool the coolant, you should have applied directly to the original problem, the hot chip.

 

Metals do absorb quickly but by that same process must release it quickly too. Which is actually preferable then water's holding in the heat. It's better to quickly get rid of a little bit of heat as it is generated then build it up. Liquid metal has lots of potential as it can perform a lot better than a water cooling system, but as with most new products, the big factor is cost.

 

I would say that this is possible, but not on a micro thin laptop.

Passive radiation of the heat would work but you are talking micro fine copper tubes that are bundled up on the back of the monitor to allow cooling. If you parallel up enough then the surface area will be large and the flow will be good enough for cooling. A clever design of back cover could induce convection of air up and through the back of the monitor to cool the tubes (hot air rising out the top can pull cold air into the base to cool more effectively).

The biggest problem will be the pump. I have yet to see a small pump that can provide the flow needed to keep everything cool. I use a small pump on my HTPC that has an old and hot Q6600 B3 chip and P43 northbridge. This pump produces 500L per hour running at 12v, my loop has 2m of pipe from the case to the radiator so flow rate is very low at about 200Lph on 12v and I run the pump at 7v which is enough to get about 50L per hour. This is a very slow flow but is still enough to give me a max core temp of 47C running intel burn-in test at full speed so cooling a laptop with a power efficient chip and low flow rate is very viable.

If a very small pump can be designed or found (could use a pizo-electric tube rather than a mechanical pump) along with a thin water block for the GPU, CPU and motherboard chipset, or even a cooling plate on the base that can have blocks that are raised to touch the chips, then it is very viable.

Most of use already have a simple form of water cooling in the PC's we use. Most heat pipes are water based and use the evaporation of water under a vacuum (lowers the boiling point) to generate low temp steam that flows towards the cooler end and condenses back into water which then flows (either by gravity or a wick arrangement) back to the hot end of the pipe.

 

In case no one mentioned this:

Pipes of any case can brake seemingly without reason.
(actually there is a reason - internal pressure, maybe slight impurities grinding material away, minimal movement)

Basically: In a laptop, when it gets carried around a lot it may get dropped, banged against stuff - then, every time you settle it on your table - its possibly less gentle than you think.
(I had my HDD protection come on even though I didn't bang it...)

Thus these pipes would be under a lot of strain which means they are liable to breakage. For the same reason having a cooling system at the back of your screen is a no go - the joint will leak.

You could possibly have a very small circut for say the GPU or CPU only - but this'll then need to dissipate heat - and if you build a refrigarator style pump this'll produce more heat, and and and...

 

...It's a bit of both.

Water has specific heat capacity of roughly 4.19 kJ/kg*degree Celsius. So it takes 4.19 kJ of energy to raise 1kg of water up 1 degree Celsius. When you look at this figure, it takes a relatively long time to heat up the water, so water can absorb a lot of energy (energy transfer will occur from object being cooled to water so long as the water is cooler Temps wise).

By the same merit, water releases a lot of energy when cooled, or, in otherwords, takes a long time to cool if passively cooled, by air for example. (Think convection air flow by day and by night near a large body of water, or at a beach. In the day at a beach, it's cooler at the beach than it is say... in the city, because the air around the beach is giving off heat to the water, heating it up, so the air stays cool. At night, the water has spent the entire day being heated, and now gives off heat, so being on a beach at night will be warmer than in a city.)
The reason it takes so long for air to cool water is because the air closest to the body of water has a considerably lower heat capacity, so a much larger amount of air is required to cool a small amount of water.

In the case of metals (with regards to liquid metal, I don't know what kind of heat capacities they have, I'm going to assume they're very close to the solid metals themselves.) they have low heat capacities, so for the same amount of energy water absorbs to become warmer by 1 degree Celsius, the metal would probably rise a few degrees Celsius. Likewise, because of this, a smaller amount of energy removed would result in the same 1 degree Celsius drop.

Pros of water cooling:
absorbs a lot of energy for a small temp increase
can absorb a lot more energy per unit amount of water, thus you don't need a whole lot of water

Cons:
must be actively cooled after a certain point.

Pros of liquid metal (...isn't the only liquid metal Silicon.. what kind of crazy things are they developing these days...)
cools very quickly
can be use to cool devices that exceed 100 degrees Celsius in operating temps.

Cons:
does not absorb a large amount of energy
would have to be actively cooled just to maintain liquid metal temp below whatever the object you're cooling is.
if passively cooling, you'd need a heck of a lot of this.
weight? ? heavy as heck?

 

I think there is some Metal called "Gallium" that will melt in your hand...

And silicon isn't a metal as such - neither is it a non-metal - its in between.

By the way - just to be picky:
Isn't the literature value for the specific heat capacity of water
4179J/(kg * 1°) ???

 

...yea... fine... be specific DetlevCM.

...4179J = 4.179 kJ

SUE ME, I ACCIDENTALLY CAPITALIZED THE 'K'.

Thanks for the save. What is large 'K' anyways? If anything at all.

 

Don't take offense - but look at your post - it's just that 4,179 rounds to 4,18 rather than 4,19. (That's what I was referring to with being picky - although its not clear)
4,2 is used at least in schools...

Very well explained by the way!

What the "k" stands for? k = kilo = 1000

 

...bleh... it's been a while since jr high science. Heat capacity varies with temperature, so whatever.

Oh, I wasn't referring to small 'k', I know that's kilo = 1000... but, does large 'K' stand for any prefix? I know 'K' = Kelvin = absolute temperature, but in terms of quantity, does it mean anything?

