Thermal management (electronics)

All electronic devices and circuitry generate excess heat and thus require thermal management to improve reliability and prevent premature failure.

In cases of extreme low environmental temperatures, it may actually be necessary to heat the electronic components to achieve satisfactory operation.

Together, these two components form a thermal RC circuit with an associated time constant given by the product of R and C. This quantity can be used to calculate the dynamic heat dissipation capability of a device, in an analogous way to the electrical case.

Due to recent technological developments and public interest, the retail heat sink market has reached an all-time high.

Prominent aftermarket heat sink manufacturers include: Aero Cool, Foxconn, Thermalright, Thermaltake, Swiftech, and Zalman.

In the simplest case, this means partially gripping a component using a heavy metal crocodile clip or similar clamp.

On the other hand, electrical components such as magnetic reed switches can malfunction if exposed to higher powered soldering irons, so this practice is still very much in use.

In common use, it is a metal object brought into contact with an electronic component's hot surface—though in most cases, a thin thermal interface material mediates between the two surfaces.

Ideally, heat sinks are made from a good thermal conductor such as silver, gold, copper, or aluminum alloy.

If there is more air being forced into a system than being pumped out (due to an imbalance in the number of fans), this is referred to as a 'positive' airflow, as the pressure inside the unit is higher than outside.

A typical heat pipe consists of sealed hollow tube made of a thermoconductive metal such as copper or aluminium, and a wick to return the working fluid from the evaporator to the condenser.

The most common heat pipe for electronics thermal management has a copper envelope and wick, with water as the working fluid.

It has a relatively low efficiency, so thermoelectric cooling is generally used for electronic devices, such as infra-red sensors, that need to operate at temperatures below ambient.

A synthetic jet is produced by a continual flow of vortices that are formed by alternating brief ejection and suction of air across an opening such that the net mass flux is zero.

The basic principle has been understood for some time but only in recent years have seen developments in the design and manufacture of EFA devices that may allow them to find practical and economical applications, such as in micro-cooling of electronics components.

For example, funded by the U.S. Department of Defense, research has been underway using high-power density gallium nitride transistors with synthetic diamonds as thermal conductors.

[citation needed] Thermal simulations give engineers a visual representation of the temperature and airflow inside the equipment.

Most thermal simulation software uses Computational fluid dynamics techniques to predict temperature and airflow of an electronics system.

There is a constant pressure to reduce power requirements, system weight and cost parts, without compromising performance or reliability.

Thermal simulation allows experimentation with optimisation, such as modifying heatsink geometry or reducing fan speeds in a virtual environment, which is faster, cheaper and safer than physical experiment and measurement.

The device is powered up, perhaps inside an environmental chamber, and temperatures of the critical parts of the system are measured using sensors such as thermocouples.

A change to the design of a PCB or enclosure part may be required to fix the issue, which will take time and cost a significant amount of money.

There are a wide range of software tools that are designed for thermal simulation of electronics include 6SigmaET, Ansys' IcePak and Mentor Graphics' FloTHERM.

For example, most mature central offices have limited space available for large air duct installations that are required for cooling high heat density equipment rooms.

Furthermore, steep temperature gradients develop quickly should a cooling outage occur; this has been well documented through computer modeling and direct measurements and observations.

In a recent case, telecommunications equipment in a major central office was overheated, and critical services were interrupted by a complete cooling shut down initiated by a false smoke alarm.

HRTs take into account physical limitations of the environment and environmental baseline criteria, including the supply airflow capacity, air diffusion into the equipment space, and air-distribution/equipment interactions.

In addition to being used for developing the HRTs, the EC Classification can be used to show compliance on product sheets, provide internal design specifications, or specify requirements in purchase orders.

The main purpose of RC-Classes is to provide a logical classification and description of legacy and non-legacy room-cooling schemes or protocols in the central office environment.