Where I live now, there are no ceiling fans, so getting the air circulating can be a bit tough.

I wanted some sort of fan I could put in the window, and it would act as some sort of exhaust fan,

as in blowing the air outward, creating negative pressure inside.

Then, I would have another window open somewhere else, and since that would be the easiest place to pull from, fresh air would come rushing in.

If you're asking yourself, why is Josh doing this, I had purchased an air quality monitor,

and I noticed the CO2 levels were getting high, and I wanted to keep them lower.

Air quality is a tangent for another time, but that's why I was doing it.

So I did some searching, and there were some pre-made fans that you could buy and stick them in a window,

but they just didn't move enough air.

Then I stumbled across one on a blog that had one built out of computer fans.

Essentially, you take six 120mm computer fans, you get two...

...new shh!

...

strips of C-channel, which is a long metal strip bent at a 90 degree angle, creating an L,

but it's called C-channel, and you attach the fans between the C-channel so you end up with

a row of fans stuck together. You then wire the fans together, connect them to a motor speed

controller, and then you wire that to a wall power supply. Depending on the fans you use,

you end up with something that can move around 500 to 600 cubic feet of air per minute,

which is impressive. It means you can turn over the air in a home pretty quick. And why this random

story? Because while I'm using computer fans to cycle fresh air, they are also used to keep

computers cool. If you are listening to this on a laptop or desktop computer, then you might hear

a fan spinning now. The piece of your computer that keeps it from overheating on this episode of In The

C-channel. The wrong thing to do is just go out and buy a computer and then learn about it. You

learn, but you'll learn a lot of things that maybe you didn't want to learn. A computer that you buy

today will likely be obsolete six months from now, and there's not a dang thing that you can do about

it. My name is Josh, and I'm able to keep this podcast independent and advertisement free because

of support from listeners like you. If you are finding value in what I'm doing here, consider

becoming a paid supporter at members.sideofburritos.com. And as a thank you, members get early

access to new videos, ad-free versions of everything, bonus content, and access to a live

monthly Q&A. Thanks for considering. Now let's get back to the show. Electronic components naturally

generate heat when in use. As electric current flows through circuits, the electrical energy is

partially converted into heat due to resistance in the materials. Moving electrons collide with

atoms in the conductor, causing the atoms to vibrate fast.

that vibration is released as heat. This phenomenon is known as joule heating. The

higher the current draw or the greater the resistance in a component, the more heat gets

produced. This waste heat isn't just a trivial byproduct. If it isn't managed, it can reduce

performance or even damage the device. Even tiny microchips can get surprisingly hot due to the

dense maze of transistors inside them, so managing heat is a critical part of electronics design.

Engineers must use cooling mechanisms to carry excess heat away, ensuring devices run efficiently

and don't overheat or throttle their performance. In desktop and laptop PCs, the most common cooling

method is air cooling, which uses metal heat sinks attached to hot components and fans to move air.

You can think of a heat sink as a car's radiator. Just as a radiator draws heat away from the car's

engine, a heat sink...

draws heat away from the computer's processor.

The heat sink is usually made from a thermally conductive material like aluminum or copper

and has many thin fins to increase surface area.

Heat from the CPU or GPU flows into these fins.

A fan attached to the heat sink then blows air through the fins, carrying the heat away

into the case air and ultimately out of the computer.

This combination of a finned heat sink and fan is simple but very effective.

Most computer cases are built with multiple fans.

Typically, cooler air is pulled from the front or bottom and warmer air is expelled at the

back or top.

This airflow carries heat away from components like the CPU, GPU, and power supply.

Keeping the inside of the case free of dust and arranging cables neatly can further improve

air circulation.

