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Is someone willing to give me a good amount of technical advice concerning heat dissipation using a Peltier device ? Answered

Ok, I have a laptop that I use to play many videogames with, and as you can imagine, it has an overheating is a problem. I have software that monitors the GPU and CPU temperatures while I play. The GPU and CPU are rated at a 100c max temperature. Now that the summer season has started, my laptop gets hotter and hotter as I play. I am usually forced to Under-volt my computer so that it stays below safe temperatures.

Now, I was digging around online and came across something called a "Peltier device". It is a small ceramic plate (with electrical nodes inside) that when electrified, transfers the heat from one side to the other. The peltier I got is rated at 545 watts, 32 amps, and 18vdc, and gets as cold as -60c, 150c. I ordered a desktop power supply online, along with 2 CPU cooling systems. (I.E.  2x Professional grade heat-sink, and 2x 120mm fan) The Power supply outputs 430watts, 28 amps, and 12vdc.

I planned on taking these parts and simply sandwiching the peltier between 2 heatsinks, having 1 hot heatsink+fan and 1 cold heatsink+fan. I planned on pumping the cold air into the air intake on the bottom of my laptop, and just pump the hot air into the room. 

Unfortunately, the problem I face (and this is a really stupid mistake) was that I did not measure out this whole assembly. It turns out, the peltier face plates are roughly 2.5" x 2.5", whereas the heat-transfer faceplate of the heatsinks are only about 1.5" x 1.5".

Now, I wired this all up, and put it all together, ignoring the parts of the peltier that were hanging off and lo' and behold, the peltier worked as designed, one side got extremely cold, and the other got hot. The only problem is, over time, since nothing was drawing the heat away from the edges of the hot side, it transferred over to the cold side, thus warming it up to about room temperature, negating the entire purpose of the contraption. 

This is the part that I need help on, would simply taking some aluminum plates that are large enough to cover the entire surface of the peltier, smother both sides in my remaining thermal compound, and then connect this aluminum (with more thermal compound) to the heatsink? This contraption is essentially meant to be a laptop cooling pad. Mounted inside of an old computer case. So it needs to be mobile (IE, liquid cooling is not an option). Can anyone think of a better solution to this? 

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mpilchfamily
mpilchfamily

8 years ago

You will need a CPU cooler on the Peltier to manage the heat coming off it. Not one of those little stock coolers but one of the larger ones with heat pipes. Consider most of the wattage you are dumping into the cooler is being turned to heat. So you have a 200W or more heater on the back side of that thing.

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frollard
frollard

Answer 8 years ago

+1

Heat output of a peltier is Energy Transferred + Energy Added to cause the peltier effect.

@author; yes, you could just 'add heat spreaders' to make the peltier more effective with the smaller heatsinks, but as mpilch says -- Get a big heatsink, you're gonna need it.

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schwerlin
schwerlin

Answer 8 years ago

http://www.newegg.com/Product/Product.aspx?Item=N82E16835103065
As posted in the other reply, the above cpu cooler is the one i bought 2 of. It has heatpipes, and a 120mm fan. I plan on buying a large ammount of thermal compound to accompany both sides. The problem I cannot find a good solution to, is that the faceplate of the peltier, and the faceplate of the cpu cooler are 2 different sizes. So therefore the edges of the peltier get extremely hot, and might even crack the ceramic its cased in. The heatsinks do a great job at dissapating the hot parts they are pressed against, but its the edges im worried about. The only thing i could think of, was to glue 2 chunks of steel that will cover ALL of the peltier, and share the heat of the edges with the heat of the center, so that at least the whole peltier is the same temperature to prevent cracking due to uneven temperatures. But I was wondering if anyone had a less brute force, more thought out, solution.

Thanks for the quick response!

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frollard
frollard

Answer 8 years ago

Right, and as I said, YES, you could just add heat spreaders to ...spread...the effectiveness of the smaller heatsink to the entire peltier, but it is BETTER to get a full sized heatsink.

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schwerlin
schwerlin

Answer 8 years ago

http://www.newegg.com/Product/Product.aspx?Item=N82E16835103065
This link is the cpu cooler I ordered. It has copper, direct contact, heatpipes. and a 120mm 12vdc, .4 amp, 44.03 CFM (airflow) rating. It is not low end, and should have no problem conducting and dissipating the heat.

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lemonie
lemonie

8 years ago

What exactly does "Under-volt my computer" mean in real terms?

L

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schwerlin
schwerlin

Answer 8 years ago

Using MSI afturburner, I lower the shader, memory, and core clocks of my gpu. I usually underclock by about 40%, which allows me to hover around 85c.

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schwerlin
schwerlin

Answer 8 years ago

So, I literally am limiting how much power my laptop will send to my GPU and CPU. If you have an excellent cooling system, people often OVERvolt their cards, which offers an increase in performance, whereas UNDERvolting decreases performance (and the card makes less heat). I don't ever plan on overvolting my laptop, just simply running it at standard voltage, at a standard clock speed is my goal.

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mpilchfamily
mpilchfamily

8 years ago

If your having to go to this extreme to cool your laptop there is something wrong. Laptops will get hot and if you are using it in your lap or on a soft surface where the vents are being blocked it will overheat. If you've had it for a year or more you may have a buildup of dust in the laptop's heat syncs drastically reducing there effectiveness. Get a can of air and try blowing them out really good.

Granted many larger laptops with 17" or larger screens that are considered desktop replacements or gaming laptops are pushing there limits as far as there ability to dissipate heat. But a simple laptop cooling pad with a built in fan should be all that is needed. Even raising the laptop up about 1/2 an inch should help.

Is the monitoring software you are using setting the 100C limit on the CPU and GPU? What temp monitoring software are you using? Has the monitoring software been configured to work with your laptops hardware? Is the laptop case getting hot enough to burn you? What laptop are you using?

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schwerlin
schwerlin

Answer 8 years ago

Ive had the laptop for about 6 months, it has never seen summer weather yet.
It is the levono y570, it has a GEforce gt555m GPU (entry gaming level class I card) and i5 2430 CPU. The manufacturer rates the GPU and CPU at 100c max, not the software. I have already opened it up and dedusted. It is simply the warm weather preventing the laptop from cooling efficently, so therefore, i planned on making my own 'cold weather'.

If its worth doing, its worth overdoing.

I use msi afterburner to monitor the gpu temp, and coretemp to monitor the cpu temp. Both are universal software, and read temperatures based on the internal chip sensor.

Thank you for the quick reply!

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schwerlin
schwerlin

Answer 8 years ago

The problem with the laptop is that it has a GPU that gets hotter than the cooling system can handle. Since it is not a 'gaming' laptop, they didn't put anything special into the cooling system. I plan to add what it needs to keep it under 90c.