TEC and peltier effect Good day to you all Guru´s. Today, I was thinking on a good cooler for my Opteron 146 and since I was going to get a XP-90 but now I have the chance to waste $100 dollars in a cooler I was looking around for something better than XP-90. Looking at some good cooling solutions, I found the Coolermaster Aquagate Mini 120 which comes with a 3-in-1 waterpump, reservoir and block and bundled with a 120mm radiator-fan which in some reviews it has performed better than many WC systems and nearly as the Swiftech Ultra and Corsair cool. It seemed like a very good option since it cools better than air and it costs about 90 US dollars and performs much better than Thermaltake Big Water or many more expensive WC systems. Then, in my way surfing in the Net and I found a very interesting product at the first sight. The product: Thermaltake SubZero4G http://www.thermaltake.com/coolers/subzero/subzero4g.htm I had already read many things about Peltiers and since I like a lot physics, then, I know very well how does Peltiers work. First What is a TEC? A Thermo-electric-cooler (TEC, picture above) is a small solide device that can operate as heatpump or electrical generator. When used as heat pump (which is the one we want to know about), then, its called TEC thermo-electric-cooler. If used as electrical power generator, then, its called TEG thermo-electric-generator. When its used as TEC, it uses the peltier effect to move heat. Second What does peltier effect does? How does it works? The Peltier effect was discovered in 1834. When current passes through the junction of two different types of conductors it results in a temperature change. However, the practical application of this concept required the development of semiconductors that are good conductors of electricity but poor conductors of heat - the perfect balance for TEC performance. Today, bismuth telluride is primarily used as the semiconductor material, heavily doped to create either an excess (n-type) or a deficiency (p-type) of electrons. Third Then, How does a TEC works? The procees is very simple and easily to understand. A TEC consists of a number of p- and n-type pairs (couples) as I mentioned above, connected electrically in series and sandwiched between two ceramic plates. When connected to a DC power source, current causes heat to move from one side of the TEC to the other. This process creates a hot side and a cold side on the TEC. A typical application exposes the cold side of the TEC to the object or substance to be cooled and the hot side to a heatsink which dissapates the heat to the environment. A heat exchanger (e.g. Good heatsink or Watercooling system) may be required. Now Lets return to our little adventure. First of all, we need to check the Thermaltakes peltier system, which seems to be ready to work without problems. We can see its peltier, its heatsink fan, and a PCI slot card which controls the wattage on the peltier. At first, we see the peltier and we probably would think about buying something like that, since it seems that cools better than Watercooling and the proce is around 120 dollars. But, wait a minute. At first, we can see that Thermaltakes bundles a very small and it seems that it wont perform as well as a Big Typhoon or a Thermalright heatsink. Then, I think, why does it comes with such a small heatsink if the peltier needs a good cooling system or any other could cause the peltier to get hotter making a disaster in your PC?? So, the maximum wattage in this TT´s product is 73w. Although it seems a lot of energy (similar to a non-overclocked processor) lets continue with the scientific explanation. Rules to consider when using a TEC When using a TEC, there are some things we need to consider before installing it. First of all. The wattage in the TEC is very important, since its going to define, how cooler and hot hotter the peltier would be. There is an easy rule when doing this. The rule, known as Delta-T needs some easy factors -the CPU wattage compsumption -Peltier wattage compsumption -Max teorical temp (more info can be found in Intel and AMD supports/ processor/specs official pages) The formula would be like this. (1-(CPU wattage compsumption/peltier wattage)) x Max teorical temp. Then, lets take an example My PC uses an AMD opteron 146 which works at 1.4v from stock. Its wattage compsumption is 76 watts. Then, the Thermaltalke´s peltier uses a max of 73 watts AMD specified max teorical temp is something about 70ºc, but since we really F.E.A.R. to use it above 55ºC then where using as the max teorical temp. Pentium 4 has a limit of 67ºC or sometimes 69ºC. So, we have. (1-(76/73))x55 (1-(1.041))x55 (-.041)x55 -2.55 As we can see, the result is negative. What does this means? Reading some articles and reviews and users posts we can see that these product is rejected from users. Users usually post that they considered it to work better or they even said it works worst than its older heatsink-fan. Lets imagine that my Opteron worked at 35ºC idle and 50ºC at full load. Using this cooler would increase my temps by 2.5ºC degrees, so thats why negative results are important. If the result from the formula would have been possitive, lets imagine +2.5. Then, i would have gained 2.5ºC from my CPU (which really is not that much). So, thats why users report bad results and commentaries from this product. :frown: But, wait a minute...... Lets continue the adventure Since I was dissapointed from this product, i