model of liquid cooling system

As I sit in front of my air conditioner, looking up weather forecasts of extreme heat for most of the United States, I started to wonder about how computers keep themselves cool.

Let’s look at desktops. Why would anyone need more than a simple fan exhaust? If you are just checking your e-mails and reading articles on Wikipedia, you will not need to worry about anything more than that. Increased power consumption equates to more heat being produced. Generally, the greater the tasks you are asking your PC to run, the cooler you will need your machine to be. This is a vital concern when it comes to professional gamers’ systems, for example, which are expected to run at peak performance at all times. This is why a lot of gamers go to extreme lengths to keep their desktops cool.

There are two main routes when looking to cool your machine: air cooling and liquid cooling, the later being more involved than the first. An air cooling setup is the basic approach and consists of a heatsink, heat pipes, and a fan. Cool air from inside the case lifts heat from the various components, assisted by the heatsink and pipes—if installed, and whisks the heat produced out of the machine through a fan. For most of us, this type of cooling is fine and assuming the parts never fail, we will probably never even give this operation a second thought.

air cooling systems - unit mounted fans

For others, such as the aforementioned PC gamers, a liquid cooling system is more adequate to get the job done. Liquid cooling operates using a type of coolant, often distilled water, which is cooled by a radiator to which the hot air from the components is sent for cooling. Using a coolant offers a much higher heat capacity, which allows liquid coolers to maintain consistently lower temperatures for the components over air coolers. The coolant’s reservoir determines how much cooling can be done with a greater capacity resulting in cooler temperatures.

There are many variations to liquid cooling. One of the more extreme is the submerged cooling setup, in which nearly all hardware rests in a liquid coolant for a greater degree of cooling. All of these options are more involved and more expensive than air cooling solutions.

This is all fine and good for desktop PCs but what about larger operations such as server farms and data centers? The options are essentially the same but with a few tricks employed to help the cooling of the machines, primarily the use of aisle containment.

The idea behind aisle containment is fairly simple; containment seeks to separate (I.e. contain) the heated air and the cooler air from one another. This is typically accomplished by pairing rows of cabinets in such a way that cool air can be easily pumped through air intakes and warm air can be returned to chillers without mixing the two. An easy way to do this is to place the exhausts from the machines that fan out the warmed air facing each other in alternating aisles. This keeps the heat in one aisle while the next one needs no additional cooling.

diagram of cold aisle contaiment airflow

There are two types of aisle containment: hot aisle containment and cold aisle containment. The cold aisle containment model often uses doors or partitions to cool the aisle and keep it that way. This tends to be less expensive because, for the most part, the layout of the floor plan often is already suited for this type of cooling.

Hot aisle containment frequently uses ductwork or vents (sometimes located in raised floors) to usher in chilled air from air conditioning unit and return it to be cooled. This method can be expensive but tends to be the more efficient of the two.

So, there you go: a basic guide to keeping your machines as cool as you during this long hot summer.