Proper desktop computer case cooling

Computer Case Cooling

With today’s computer chips getting smaller and more powerful, heat build-up becomes a primary concern. It is no wonder that computer cases have provisions to enable installation of fans of varying sizes and features. But what are the essential things to consider in achieving proper cooling? Be it that you a novice DIY rigger or a pro-extreme gaming rig enthusiast, some information that’ll be shared here would be of great help. For those who buy their computer all assembled or branded ones, read on please, as some sections of this post cover some issues you might have about cooling.
Important terminologies
Fans used for computer cooling, whether for an air-cooled setup or water-looped system, are simply used to move air. Air absorbs heat, which changes its density and hence lighter. So, even without a fan hot air will move or rise. This is called free convection. On the other hand, which is a particular interest to this post, forced convection is the movement of air by the application of the mechanical action of a fan. The most common specs that are of primary importance for a fan are its volumetric capacity rate, expressed in CFM (cubic feet per minute), and static pressure. CFM is a fan’s ability to move a certain amount (or volume) of air in a minute. Static pressure is a measure of a fan’s strength to move or push a corresponding CFM of air.

Air balance – what is it and why it’s important

Imagine a typical computer case as an occupied room, with the important components like CPU, motherboard, memory, video card and harddisk as its occupants. Through time, the heat generated by these “occupants” would saturate the air inside the “room” and becomes very uncomfortable for the “occupants”. By default, CPU’s when installed have a heatsink and a fan, much the same as with the video cards. But all these fans ever do is blow air into the processor, using the air in its immediate vicinity. However, that air is already hot and would not effectively absorb the heat generated by these components. This is where the concept of air balance plays an important role.

The rate of air change inside the computer case should be such that it can sufficiently provide “new” or fresh air (cooler air) so as heat can be absorbed properly. Likewise, this warm air should be effectively discharged out of the case in pretty much the same rate or higher. This can be achieved if an intake and exhaust (outtake) fan are correctly installed in the case (please see figure 1). Ideally, exhaust fan(s) should have enough CFM capacity to effectively discharge the warm air out of the case, while the intake fan(s) should provide enough fresh air – in almost balanced quantity.

Air flow direction – do’s and don’t’s

As a rule of thumb, and to avoid confusion, computer case fans follow an unwritten convention that would show the air flow direction once they are on (see figure 2). With that known, installing the fans in the case would be easy – whether used for intake or exhaust.

It's a common mistake to improperly install fans. Doing so, could cause fans working against each other resulting in disrupted air flow direction. This is important even with installing after market CPU cooling fans. The fan direction for its exhaust should not work against the case fans installed either at the rear or on top of the case.

The arrow shows the direction of the air flow - this is a correct setup

By and large, keeping this fan installation basics will greatly aid in managing your computer case temperatures and all its internal components as well. Happy computing!