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Water Cooling vs Thermoelectric: CoolIT Freezone Elite

Posted May 15, 2009 by Jake in Cooling







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by Jake
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Thermoelectric Cooling

First off, a very brief explanation of thermoelectric cooling. Thermoelectric cooling, also known as Peltier or TEC, consists of a set of plates separated by two semiconducting metals.  The TEC cooler or heater is a solid-state active heat pump which transfers heat from one side of the device to the other side against the temperature gradient (from cold to hot), with consumption of electrical energy. By simply connecting it to a DC voltage over one of the plates, it will cause one side to cool, while the other side gets hot. This creates a transfer effect whereby the "cold" side draws heat away from contacting surfaces and the "hot" side dissipates heat to contacting surfaces.

The effectiveness of the transfer in moving the heat away from the cold side is entirely dependent upon the amount of current provided and how well the heat from the hot side can be removed.  Which means that the more heat dissipated on the “hot side” then the colder it gets on the opposite side and the more heat needs to removed over a small space then the more power it requires.

Literally you can attach the Peltier to anything you want to cool and with a heatsink or any other method of heat dissipating to the "hot" side then you’ve essentially created a bad ass cooling device.  Thermoelectric cooling is usually reserved for more "extreme" enthusiasts, as it often creates difficult problems, one of which is that it can lower temperatures below ambient.  When this occurs, condensation can form on the cool side, and as we all know, condensation and electricity do not mix. So, the difficulty in cooling a CPU is that directly attaching Peltier to the processor is asking for trouble. So if you’re looking for hassle free cooling then this is not the way you want to get involved.

The second problem is the power demand from the TEC; a Peltier is a very power hunger module.  You need a good reliable high end power supply if you want directly connect the TEC to it.   With this approach you only have two choices to run the Peltier at 5v or 12v; you can’t fine tune the voltage to feed TEC to achieve its cooling efficient.  Therefore, you do need to regulate the voltage according to the heat load and your cooling goal.  Regulating voltage to the TEC can be done by having a dedicated PSU, such as Meanwell power supplier to provide a specific voltage to the TEC, or it can be done by PWM (Pulse-with modulation).  On the other hand, controlling voltage this way generates electromagnet which can adversely affect the motherboard transistors or the processor.

Consequently, these two major problems generally give enough reason to stay away from using thermoelectric cooling.  Fortunately however, CoolIT engineers came up a brilliant solution to solve these problems by placing the TEC away from the CPU, thereby avoiding condensation issues. This also creates a positive effect because the TEC doesn’t need to occupy the same space as the CPU, thus allowing a much larger space to be used for the TEC unit.  And since the contacting areas is an integral part of cooling efficiency, the larger area means the overall temperature gradient doesn’t need to be as large.  The advantage of this is the power requirement is then much lower, which ultimately avoids the problems with the aforementioned EMF (electromagnetic field) interference from using PWM for power regulation. In the end, the two major issues are essentailly eliminated, thus making TEC cooling a much more convenient alternative. This is where the CoolIT Freezone Elite comes in.

Since the contacting area is much bigger now, multiple low power TECs can be used in series for increased cooling efficiency and reducing the power demand.   This means you don’t need a dedicated power supply for the Freezone Elite, just a single reliable PSU is good enough to power this cooler. Now, the TEC is away from the CPU so how will it cool the hot, overclocked processors?   That is when liquid chilled cooling come in play; coolant will be used as cooling medium and Peltier as heat exchanger.

As you can see below, the Freezone Elite is a sort of hybrid in a manner of speaking, as it uses liquid cooling technology in conjunction with TEC to avoid the problems traditionally posed by this type of cooling, but achieves the benefits of water cooling to an extent.

So what you end up with is a product that operates like a self-contained water cooling kit, but with thermoelectric cooling enhancements, presumably the best of both worlds. So what’s the catch? Well, there are two main issues: the first is cost; TEC cooling, and specifically the Freezone Elite, does not come cheap as it is more expensive than regular water cooling. However, the bigger problem is a technical consideration: in order for the TEC and Freezone Elite to be very effective, the heat MUST be dissipated quickly, otherwise a heat buildup will occur and cooling efficiency will be lost. There is a thermal limit for each TEC setup as well, so a highly overclocked Quad Core CPU can produce a tremendous amount of heat that becomes increasing difficult to dissipate for a TEC unit. As amazing as the technological strides with the Freezone Elite are, this is simply a limitation that cannot be avoided by current technology.

So, after all that, let’s jump in and get into the product itself.

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