For more demanding systems or enthusiasts aiming to lower temperature and quieter operations,

liquid cooling is a popular step up. Liquid cooling, often using water or special coolant

fluids, can absorb and transfer heat more efficiently than air because water has a high

thermal conductivity. The basic idea is similar to a car's cooling system. A pump circulates

coolant through tubes to components and then out to a radiator, where fans dissipate the heat

into the air. In a PC, a water block, which is a specialized metal plate with internal channels,

is attached to the hot components. The coolant flows through the block, picking up heat from the CPU,

and then travels to a radiator, mounted usually on the case wall, where fans cool down the liquid.

The cooled liquid then loops back to the block in a continuous cycle. This method can carry away

a lot of heat quickly and often allows high performance CPUs and GPUs to run cooler under

heavy load compared to air cooling. For those who really

want to get creative or just have fun tinkering, there are also some extreme cooling methods out

there. One famous example is submerging an entire PC's components into mineral oil. Mineral oil is

a clear, non-conductive liquid, meaning electronics can run while fully submerged in it without

shorting out. In a typical setup, the motherboard and other components, except drives, are placed

inside a glass tank filled with purified mineral oil, almost like an aquarium for your PC. As the

computer runs, heat spreads into the oil, which gently convects the warmth away from the components.

To get rid of the heat continuously, the oil is often pumped through a radiator, just like with

water cooling, to transfer the heat to the air outside the tank. The submersion technique is mostly

a DIY novelty and conversation piece, rather than a practical everyday solution.

Now when it comes to cooling a smartphone or tablet, it's a whole different challenge.

Unlike a roomy PC tower, a phone has no space for bulky heatsinks or fans, which means that mobile devices rely almost entirely on passive cooling.

This means smartphones must dissipate heat using internal design and materials without any fans blowing inside.

Essentially, the phone's structure itself acts as a heatsink.

You might have noticed this when you're doing something intensive on your phone and the device begins to feel warmer in your hand.

The heat generated by the CPU, GPU, and other components is spread out and conducted to the phone's outer casing or other internal layers where it can radiate away safely.

Manufacturers use techniques like metal frames, graphite sheets, thermal paste, and tiny heat pipes or vapor chambers to channel heat away from the chips.

Even with these clever, passive cooling methods, mobile devices have built-in safety mechanisms for when things get too hot.

If you've ever noticed your phone getting very warm...

...

and then seeming to slow down, dim its screen, or go into dark mode,

that's likely thermal throttling in action.

When the internal temperature crosses a certain threshold,

the phone software will automatically dial back the CPU's speed,

and sometimes other features, to reduce heat generation.

Now imagine scaling things up from a single PC

to hundreds or thousands of computers packed together,

and that's what happens in server rooms and data centers.

These facilities are the backbone of the internet and cloud services,

filled with racks upon racks of servers running 24-7.

All those servers running non-stop means a lot of heat is being generated in one place.

Traditional data centers use massive air conditioning and ventilation systems

to keep temperatures in check, but they also employ clever layout strategies.

A common approach is hot aisle, cold aisle containment.

Servers are arranged in a row so that the fronts of the servers

可以 Lots of headquarters cells be added in a row so that the nodes are boiling out of the VOC system that releases all minus sizeOU from 3-7%

And so it looks tough, but it does notピned with four-8% lower than any dataж

which draw in cool air, all face each other across an aisle,

and then the backs of the servers, where hot air blows out, face each other on a different aisle.

By separating the cold aisle, the intake side, from the hot aisle, the exhaust side,

with physical barriers or partitions, the hot air coming out of the server

is contained and directed away to AC return vents,

while the cold air from the AC is delivered directly to the server's intakes.

When arranged this way, the hot and cold air don't immediately mix,

making cooling much more efficient.

All computing devices, whether it's your smartphone, your gaming PC, or a giant cloud server,

all face the same basic battle against heat.

In the Shell is written, researched, and recorded by me, the fan-cooled podcaster.

If you are listening in an app that lets you rate shows, please take a minute to rate this one.

I would truly appreciate it.

The other day I was cleaning out the fans on my computer,

and I found a spider inside it. I guess it was trying to make a website.

That's it. Take care, and I'll see you next time.