 

Not that I know of.

 

Thanks guys. About the pipes breaking or leaking, I wasn't thinking about joints at all. It would be a single cobber tube bent to fit. Once again, this design is not for a $500 computer. This is for $4K+ gaming system. We can put an accelerometer to shut off the pump at the time of transportation. It can also set the fluid circulation speed. Also putting 4 little fans at the top of the screen sides of the webcam can achive the active cooling purposes. Also that location will not be covered by anything (your leg, belly or where ever you put your computer) hence will be very efficient for cooling. The most important issue with the current cooling setups on laptop computers is the location of the fans and the air circulation at that location. There are many models out there where the air intake and output are too close which causes the recirculation of the warm air. So:
1. To get effective cooling the heat should be transported as far as possible from the heat source.
2. To do that you will need a conducter which will carry the heat effectively and fast enough.
3. Heat transportation should occure in a well protected setup since any unexpected leakage can cause huge damages.

So at this point, it still looks like water is sufficient. For the material of the pipe, I suggest aluminium which is light and easier to control plus would not crack in cold temps. For the pump I found this.

Any objections?

 

Yes. Thank god I just finished intro fluid mechanics and stuff.

This is really bad. The pipe you use has to be STRONG if anything. Any other fluid than water (and water is pretty bad already) is going to cause massive strain at every bend. The greater the bend/direction change of flow, the greater the stress.

Lets say you've designed a water flow system to carry water at maybe 1 m/s(hmm.. a bit fast? I can't really judge off the top of my head. Average driving speed is 60 km/h... or 60000 m/h / 3600s/h = 16.7~ m/s), at every bend, you're going from 1m/s in one direction, to 1m/s in the other direction, so basically at each bend, you'd need at least DOUBLE the pipe strength that your straight length pipes have, assuming due to size constrictions, you minimized pipe wall thickness to just barely handle water flow in the straight regions.

My calcs are rough... it might actually be quadruple the strength. I can't remember these complex formulas off the top of my head anymore. Plus, there's all sorts of other factors involved like flow type, pipe wall roughness... etc etc... bleh.

I'm a Chem E... I'm supposed to know this stuff for the rest of my life. T_T

 

I am an engineer too but I also had an MBA so the technical difficulties are not as big as the profit margin at this pint in my oppinion. It is just manufacturers are not willing to go out of their standards.

 

i see that a properly designed and liquid jacketed plate sandwiched between the chip and the heatsink and ported to the outside of the laptop for additional cooling under extreme conditions is an extremely good solution.

during normal use, no liquid will pass through the plate and it would simply act as an extension of the heat sink.

during gaming type conditions, simply connect the ports to an outside water source which would be a container with an attached low cfm pump. turn the pump on, cold water circulates through the jacket, instant cooling.

this is a mod for the enthusiasts. far more elegant in simplicity and design than all the plumbing mumbo jumbo and liquid metal proposals.

 

Speaking of liquid metal:

http://www.engadget.com/2008/12/05/danamics-liquid-metal-cpu-cooler-found-to-be-impractical-ineffe/

That was interesting.

 

You know, the original Xbox 360 Laptop is water cooled with an internal radiator, and the guy managed to keep it a reasonable size considering how hot a 360 would get if you condensed it into a laptop case.

Here's a picture of the internals.



If you're really a hardcore enthusiast, it wouldn't be unreasonable to build your own laptop with self contained effective water cooling using a similar design.

 

Look at this

Look at the pipe that is going behing the screen from the pump. Interesting timing tough.

 

Ok - so Apple are thinking about a water cooling system - because they can't build a decent air cooled system.

Now - please do not take offense.

I say not decent air cooled system do to the statement that prolonged use on one's lap could cause burns - I know that this does not happen on my Sony Vaio.

Maybe some Macbook user experience as a counterweight?

 

I am not talking about a brand orianted subject so, apple may or may not complete this project but I am pretty sure that in 6months to a year we will have a liquid cooled laptop.

 

Maybe - although I've got a feeling they will cause a lot of headaches and problems...

But anyway, lets see...

 

IMO, hybridizing is the best solution. Water block (jacket) the heatsinks for connection to an external water supply for use only when needed, leaving the laptop to handle it's own cooling duties during normal use.

Look, there's nothing wrong with the idea of liquid cooling in laptops.

But the cooling system must not tax the system when not needed and must not be ubiquitous. Nor does a system need to be completely contained within the confines of the laptop. Doing so turns the laptop into a heater.

During mobile situations, power management takes over and the cpu steps down, making a cooling system not only redundant but would result in parasitic power loss.

What we're really talking about here is desktop gaming and otherwise extreme usage situations.

 

i understand if you're seeking to develop one for the sake of "look what i can do"

but honesty once you do that you have to carry around a radiator and reservoir on top of your laptop, you might as well lunk around your desktop.

These applications are for gamers and most gamers like components that they can easily change out. From a consumer's point of view, im thinking "whats the point?" i rather just lug my desktop to my lan.

From an enthusiast's point of view, "heck yeah! that would be cool!"

but in the end i think its a worthless thing to look into purely because of physical size and logic. If i want gaming on the go, i sure as heck am not going to buy something that weights alot, is expensive and i have to setup.
Might as well have something more powerful and less money.

For the price of a water cooled laptop thats as good as you guys are making it out to be, i can have a killer desktop rig + a good mobile unit. Not top of the line but pretty dang good.

agree or disagree that is my point of view on things.