As electronics use up more power and emit more heat, we are being forced to find better cooling systems, and it’s a hard process. We can improve our standard heatsink/fan cooling systems with liquid metal or better thermal pastes, or we can upgrade to liquid cooling altogether, but these improvements still can’t improve how fast the heat moves from the chips to the cooling system. That’s where a vapor chamber comes in! They can serve as a great way to transfer heat to other cooling components or they can serve as a whole cooling system in itself.
Today, we’ll learn more about the cool nature of vapor chambers by tackling their history, benefits, and drawbacks over other cooling systems, and we’ll also talk about where we can put these cooling systems and whether it’s worth it to add a vapor chamber to your PC and other devices, let’s get started!
What Are Vapor Chambers and Where Did They Come From?
A vapor chamber sounds alien, doesn’t it? But it’s simpler than you think. A vapor chamber is a type of heat transfer device that uses the evaporation of a liquid to gas to transfer heat from one place to another, kind of like a heat pipe. In fact, it is a variation of heat pipes, but we’ll explain the differences in better detail later.
Vapor chambers and heat pipes also have a cool history (pun intended); heat pipes were patented back in 1942, but there are no uses for them at the time. The first notable use of heat pipes is when NASA used them for heat management on satellites in the late 1960s. Going into the 70s people started implementing heat pipes into boilers and HVAC systems. Then electronic companies also started to use heat pipes to cool down transistors in the 80s.
Vapor chambers are a variation of the heat pipe, and it’s made to solve and improve a problem that heat pipes made, and that is the fact that heat pipes can only transfer heat linearly, thus vapor chambers are also known as planar heat pipes or heat spreaders. Now let’s talk about how it works.
How Vapor Chamber and Heat Pipes Work
When it comes to knowing how vapor chambers work, we must know how heat moves from one place to another and how heat pipes work first.
Heat transfer can be done through conduction, convection, and radiation.
- Conduction is the direct heat transfer between atom to atom, you can see this most often on metals and other solids.
- Convection is the movement of heat through liquid or gas, and we can see this most often in fluids.
- Lastly, radiation is the transfer of heat or energy through electromagnetic waves, we can observe this through how the sun heats our planet or how microwave ovens heat our food. Radiation is not commonly observed in electronic cooling systems though.
Heat pipes are made of three things: a vapor chamber, a wick that holds and transports the liquid, and an outer shell to seal it all up and keep everything inside under a vacuum, commonly a copper tube, but other materials are used for other working temperatures and applications.
So how does it work?
It all begins with the hot side of a heat pipe, or the side that’s attached to the heat source, as it’s being heated up, the liquid within the wick (usually plain old water or some alcohol mix) is also getting hot and after a while, it’ll boil, and turn into a hot vapor which then goes through the vapor chamber and it makes its way to the other side together with the heat it carries. And yes, the liquid will boil and vaporize at a much lower temperature since the insides of a heat pipe are under a vacuum.
The other side of the heat pipe is the cold side, it’s being constantly cooled by heatsinks, fans, or a combination of both. So when the vapor makes it to the cold side, it’ll cool down and condense back into a liquid which is then absorbed by the wick once again, and thanks to capillary action, the fluid makes its way back into the hot side for it to vaporize once again, and that’s basically it!
Vapor chambers work the same way that heat pipes do that’s why they’re called planar heat pipes, but instead of being a pipe, it’s a sandwich of metals. The exterior is also commonly made with copper or other metal, the insides are also lined with a wick, and at the core of it is the vapor chamber, which now has structural support to prevent itself from collapsing. It works the same way as well! It’s a cycle of the fluid turning into vapor which makes its way to the cool side to be condensed back into a liquid again.
Benefits of Vapor Chambers Over Other Cooling Components
Now that we know how these different cooling components work, what are the benefits of vapor chambers or heat pipes over other cooling components?
Early and simple cooling systems consist of heatsinks and fans, which are essentially a simple combination of conduction and convection; the heat is extracted from the component to the heatsink’s fins and convection takes away the heat from the fins usually accompanied by a fan to make it more effective.
Heatsinks and fans can get the job done, but as electronic components got more powerful and started emitting more heat, they just can’t keep up anymore, and that’s the reason why heat pipes are made!
Heat pipes transfer heat more efficiently than simply relying on a metal’s conductive properties. But then again, there is still room to improve since heat pipes can only transfer heat linearly thus limiting the number of components it can cool to a single area.
Now, we got the vapor chambers, or planar heat pipes, as we established, it works the same way as heat pipes do. But since it’s not linear anymore, they can collect heat and vaporize the working fluid in several areas and it will naturally send those hot vapors on the coolest parts of the vapor chamber. It’s much more efficient and can even eliminate the need for fans on laptops with metal chassis.
Another cooling system that vapor chambers beat is liquid cooling systems; evaporative cooling that happens inside vapor chambers is just faster and more efficient at moving heat compared to liquid cooling systems which rely on convection and conduction to do the job. Although, we shouldn’t forget that vapor chambers have a limited scope of temperatures they can work with!
But to sum it up, one main benefit that vapor chambers have over heat pipes or any other cooling component is how thin and small they can be made. It allows laptops and tablets to be more compact and thinner without worrying about cooling, and it makes cooling possible on devices like smartphones that can’t be actively cooled before.
Applications of Vapor Chamber Cooling
The very first application of heat pipes is for cooling satellites in space and yes they do work in zero gravity, isn’t that cool?
Going back, an object in orbit like a satellite is prone to extreme temperatures; one side might be facing the sun making that side extremely hot and the other side facing deep space can get extremely cold, and as you might expect, electronic components won’t like that. To equilibrate the temperatures inside a satellite, it is lined with heat pipes to cool the hot side and warm up the cold side.
We already discussed the applications of heat pipes on HVAC systems and electronics at the beginning of this article. But another interesting application of heat pipes and vapor chambers is on batteries! Especially on Electric Vehicles.
But overall, vapor chambers can be used to cool everything as long as it can fit within that device, and considering that vapor chambers can get as thin as 3mm, it can be a pretty long list of future devices that can be cooled with vapor chambers.
Drawbacks of Vapor Chambers Over Other Cooling Components
While vapor chambers are an efficient and effective way to cool electronic devices, there are some drawbacks. Vapor chambers are difficult to manufacture and require a lot of time and money. The process of making these components involves many steps that can be very tedious and expensive, and it gets much harder as the vapor chamber gets smaller.
Other than the general complexity and cost, vapor chambers are also structurally weak. I know this is specifically made to cool components, not to be a structural member and provide stiffness within the electrical components. But you have to remember that as the name implies, there are hollow chambers inside these things, and since they’re also at a vacuum, one good squeeze is all it takes.
There is also fluid inside these chambers, remember? So if the already structurally weak chamber gets punctured or breached in some way or another, it not only takes a hit with cooling efficiency, but the fluid inside can also cause a short circuit if it leaks out.
But overall, I think the drawbacks are nearly negligible if you’re going to use vapor chambers on a device that isn’t meant to be serviceable by the user, for example, a smartphone, or maybe even laptops and desktops that Apple makes. It can still be used on PCs though, there are even hybrid coolers that integrate vapor chambers as a mean to transfer heat more efficiently and quickly to the heatsinks and fans.
Well, there you have it! Do you think vapor chambers are worth it? Are there any cooling methods that you prefer over vapor chambers? Your opinions are welcome here so make sure to leave them in the comments below! Thank you for reading!
Leave a Reply
You must be logged in to post a comment.