Here’s the situation. I use a laptop at work, and at the end of the day I have to put the laptop in my backpack and ride my bike home. In the winter there was no problem, as the heat from the bottom of the laptop was transmitted through the backpack and jacket to warm me up. Now it’s June and it’s not fun anymore. I work in a chemistry lab with an abundant supply of liquid nitrogen, and I’ve been thinking about the best way to apply it to the laptop to cool it off quickly without doing any harm to it.
The three things that worry me the most are:[list=1]
[li]The LCD screen. I don’t want anything near it. I can just imagine pouring N2 over the top of the laptop while closed and a second later hearing the snap!. Not too terrible an issue, it should be easy to keep the N2 off the screen while getting it to the hot parts on the underside, but a consideration.[/li][li]The innards. Do PCBs crack easily under thermal flux? What about RAM, hard drives, capacitors?[/li][li]Debris. Will the N2 collect dust, particulate matter, etc., and leave gobs of it inside to muck up the works? This happens when N2 is thrown on the floor, it skitters around, collecting all sorts of crap until the N2 has evaporated. If a gob got somewhere important short circuits (for example) could occur.[/li][/list=1]
So, dopers, am I insane to even think this is a good idea? What do you think about the utility of dry ice for the same purpose?
Disclaimer: Liquid nitrogen is dangerous if not handled properly. It will freeze you (unless you make proper use of the Leidenfrost effect and can cause asphyxiation in closed areas. Don’t do what I’m asking others if I should do. I may be an idiot.
See this thread (there are lots of others) for some liquid N2 fun.
uhhh liquid nitrogen around ur pricey laptop(i assume?) i wouldnt risk putting liquid nitrogen around any of my pricey belongings… i saw the engineering students i think do a presentation using it and they froze a rose and then it crumble under little force…so why don’t u just take the bus in the summer its only a few bucks
Yeah, don’t do that. Why not get a couple of those refreezable ice packs and toss those in your backpack? Of course you want to keep condensation off the laptop, so wrap it up in a plastic bag.
Is there a way to blow nitrogen-cooled air over the laptop, as opposed to just pouring N[sub]2[/sub] directly onto it? I’ve never been warned specifically about this, but direct contact with liquid nitrogen seems certain to damage the delicate inner workings of a computer.
I agree with Q.E.D. about the refreezable ice packs. If you must play with N2 though, what if you poured some into a styrofoam bucket and set your laptop on top of it? Hot air currents would travel from your laptop to the N2, which results in cooling down the laptop.
I have no idea if that would actually work or not. I did used to work in a microbiology lab, and I know my face would get cold while looking for tubes in an N2 bath. So I think I have the basic idea right.
Wow, a subject I’m actually an authority on. I do warranty repair on laptops. Lots of laptops.
I have yet to see one that has had a pleasant experience with anything in liquid form. It’s an excellent way to void any warranty you may have. Even a drop of moisture on the motherboard or IO section, for example, will eventually corrode. Maybe not immediately, and maybe not disasterously, but eventually. Such damage is pretty obvious, too, so if your N2-cooled laptop suddenly refuses to boot, don’t expect a free fix.
A simpler idea would be to make sure the heatsink has an adequate supply of thermal grease. In most of the laptops I open up, the original factory ‘dab’ll do ya’ is too small.
There is actually a production water-cooled laptop or two, but I wouldn’t want to fix it when that tubing breaks.
As for putting new tubing instead an existing fan-cooled laptop, good luck. There’s no room.
One of the biggest killers of computers is thermal stress. This is one of the things that leads to the whole debate over leaving a computer on all the time or turning it off when not in use. Quick cooling is going to put a lot of strain anywhere there are dissimilar materials present, most notably where the itty bitty wires inside the integrated circuits connect to the silicon. I’ve seen nice microscope pics where these wires have lifted up off of their pads due to thermal stresses, effectively killing the IC. Solder joints are also going to suffer, especially if you have a cold solder joint (a manufacturing defect that will be aggrivated by thermal stresses). I fear your laptop is going to die a very early death if you regularly cool it quickly.
Maybe you can stick a piece of styrofoam between the laptop and the part of your backpack that touches your back?
