Heat Sink

What is a Heat Sink?

A heat sink is a hardware component that is attached to a critical digital or electromechanical component to prevent it from overheating. The primary purpose of a heat sink is to absorb the heat the critical component generates and disperse it.

In computing, heat sinks prevent processors from reaching temperatures that could cause malfunctions or physical damage. Most of the time, heat sinks are installed during the manufacturing process.

However, if you are building a computer from scratch or are installing a more powerful central processing unit (CPU) or graphics processing unit (GPU) on a gaming PC or crypto mining rig, you will need to purchase a heat sink and install it yourself.

Techopedia Explains the Heat Sink Meaning

Heat sink definitions often make a distinction between active and passive heat sinks.

Passive heat sinks do not have moving parts. They rely on the properties of thermodynamics to dissipate heat naturally. This type of heat sink is often pre-installed and used to keep tablets and smartphones from overheating.

In contrast, active heat sinks include a fan or pump that moves air or liquid across the heat sink’s surface to dissipate heat. This type of heat sink is used more often to keep desktop computers, servers, gaming PCs, and electromechanical devices used in manufacturing from overheating.

How Heat Sinks Work

Technically, heat sinks use conduction to absorb heat and convection to dispense the heat into the surrounding environment.

Essentially, the base plate absorbs heat from the component it is attached to through conduction, and the fins dissipate the heat into the surrounding air through convection.

Active heat sinks include a fan to move more air through the heat sink’s fins and increase the heat dissipation rate.

Key Components of a Heat Sink

Base plates, fins, and mounting mechanisms are the three key components of both passive and active heat sinks.

Types of Heat Sinks

While most passive and active heat sinks use air to dissipate heat, some types of more sophisticated (and expensive) heat sink designs use liquid cooling and heat pipes.

This type of heat sink is more expensive, but it offers several advantages over air cooling, including higher thermal conductivity, more efficient heat transfer, and the ability to dissipate heat over a larger area.

Liquid-cooled heat sinks are typically used to improve heat dissipation for high-performance computing applications and overclocked operating systems (OS).

Essentially, a liquid coolant (such as water) absorbs heat from the heat sink’s base plate and is passed through a radiator. The radiator functions much like a traditional air-cooled heat sink, using extensive fins to increase the surface area and dissipate heat into the air.

Some types of liquid-cooled heat sink designs also include heat pipes.

Heat pipes are sealed, hollow tubes filled with fluid. One end of a heat pipe is located near the heat sink’s base, and the other end is located near the heat radiator’s fins.

As heat from the source comes into contact with a heat pipe, the fluid absorbs the heat and turns to vapor. The hot vapor rises in the tube until it reaches the fins, where condensation turns it back into a liquid. The liquid then flows back towards the warmer end of the heat pipe and begins the cooling process again.

Factors to Consider When Choosing a Heat Sink

The choice of heat sink depends on factors such as the required level of thermal conductivity and heat load management.

Thermal conductivity describes a material’s ability to conduct heat. Most heat sinks use aluminum or copper, both of which have relatively high thermal conductivity compared to other materials.

Aluminum is commonly used for passive heat sinks. It is inexpensive, readily available, and can be easily manipulated to accommodate different types of fin structures.

Copper is also easy to use, but it’s more expensive. Copper has higher thermal conductivity and is a better choice for applications that need to maximize heat transfer efficiency.

Many heat sinks use a combination of copper and aluminum components to obtain the benefits of copper at a lower cost. For example, the base plate may be made of copper for its superior thermal conductivity, while the fins are made of aluminum for cost savings and weight reduction.

What Affects Heat Sink Performance

The heat sink’s surface area and the spacing between fins will affect its ability to dissipate heat into the surrounding environment.

Too much spacing will allow heated air to bypass the heat sink, while too little spacing can impede airflow and hinder heat dissipation.

Ventilation and airflow management within the heat sink’s housing can also impact performance. Factors such as airflow direction, obstructions in the airflow path, and fan speed can affect cooling effectiveness.

How to Install a Heat Sink

1. When you are installing an aftermarket heat sink on a CPU or GPU, the first thing you will need to do is apply a thin layer of thermal compound (also called thermal paste) on top of the processor. This will allow the heat sink to absorb heat.
2. The next step is to attach the heat sink to the processor and secure it with mounting mechanisms. Heat sinks require close contact, so proper alignment with the heat-producing component is important.

If you are installing an active heat sink, you will also need to connect the heat sink’s fan with the CPU fan header on the computer’s motherboard. This will allow the motherboard to monitor temperatures and adjust fan speeds accordingly for optimal cooling and noise management.

Applications of Heat Sinks

Heat sinks are often used in computing to reduce the heat generated by processors, but the principles of heat transfer can be applied to many other applications.

Here are some other ways heat sinks are used:

Heat Sink Pros and Cons

Like any engineering solution, heat sinks have both pros and cons.

For example, aftermarket heat sinks are highly effective at dissipating heat away from electronic or mechanical components, but they need to be installed properly to prevent overheating.

Here are some of the other pros and cons of purchasing and installing aftermarket heat sinks:

The Bottom Line

Heat sinks prevent processors on electronic devices and components in many electromechanical devices from overheating. They use conduction to absorb heat and convection to dissipate it into the surrounding environment.

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