How vapor chamber cooling works

Graphic illustration of heat exchange process inside a vapor cooling chamber.

The name reflects vapor chamber cooling, a vapor-filled chamber for cooling. The vapor chamber is a flat pipe that contains a liquid that can evaporate and then condense easily without a mechanical condenser. The fluid absorbs heat from a source and changes into its vapor state. These vapors travel to the cooler parts of the chamber, where it condenses and gives off the absorbed heat. This is repeated until the heat is evenly distributed throughout the vapor chamber.

This vapor chamber is a thin pipe that is flattened to about a millimeter to ensure it doesn’t increase the thickness of the device. However, manufacturers may select different materials to ensure better heat radiation away from the chipset. Xiaomi can similarly assist you with smartphones.

The wide range of heat exchanges made from smartphone chipsets of which the Snapdragon 8 Gen 1 is a popular example has forced smartphone companies to use more advanced cooling methods. The vapor chamber is usually stacked with as many as six or seven layers of different materials, all of which combine to dissipate heat away from the processor.

Smartphone companies have taken a step further in developing their designs. For example, Xiaomi recently showcased its loop lithium-cool technology, which uses microvalves inside the cooling chamber to increase the surface area through which the hot vapors travel. The greater surface area allows the vapor to condense faster and the liquid to cool further.

Examples of phones with big cooling promises

For mobile gamers, smartphone manufacturers and designers discuss vapor chambers and their configurations in detail. The recently-launched ASUS ROG Phone 6 includes sheets of graphite, the same material used to make pencil leads. The vapor chamber is higher by 30% on the ROG Phone 6 than on the ROG Phone 5 to meet the demands of the better-performing chipset.

The OnePlus 10 Pro, for example, has a five-layer cooling system, and the Realme GT 2 Pro has nine layers, one of which is made of stainless steel.

Certain brands are known in terms of the total area of the cooling apparatus. For example, the Realme GT 2 Pro is claimed to have a cooling surface of around 36,000 square kilometers (mm2) roughly three times the surface area of the phone’s back. However, realme also claims that the vapor chamber alone has a total surface area of over 4,000 square millimeters.

In the case of multi-layer cooling systems, heat dissipation occurs in a three-dimensional space. The vapor chamber absorbs the heat from the chipset and transfers it to the cooler parts. During the same time, some heat is also radiated to other layers, and each layer further dissipates heat throughout its entire surface.

Some phones (such as ZTE’s Nubia RedMagic 7 Pro) use fans inside to eject the heat even more efficiently. Likewise, some other phones, such as the ROG Phone lineup, have external fans that assist in cooling down the rear surface of the phone. You may also purchase these fans as separate accessories and use them with any smartphone.

If these statements do not align with real-world performance, they will do nothing wrong.

Putting phones vapor cooling to the test

I decided to experiment myself with these three phones: the Samsung Galaxy S22 Ultra, the OnePlus 10 Pro, and the Realme GT 2 Pro. These phones are backed by the Qualcomm Snapdragon 8 Gen 1 chipset, which is renowned for its heritability, and these are popular handheld processors. Moreover, these phones also feature metal frames, which allow for greater heat dissipation outside the device.

I conducted three tests to strain the processor, resulting in significant heat generated. These tests include running PUBG: New State Mobile is a mobile game that is demanding, and two benchmarks are particularly significant on the CPU and GPU.

These tests are conducted without requiring a protective case, as they can impede heat from radiating into the atmosphere. In each case, the brightness of the phones was set to automatic, with the screen resolution set to QHD+, and the refresh rate was set to 120Hz. Lastly, all these tests were conducted at an approximate ambient temperature of 25 degrees Celsius (77 degrees Fahrenheit).

The results of these tests are the following:

On PUBG: New State Mobile, I played a battle royale match for the first time. I observed the temperatures of the CPU using the CPU Monitor app as well as the temperature on the highest external surface at several intervals from the start of each match.