started to check other peltiers from other brands. I found in www.frozencpu.com some peltiers which seemes to be very inexpensive. http://www.frozencpu.com/scan/se=Water Cooling/se=Peltiers Kits and Coldplates/mp=menu_search.html The first one, using 80 watts which seemed a little bit higher than the TT´s one. The second one, using 226 watts which is almost 3 times bigger than the first one. And the third one, using 437 watts (almost double the 226 watts) So, doing some research i found that 226 watts for a peltier was the most recommended. Before users install a peltier with that amount of wattage, they need to get a very good PSU. Since its not the same adding 80 watts (similar to a 6800 ultra) vs adding a 226 watts peltier (which is like having a PC in idle) or a 437 watts peltier ( as much as a powerfull PC in load). So, there are two possibilities. The first one is buying a very good PSU with a good amperage and at least 500 watts, and the second would be buying a second PSU with just 300 watts and a good amperage just for the peltier. I really recomend the second since the peltier will have its own PSU and if anything goes bad, it wont affect all other components connected to the PSU. So, having a 226 watts peltier will result into this. (1-(67/226))x55 (1-(.296)x55 (.704)x55 38.72 That menas than using a peltier with such wattage and a CPU with such a low wattage would result into a possitive 38ºC degrees reduction!!!! Lets imagine my CPU is running at 40 idle and 55ºC in load. So, with a powerfull 226w peltier, i could have almost subzero temps at idle and less than 20ºC in load. Fantastic right?? So, thats why OCers could use this as a very good option. But, what happens when we overclock? Using my CPU at 3200ghz and 1.6v would increase my 67 watts to 140 watts. I know its a big increase, but its real. then (1-(140/226))x55 (1-(.619)x55 (.381)x55 20.9 Which goes into a 20ºC degrees reduction in temps which are far better than a water cooling system. Imagine your CPU working at 30ºC in load instead of 50ºC ??? But There are other problems when using a peltier. The popularly accepted view of Peltier effect coolers seems to be that they're a one-step way to get super-fast processor speeds on the cheap. Many people think that having a good peltier is enough for having an extreme overclock and so, they dont think on other problems which could happen. First of all: Lets remember the PSU which needs to be really good or even buying another PSU just for the peltier. We have 2 options when using a peltier. 1.- The user buys a pre-built Peltier cooler, with a Peltier element bonded to the bottom of a normal heatsink-and-fan cooler. Then, the user clips it onto the CPU like any other cooler, quite possibly does manage to get the processor running a notch or two faster than would otherwise be possible :dave: , but then either winds things up too far and smokes the cooler and CPU over a couple of days, or gets a flaky computer after a few months because condensation's rusted the motherboard. 2.- The user buys a Peltier element and builds its own peltier cooler which could be very good and give you some magnificent results or it could be a disaster and destroy your PC. Now, as G L pointed 2 posts below this one. Peltiers consume a lot of wattage. Since a lot of CPU´s work well with just 100 watts, then, coolers have been done for that. Even the best coolers, they can dissipate up to 200 watts, but when using a 226 watts or 437 watts peltier, we dont want to disipate the hot air and 400 watts into the case with an air heatsink-fan. So, I truly recommend to use a good watercooling system which can throw the heat outside the case with a big radiator. Since more than 226 is not necesarry (and so, I think it should exist another peltier wattage between 80-226,... maybe 160watts?) we need to use a good watercooling system. I read that the Artic 64 freezer pro can dissipate up to 200 watts, so, 226 is not than far from it. Another problem is the FEARED condensation. As we know, any time you put an object that's cooler than the ambient air temperature in air that's not at zero per cent relative humidity, water can condense on it. Whether water actually will or not's determined by the temperature of the object and the humidity - the higher the relative humidity, the closer to ambient temperature an object can be and still attract condensation. The cold side of a working Peltier is considerably cooler than ambient and so it'll get damp. Over time, with a few high humidity days, it'll get damp enough often enough that the area around the cooler will suffer water-assisted corrosion... and we DO NOT want that. Actually this part was taken from a definition in the Internet but its easily explained. An active-cooled CPU should be not just thoroughly surrounded with waterproofing material, but that material should also insulate it from the surrounding air well enough that condensation on the outside of the waterproofing is negligible. The hot side of a Peltier needs serious cooling, even if the Peltier isn't pumping a lot of heat out of anything, because Peltiers aren't perfectly efficient heat pumps - more heat comes out of the hot side than goes into the cold side. And they don't like overheating. Run a TEC above 80° Centigrade and it will degrade quite quickly; run it above 85° and it can physically fall apart in a few days. Any big chunky CPU cooler can easily dissipate 216 watts without getting so hot that its fan