What is the Difference Between Active and Passive Cooling?

active passive cooling
Thermal problems are very common in product design, especially electronics. Designing efficient printed circuit boards (PCBs) that don’t overheat or energy-efficient microprocessors is challenging.

Architectural design is also an industry that needs to make great efforts for thermal management, whether we’re talking about server rooms, office buildings or private houses.

To cope with these problems, engineers use different cooling systems, which fall under the active and passive cooling techniques. But what is the difference between them?

Passive Cooling

Low costs and energy-efficiency make passive cooling techniques worth the time, both in systems design such as electronics (laptops, television sets, boxes etc.) and buildings.

Passive cooling relies on a heat spreader or a heat sink to maximize the radiation and convection heat transfer modes for achieving high levels of natural convection and heat dissipation. This leads to proper cooling in products and thermal comfort in homes or office buildings; very known here are passive houses.

In architectural design, the natural resources like wink or soil are used as heat sinks to absorb or dissipate heat.

Passive thermal management relies on heat sinks, heat spreaders, heat pipes or thermal interface materials (TIM).

Active Cooling

Active cooling refers to cooling technologies that must introduce energy with the help of an external device to enhance heat transfer. Through active cooling, the rate of fluid flow increases during convection, which dramatically increases the rate of heat removal.

Active cooling options are forced air through a fan or blower, forced liquid and thermoelectric coolers (TECs). Fans are used when natural convection is insufficient to remove heat. Common in electronics, they can be integrated in the computer case or attached to CPUs, hard drives or chipsets.

The main disadvantage of active thermal management is that is implies the use of electricity and higher costs, compared to passive cooling.

Why Use a Thermal Analysis Software?

Early in the design phase, a thermal analysis software can be used to virtually test fans, blowers, heat sinks, chips, PCBs and even server rooms and buildings, for a better thermal management.

Performing thermal analyses, designers can predict the airflow, temperature distribution and heat transfer in systems long before creating physical prototypes and with significantly reduced costs. In the project, a heat sink design is analyzed through conjugate heat transfer simulation, with the purpose of optimizing it and ensure proper cooling.

But thermal analysis software can also help you decide between active and passive cooling techniques. This workshop recording and its step-by-step tutorial help you compare active cooling and passive cooling of a Raspberry-Pi housing by creating a thermal simulation project. Access to the SimScale platform  to follow this tutorial is free. Create an account here.

SimScale is the world's first cloud-based simulation platform, enabling you to perform CFD, FEA, or thermal analyses. Sign up for the 14-day free trial and join the community of 70 000 engineers and designers. No payment data required.