How Does a CPU Cooling Fan Work?
The CPU is the brain of any computer system, handling millions of calculations every second. All that computer power generates heat, though – enough to disable the delicate electronics. A CPU cooling fan is necessary to dissipate that heat, and maintaining your computers’ cooling systems can increase their lives and reduce the chance of damage to important business systems.
The basic thermodynamic principle behind CPU cooling is convection. A hot object transfers some of that heat to the air molecules near its surface, cooling slightly in the process. If the air is moving, then these heated molecules will float away, allowing cooler air to replace them and absorb more heat. Using a fan forces the air to move, providing a constant stream of cooler air to absorb heat from the object and significantly increasing the rate of cooling.
Simply passing air over a CPU will not be sufficient to cool it, due to the high temperatures these chips can reach. A heat sink is a block of aluminum or another metal designed to conduct heat. The bottom of the heat sink is flat, to allow for maximum contact with the CPU, and the upper surface contains a number of narrow fins with air channels between them. This greatly increases the surface area available for convective cooling, and increases the amount of heat the CPU fan can dissipate as it blows air through these channels.
Most modern CPU fans have a variable speed control. Sensors in the motherboard monitor the CPU temperature as the computer runs, and direct the fan to speed up or slow down in response to activity and load. Depending on the manufacturer of your CPU and cooler, the fan may stop during idle periods, only spinning up in the face of intensive calculations. You should hear your fan spin up when running graphically intensive programs, such as computer aided design tools or video rendering programs. If you hear a CPU fan running at high speeds when the computer is performing less intensive tasks like spreadsheet calculations or word processing, it could be indicative of a problem or rogue malware running on your system.
You can keep your CPU cooling fan working at maximum efficiency by following a few steps. You should regularly clean your fan and heat sink using a compressed air duster to prevent buildups that might trap heat and damage fan motors and bearings. Make sure you switch off your computer and leave it off for a few minutes to cool down before dusting. You should also try to maximize airflow through computer cases by ensuring intakes and vents remain clear and unobstructed, and avoiding tangles of cables inside the case that could impede airflow. Spending a few minutes maintaining your CPU cooling system could mean the difference between extending the life of valuable company hardware and having to replace burned-out systems early.
Milton Kazmeyer has worked in the insurance, financial and manufacturing fields and also served as a federal contractor. He began his writing career in 2007 and now works full-time as a writer and transcriptionist. His primary fields of expertise include computers, astronomy, alternative energy sources and the environment.