melts or some other spectacular failure occurs. Well, as long as the fan's spinning, it can, anyway. But the best socket air coolers still have thermal resistance up around 0.2° Centigrade per watt. Which means that if they're getting rid of 216 watts, they'll be 43.2° above ambient. Then If the ambient temperature's, say, 25° Centigrade, that puts the heatsink temperature at 68.2°. So a TEC with a 72° ΔT, like this one, should be keeping the CPU below zero! Hurrah! Water cooling+TEC Generally speaking, fan-cooled heatsinks on TECs will give a hot-side temperature at least ten degrees Centigrade higher than you'd expect. A decent water cooler can do a lot better, keeping the hot-side temperature only a few degrees above the temperature of the coolant. Water coolers with a reasonably powerful pump can move heat very effectively. The pump gets the heat from the water jacket on the processor to the radiator; it's the radiator's job to get the heat out of the water and into the air. The hotter the water gets, more heat a given radiator will be able to remove from it. If the ambient temperature's 25° Centigrade and the water goes into a given radiator at 35° and comes out at 30, then, all things being equal, increasing the input water temperature to 45° means it'll only be 35° when it comes out. Increasing the pump power means the CPU water jacket gets a better supply of cool water, but it also means the warm water from the jacket spends less time in the radiator getting cooled. Many cheap water cooling kits seem to come with weedy pumps that really do need to be a bit more powerful, but if you just keep beefing up the pump, you'll strike diminishing returns. If a given water cooling system can't effectively deal with a given heat load, you'll probably need a larger (or second) radiator as well as a better pump. If you do exceed your cooling system's ability to move heat, the results can be disastrous. And, bearing in mind the imperfect thermal contacts involved, don't expect an "80 watt" Peltier to actually be able to effectively cool a CPU that's pumping out 78.3 watts of heat. If a Peltier fails - and they do, when they overheat or when your waterproofing fails and water gets in between the plates - it becomes a pretty good thermal insulator between the CPU and the cooling device. This is bad. Similarly awful things can happen if your CPU cooler fan fails, or your water pump packs it in. To reduce the chance of your CPU becoming a crispy critter, you need a temperature monitor of some sort. Current Intel CPUs all have a temperature sensor built into the CPU, and many motherboards can monitor it. AMD CPUs don't have that sensor, but some motherboards have a sensor under the CPU socket, and many more have at least one temperature probe header on the board somewhere, into which you can plug a thermocouple probe which you can stick to some relevant spot. The BIOS setup for better motherboards has an auto-shutdown temperature, which lets you tell the board to turn the computer off if the CPU temperature hits some set figure. Conclusion So, as we can see, peltiers info is big enough right?? At first, maybe for an engineer or a tecnician, understanding the peltiers effect and so, have the patience to be working and trying and failing and trying again, this work should be normal. But what happends for the big percentage of the users which really dont want to be playing with a 300 US dollar processor?? Then, here is when we can see that many buyers which dont want a back plate for their mobos because they dont want to work and they are scared of big manuals and setups for coolers in which they dont wanna spend more than 5 minutes. And then, for the enthusiasts, even overclocking is a medium knowledge proyect, but when were talking about peltiers, we need to consider a lot of things in which this case I would consider it to be as an extreme, very knowledge proyect. Only those who are ready to fight and work hours trying settings and checking all problems should do this cooling. As we saw above. Many people bought the Thermaltake´s peltier since it seemed really easy to install. Why not?? They just needed to apply the peltier, then the heatsink and then connect the PCI card and thats all. They almost all of them went dissapointed because of the perfomance of the product. So, If youre not prepared to really know and study about physics and this type of cooling which can be so dangerous and complicated, as a lot of users have asked if they can buy a peltier which costs about 5 dollars (because a peltier is really cheap), then, dont do it. But, if you have a peltier build by your own. And its giving good results and it seems very stable. Then, let me know, since I will apreciate you knowledge and there will be nothing more satisfying than making its own peltier system and seeing working it without problems. THE END.....for now?? Here some pics from peltiers in action. Preparing the components Get Ready!! Big Heaters?? Big cooling solutions Santa Claus is coming to town Thats cold! Specially thanks to www.dansdata.com in which as mentioned above, I thougght was a good explanation for technical problems. www.melcor.com which I took as a reference to describe the History of the Peltier effect. And at last, but not least CUSTOM PC which had a simple guide about the formula and which gave me one of my inspirations to do this article. And dont forget Guru3d.com and all the administrators for giving me this space to post.