Top 11 Electronics-Cooling Articles on Heatsinks and Thermodynamics

This article addresses the Seebeck coefficient, a property that determines the performance of thermocouples and Peltier elements. Basically, the Seebeck coefficient is related to the fact that electrons are both carriers of electricity and heat. If a temperature gradient exists over a piece of electrically conductive wire, there is a net diffusion of electrons from the hot end toward the cold end, thereby creating an opposing electric field. In (quasi) equilibrium this field causes a voltage over the wire, the so-called Seebeck voltage.

Heat pipes have been commercially available since the mid 1960s. Only in the past few years, however, has the electronics industry embraced heat pipes as reliable, cost-effective solutions for high-end cooling applications. The purpose of this article is to explain basic heat pipe operation, review key heat pipe design issues, and to discuss current heat pipe electronic cooling applications.

This article discusses thermocouples, the most widely used temperature sensor in test and development work. Accurate temperature measurements can be made at low cost with shop-built probes and ordinary low-level voltmeters.

The need for new cooling techniques is driven by the continuing increases in power dissipation of electronic parts and systems. In many instances standard techniques cannot achieve the required cooling performance due to physical limitations in heat transfer capabilities. These limitations are principally related to the limited thermal conductivity of air for convection and copper for conduction.

Natural convection cooling combined with radiation is what results when a fan is not used in the cooling design to move air. Instead, movement of the air is induced by density differences resulting from the heat dissipated by the electronic components. An obvious advantage of natural convection, or "free" convection as it is sometimes called, is that the expense of incorporating a fan is avoided. Of course the penalty associated with this method of cooling is lower heat transfer coefficients.

Fans can be thought of as low pressure air pumps that utilize power from a motor to output a volumetric flow of air at a given pressure. A propeller converts torque from the motor to increase static pressure across the fan rotor and to increase the kinetic energy of the air particles. The motors are typically permanent split capacitor AC induction motors or brushless DC motors. This article looks at this system in more detail.

Historically, the cost of energy and the cost of the data center power and cooling infrastructure have not been on the radar for most Chief Financial Officers (CFO) and Chief Information Officers (CIO) and have not been considered in TCO (Total Cost of Ownership) models. As a result, almost all of the focus has been on driving down the cost of IT equipment in the data center. This was a reasonable assumption during the 90’s when server power and energy costs were substantially lower. However, power density has been increasing at an alarming rate. During this same period of rapid power growth, server costs have stayed virtually flat and raw performance has increased substantially.

The trend of increasing electronic module power is making it more and more difficult to cool electronic packages with air. As a result there are an increasing number of applications that require the use of forced convection air-cooled heat sinks to control module temperature.

Soldering has been a primary method of establishing mechanical and electrical connections in electronics for many years and will likely be used in this fashion in the future. While there are several physical properties and characteristics of solders that are of interest to the electronics community at large, one of the most significant physical properties to a thermal engineer is thermal conductivity.

With the increase in heat dissipation from microelectronics devices and the reduction in overall form factors, thermal management becomes a more important element of electronic product design.

Thermoelectric coolers are solid state heat pumps used in applications where temperature stabilization, temperature cycling, or cooling below ambient are required. There are many products using thermoelectric coolers. This article discusses the theory behind the thermoelectric cooler, along with the thermal and electrical parameters involved.