These tests were performed at the game’s highest graphics settings, and the results based on the trial run are as follows:

  • Samsung Galaxy S22 Ultra
10 minutes 15 minutes 20 minutes 25 minutes CPU CPU
CPU temperature (C) 37 38 40 42
Surface temperature (C) 40 41 42 43
Difference (C) 3 3 2 1
  • OnePlus 10 Pro
10 minutes 15 minutes 20 minutes 25 minutes CPU CPU
CPU temperature (C) 42 45 45 45
Surface temperature (C) 38 39 39 40
Difference (C) 4 6 6 5
  • Realme GT 2 Pro
10 minutes 15 minutes 20 minutes 25 minutes CPU C
CPU temperature (C) 41 40 39 40
Surface temperature (C) 39 38 38 38
Difference (C) 2 2 1 2

The Galaxy S22 Ultra, the OnePlus 10 Pro, and the Realme GT 2 Pro’s inner and outer temperatures are around 2 degrees Celsius, 5 degrees Celsius, and 2 degrees Celsius. Interestingly, the OnePlus 10 Pro found that it provides the most effective insulation between the chipset and the outer surface. Nonetheless, the internal temperature on the Realme GT 2 Pro remains significantly lower, indicating that it has improved heat dissipation inside the body.

The Galaxy S22 Ultra has a different pattern wherein the internal temperature is lower than the outer temperature. In the same way, the internal temperatures are the lowest in the competition, indicating that it is the best in the lot to effectively dissipate heat during intense scenarios such as playing the game.

The average internal and external temperatures are arranged in the figures below:

The Galaxy S22 Ultra reveals the lowest average internal temperature, but the Realme GT 2 Pro comes ahead with the lowest average temperature on the outside surface.

GFXBench, a synthetic benchmark used to measure the performance of the CPU and the GPU by simulating graphics-intensive tasks, was used in our second experiment. I calculated the internal and external temperatures for each of the three phones, according to the values:

Samsung Galaxy S22 Ulta OnePlus 10 Pro Realme GT 2 Pro
Starting internal temperature (C) 32 26.2 28
Ending internal temperature (C) 46 50.5 44.4
Starting external temperature (C) 30.9 39 29
Ending external temperature (C) 42.7 56 56

The following diagrams show the temperature predictions.

The dotted line represents the internal temperatures of the chipset, while the flat line represents the external temperatures on the three devices. While using GFXBench, the Galaxy S22 Ultra demonstrates the most negligible temperature surge. Although the Realme GT 2 Pro is successful, the heat produced is still nowhere as good as the Galaxy S22 Ultra.

We performed the CPU Throttling Test app for the third and final test on the three smartphones, which again takes place to determine how much heat the phone heats and, in turn, reduces performance. At the end of the test, we completed the internal and external temperatures.

The Galaxy S22 Ultra has the least internal temperature, while the OnePlus 10 Pro has the lowest external temperature despite being the hottest inside.

Vapor chambers on phones aren’t going anywhere

Cooling techniques, which are the most crucial part, play a crucial role in keeping the phone’s internal temperature under control. This also ensures the smartphones” external temperatures are not too high, as long as it’s difficult to hold them. In some instances, the phone shuts automatically to cool down, which is also undesirable.

Our results show that all three phones are capable in front of tough environments, and each has its benefit. The Galaxy S22 Ultra is the coolest based on our testing, while the OnePlus 10 Pro maintains its ground despite running hotter internally. Despite its 9-layer cooling setup, the OnePlus 10 Pro works the hardest to keep internal temperatures from raising the temperature of the external body.

A vapor cooling is expected to be implemented more rapidly in future versions of our smartphones. One of the most significant of those is the iPhone 14 Pro, which is reportedly designed to feature a large vapor cooling chamber. In the future, we may expect vapor cooling to be more widespread. A cyberpunk future is incomplete without fluorescent liquids cooling all sorts of electronics and electrical systems.