Of course an even better solution is to find something cool to set the laptop on while you are working. This will not only prevent it from getting hot in the first place, but will not have so much thermal stress placed on the electronic components, and as a side benefit since the entire laptop will run cooler it will last a lot longer.
Well, no, not exactly. The CPU has refrigeration tubing running through it that carries the coolant. Most systems use standard vapor compression refrigeration to cool down to about -40. There is some information on computer cooling here. It’s a bit technical, but an interesting read.
It’s not only supercomputers. Some people (usually overlockers) have immersed their desktop computers in liquid silicone or mineral oil. You have to leave the drives out of the coolant, which is easy enough for a desktop case but rather difficult to arrange with a laptop.
In addition to the direct effects already described, I can say with authority that where there is N[sub]2l[/sub], there is condensation. Condensation is a Bad Thing in laptops, for the reasons Barton described.
The simplest solution, assuming that the only concern is the discomfort involved in carrying a hot machine around, is to add a layer of insulation inside the backpack. Closed-cell camping foam should work well, and have the added benefit of cushioning the laptop a bit more.
Yeah, Q.E.D., I won’t do it. I was just thinking really hard about it and wanted to hear some good reasons from other people why I shouldn’t.
I agree with engineer_comp_geek and Balance that thermal stress and condensation, respectively, are bad things as I pointed out in points 2 and 3.
Some form of indirect cooling is obviously in order. I can’t easily add foam/insulation to the backpack since it’s one of those made specifically for laptops and there’s no room.
What do you guys think about this: Place laptop on pan/cookie sheet/lunch tray, etc. and pour in just enough N2 to cover bottom of said container. Cool off bottom of laptop (case only), no condensation inside…grasping at straws perhaps?
Anyway, if anyone else has comments I’m still listening.
Laptop base covers are not solidly opaque deals. They have holes for screws and whatnot, as well as various panels. You’ve got a thin veneer of plastic with maybe another flimsy sheet of paper or tape, then you’re in silicon territory. A few millimeters, really. Plus, most covers have cracks, some barely visible… you see where I’m going.
I’m trying to figure out how you suddenly cool a laptop without condensation collecting. You have hot air in the laptop, and you cool the bottom suddenly. Moisture condenses on the bottom plate. What am I missing?
Before doing anything drastic, I’d try putting something under the corners of the laptop, to let air circulate. A google search on laptop cooling came up with severalvendors who want to sell you a pad with fans in it to do that more efficiently.
Basically, I think you’re better off trying to keep the laptop from heating up in the first place, rather than trying to cool it down afterwards.
Well, plus, you run the risk of cracking your laptop’s housing all to hell with repeated rapid heat/cool cycles. Eventually, the plastic will have a fine network of cracks running through it and crumble like dust.
Wait, wait, wait. What else am I missing here? Can you not simply turn the thing around in the backpack so the bottom is not against your back? The top (screen) of my laptop does not get appreciably hot.
It looks like everythings, been covered, and that’s a “no”. My first worry would be dissimilar contraction causing cracks on the mainboard, followed by condensation when warmer air is blown through it, with some plastic case damage later with repeated sudden cooling. Not good. Other similar cooling methods have been mentioned, but the big difference is that you want to remove your laptop eventually.
I think jackelope has the right idea: Introducing cooled air into your laptop while at work might help, but that’s a bit trickier to do. Really, liquid nitrogen is too cold for your purposes. Something warmer would be better, but would of course lack the evaporates-into-nothing feature that makes it so attractive in the first place.
Sorry, Jake4. I don’t think you get it. Any kind of rapid cooling is asking for trouble. Even if you avoid condensation, you still have a metal fatigue problem.
You best solutions are to find some way to prevent it from getting so hot, or find a way to live with it. Someone suggested putting it in your backpack backwards, with the hot side away from you. Is the backpack so cramped that even a sheet of bubble wrap won’t fit?
If you have to use liquid nitrogen, at least build yerself a heat pump.
Liquid filled laptop stand with a couple hoses to a motorcycle radiator sitting in a bucket full of liquid nitrogen. Fill with really good antifreeze and then find a way to circulate.
