RTX 4090 liquid cooled with 12,000 BTU air conditioner, RTX 5090 up next — GPU runs at 20C

PC cooled by 12,000 BTU air conditioner
(Image credit: 'Electrolytic sodium carbonate' on Bilibili)

A Chinese techtuber has designed a liquid-cooled PC system that hooks up to a household air conditioner unit instead of a PC-mounted radiator. The video creator, oddly named 'Electrolytic sodium carbonate' (ESC), showcases a rather normal-looking PC tower - but next to it, there is a 12,000 BTU air conditioning unit to supercharge cooling. The result is that the GPU runs at just 20 degrees Celsius under stress testing.

This project is ready to be the "perfect companion" (machine translation) for an upcoming Core i9-14900K with Nvidia GeForce RTX 5090 system, says ESC. However, as they are still waiting for a water block release for their graphics card these first tests have been completed using a Core i9-13900K PC system fitted with an RTX 4090.

This isn't ESC's first work in integrating powerful household air conditioning units with personal computer systems. The video host shows an established 'whole house' liquid cooling system that appears to have five loops available for PCs. We have pictures of the inside and outside parts of this cooling setup in the gallery.

Next up, the ESC video host talks about the increased TDP of the RTX 5090, which moves the power needle a not insignificant amount beyond the expected load of an RTX 4090. We are then introduced to the Xiaomi KFR-35GW air conditioner, which gets a nice bit of Nvidia – AMD – Intel branding, though we are not aware of any AMD components in the test system. This AC unit offers a quoted 12,000 BTU cooling power and typically consumes about 1.2kW. It measures 765 x 268 x 550mm, so is quite a lot bigger than the PC tower it is cooling, and a lot bigger than a 360mm PC cooling radiator.

We are then guided through the modification of the Xiaomi KFR-35GW. Some welding and pipe management later, and we see the liquid cooler reservoir ready inside the AC unit.

How well does this AC unit cool the test PC? After 40 minutes of "roasting" this PC by stress testing it with popular tools such as FurMark and the AIDA System Stability Test the system CPU cores are said to be only a couple of degrees hotter than when the test started.

ESC then took the AC unit outdoors, where it would normally be installed, and noted that the GPU temperature was just 2 degrees Celsius, with a 12 degrees Celsius hotspot. Running stress tests again saw these GPU temperatures rise to 20 and 36 degrees Celsius, respectively. Sadly, the video doesn't include charts for inside and outdoors, CPU and GPU, idle and load – those would have been very interesting.

During the video the host says that they are happy with the capability of the air conditioner-cooled PC as demonstrated, and believe it is ready for both the 14900K and RTX 5090 components, which are waiting in the wings, and any upcoming RTX 6090.

Mark Tyson
News Editor

Mark Tyson is a news editor at Tom's Hardware. He enjoys covering the full breadth of PC tech; from business and semiconductor design to products approaching the edge of reason.

  • Gururu
    I'm still waiting for someone to build a pc in a mini refrigerator.
    Reply
  • JayGau
    Gururu said:
    I'm still waiting for someone to build a pc in a mini refrigerator.
    That cannot work because the refrigerator is a very bad environment for electronics (humidity, condensation). What this guy did is good because the PC is still in the room in optimal environmental conditions and only the liquid coolant goes to the AC unit. It's how modern data center cooling work by the way, he didn't invent anything.
    Reply
  • Notton
    Gururu said:
    I'm still waiting for someone to build a pc in a mini refrigerator.
    A fridge works on the same principles as AC, except it's significantly less powerful.
    We're talking like maybe 60W peak to run the compressor on a fridge, and it isn't designed to run 24/7.

    Where as an AC is at least 600W and designed for 24/7.
    Reply
  • passivecool
    My Chinese is not so existent, but looking at the video, i'm thinking that's satire.
    BELIEVE it or NOT: people in other cultures also have a sense of humor.
    Reply
  • ezst036
    Its not like something a little bit like this hasn't been done before.

    https://cdn.mos.cms.futurecdn.net/eMPhYW2AxBn9qj8sgv6EsT-970-80.jpg
    At Computex, Intel Demos A 28-Core Processor Clocked At 5GHz (Updated)
    Reply
  • edzieba
    passivecool said:
    My Chinese is not so existent, but looking at the video, i'm thinking that's satire.
    BELIEVE it or NOT: people in other cultures also have a sense of humor.
    Why would it be satire? Sub-ambient cooling with evaporative loops is as old as custom PC watercooling (back when DIY was the only option). It was a 50/50 mix between people repurposing fridge/freezer compressors and using AC unit compressors.
    However, this particular build is not even a subambient chiller, but harkens back to the DIY watercooling staple of repurposing existing radiators. The radiator loop of the AC unit has been replumbed to cool a water loop directly, with no refrigerant or phase-change involved.
    Reply
  • USAFRet
    Gururu said:
    I'm still waiting for someone to build a pc in a mini refrigerator.
    That's been done many times.
    It does not work well. The fridge dies very soon.
    Reply
  • HexadecimalAsphyxia
    There is no compressor where it should be. It's using the condenser coil as a radiator. There is no refrigerant involved at all. Looks stupid. Just a big ugly radiator. This does NOT use Air Conditioning. Stupid Clickbait. WTF!
    Reply
  • Dementoss
    JayGau said:
    That cannot work because the refrigerator is a very bad environment for electronics (humidity, condensation). What this guy did is good because the PC is still in the room in optimal environmental conditions and only the liquid coolant goes to the AC unit. It's how modern data center cooling work by the way, he didn't invent anything.
    If the fridge interior has fan assisted cooling, as many modern fridges do, most of the moisture in the air is deposited on the heat exchanger and exits through a drain. So, if the door is kept closed, humidity will be kept low. As stated above though, the fridge won't last long as they are not designed for long periods of continuous operation.
    Reply
  • Charogne
    HexadecimalAsphyxia said:
    There is no compressor where it should be. It's using the condenser coil as a radiator. There is no refrigerant involved at all. Looks stupid. Just a big ugly radiator. This does NOT use Air Conditioning. Stupid Clickbait.yes, that what I was thinking, since coolant is usually a pressurized gaz, it couldnt have worked with those rubber fitting. So in the end, its just a big radiator with a big fan. Now do the same with with proper flare fitting and a working compressor, I am prety sure they could achieved well below zero levels
    Reply