iXBT Labs - Computer Hardware in Detail






Peltier Coolers

October 26, 2000

<< Previous page

     Next page >>

The work of modern efficient electronic devices dissipates a lot of heat, especially while overclocking. Effective work of such components require adequate cooling. As a rule, we use fan based coolers.

The reliability and performance of them grow constantly due to construction improving, usage of the latest technologies for sensor development. However, not so long ago there appeared new-based cooling devices - semiconductor coolers which utilize the Peltier effect.

Peltier coolers containing specific semiconductor thermoelectric modules have the widest perspective in the market for cooling devices.

Thanks to their unique heat and operational characteristics, Peltier modules allow to reach the required cooling of computer components without huge technical problems and finance expenditure. They are quite compact, convenient, reliable and efficient.

In the systems, elements of which are operated in the tough temperature modes (i.e. in case of overclocking), Peltier modules are of great interest.

Peltier modules

Peltier coolers feature thermoelectric coolers based on the Peltier effect. The given effect was named after a French watchmaker Jean Charles Athanase Peltier (1785-1845.), who discovered it in 1834.

If you put a drop of water in the hollow on the joint of 2 semiconductors Sb and Bi, and switch on the current, the drop would freeze (with the reverse direction of the current the drop would melt). This is how Peltier effect works.

Unlike the Joule heat which is proportional to the current strength squared (Q = R*I*I*t), the Peltier is proportional to the current strength and changes the sign (-/+) if the current changes the direction. The Peltier heat equals:

Qp = P*q

where q = I*t, P is a Peltier factor that depends on contacting materials and temperature.

Peltier heat is considered positive in case of dissipation, and negative in case of absorption.

Fig.1. The scheme of the experiment of Peltier heat measuring, Cu, Bi.

In this case the Joule heat in both calorimeters is the same (since R = R(Cu)+R(Bi)). But the Peltier heat differs in the sign. So, this experiment allows to calculate the Peltier factor.

In the table below you can see some Peltier factors for different pairs of metals.

Peltier factors for different metal pairs
Fe-constantan Cu-Ni Pb-constantan
T, K P, mV T, K P, mV T, K P, mV
273 13.0 292 8.0 293 8.7
299 15.0 328 9.0 383 11.8
403 19.0 478 10.3 508 16.0
513 26.0 563 8.6 578 18.7
593 34.0 613 8,0 633 20.6
833 52.0 718 10.0 713 23.4

Usually, a Peltier factor is calculated this way:

P = a*T

Where P is the Peltier factor, a is the Tomson factor, T is the absolute temperature.

In theory, the Peltier effect is explained the following way: electrons speed up or slow down under the influence of contact potential difference. In the first case the kinetic energy of the electrons increases, and then, turns into heat. In the second case the kinetic energy decreases and the joint temperature falls down.

In case of usage of semiconductors of p- and n- types the effect becomes more vivid. On the scheme you can see how it works.


Fig.2. p- and n-type semiconductors in thermoelectric coolers

Combination of many pairs of p- and n-semiconductors allows to create cooling units - Peltier modules of relatively high power (see the scheme below).

Fig.3. Structure of a Peltier module

A Peltier module consists of semiconductors mounted successively, which form p-n- and n-p-junctions. Each junction has a thermal contact with heatsinks. When switching on the current of the definite polarity, there forms a temperature difference between the heatsinks: one of them warms up and works as a heatsink, the other works as a cooler.

Fig.4. A Peltier module

A typical module provides a temperature difference of several tens degrees Celsius. With forced cooling of the hot heatsink, the second one can reach the temperatures below 0 Celsius. For more temperature difference the cascade connection is used.

Fig.5. An example of cascade connection of Peltier modules

The cooling devices based on Peltier modules are often called active Peltier coolers or Peltier coolers.

Peltier module's power depends on its size. The modules of low power might not be efficient enough. But the usage of the modules of too high power might cause moisture condensation, what is dangerous for electronic circuits. The distance between conductors on the modern printed circuit boards constitutes parts of a millimeter. Nevertheless, they were powerful Peltier modules and additional cooling systems which helped KryoTech and AMD companies to overclock AMD processors up to 1 GHz. We should notice here, that the systems work was stable and reliable enough. Similar experiments were made with Intel Celeron, Pentium II, Pentium III, which achieved tremendous performance growth.

We should point out that Peltier modules dissipates a lot of heat. That's why it's necessary to use not only a powerful fan in the cooler, but also other different fans inside the case.

Fig.6. An outward appearance of a cooler with a Peltier module

The information on Peltier modules, coolers and their test results you can find on the following sites:

Write a comment below. No registration needed!

Next page >>

Article navigation:

Page 1: Introduction, Peltier modules

Page 2: Features, moisture condensation, examples

blog comments powered by Disqus

  Most Popular Reviews More    RSS  

AMD Phenom II X4 955, Phenom II X4 960T, Phenom II X6 1075T, and Intel Pentium G2120, Core i3-3220, Core i5-3330 Processors

Comparing old, cheap solutions from AMD with new, budget offerings from Intel.
February 1, 2013 · Processor Roundups

Inno3D GeForce GTX 670 iChill, Inno3D GeForce GTX 660 Ti Graphics Cards

A couple of mid-range adapters with original cooling systems.
January 30, 2013 · Video cards: NVIDIA GPUs

Creative Sound Blaster X-Fi Surround 5.1

An external X-Fi solution in tests.
September 9, 2008 · Sound Cards

AMD FX-8350 Processor

The first worthwhile Piledriver CPU.
September 11, 2012 · Processors: AMD

Consumed Power, Energy Consumption: Ivy Bridge vs. Sandy Bridge

Trying out the new method.
September 18, 2012 · Processors: Intel
  Latest Reviews More    RSS  

i3DSpeed, September 2013

Retested all graphics cards with the new drivers.
Oct 18, 2013 · 3Digests

i3DSpeed, August 2013

Added new benchmarks: BioShock Infinite and Metro: Last Light.
Sep 06, 2013 · 3Digests

i3DSpeed, July 2013

Added the test results of NVIDIA GeForce GTX 760 and AMD Radeon HD 7730.
Aug 05, 2013 · 3Digests

Gainward GeForce GTX 650 Ti BOOST 2GB Golden Sample Graphics Card

An excellent hybrid of GeForce GTX 650 Ti and GeForce GTX 660.
Jun 24, 2013 · Video cards: NVIDIA GPUs

i3DSpeed, May 2013

Added the test results of NVIDIA GeForce GTX 770/780.
Jun 03, 2013 · 3Digests
  Latest News More    RSS  

Platform  ·  Video  ·  Multimedia  ·  Mobile  ·  Other  ||  About us & Privacy policy  ·  Twitter  ·  Facebook

Copyright © Byrds Research & Publishing, Ltd., 1997–2011. All rights reserved.