Mineral Oil Cooled PC

• Original System Launch (May 2007)
• Improving Cooling Performance (July 2007)
• 6 Month Update (Dec 2007)
• 1 Year Update (June 2008)
• 3 Year Update (July 2010)


• V2 DIY Kit Launch (Oct 2008)
• V2 2 Year Update (Jun 2010)


• V3 DIY Kit Launch (Jul 2010)
• V3 Phase Change Cooling Cooling (Aug 2010)


• V4 DIY Kit Launch (Oct 2011)
• MicroATX and Mini ITX DIY Kits Launched (Sept 2013)

Original System Launch

Eclipse System 6 Aquarium $60 from Premium Aquatics The Eclipse System 6 ended up being nearly perfect in size -- we couldn't have asked for better dimensions!

Lian-Li Motherboard Tray $25 from Performance-PCs Designed as a removable tray for Lian-Li cases, this allows us to cleanly mount all the computer hardware, then simply slide it into the aquarium.

5-6 Gallons Mineral Oil $120 from STE Oil You'd be amazed how difficult it is to find quantities of mineral oil locally. We learned that it is given as a laxative to horses, so you can talk to a local vet to get it, though you get some funny looks.

Using the primary components above, we hacked together our first system. The setup is quite simple -- we made a few cuts to the top brackets on the aquarium, and cut a sheet of acrylic panel to provide a flat base for the motherboard tray to rest on. We later found we needed a better solution for the power supply -- it is a bit clunky just sitting at the bottom of the tank. It made maintenance difficult because the motherboard tray could not be easily lifted from the tank without dragging the power supply along with it. We didn't intend to run the system with fans, but once we saw them spinning slowly in the oil, we just couldn't resist keeping them! With the oil, they made no noise at all. We started with the cheapest hardware possible, just in case the whole thing blew up! When the first test went perfectly, we moved up to modern hardware.

One of the best things about this setup is that the oil evenly distributes the heat. You don't have nearly as localized hot zones as you do in an air cooled computer. But how well does it dissipate the heat?

Idle Temperature

The mineral oil has considerable specific heat capacity, which means it can absorb lots of heat. Because of this, it takes the system quite a while to work up to its equilibrium temperature. Starting at an ambient 29C on the CPU, we found it took about an hour to hit a stable idle CPU temperature of 37C.

Load Temperature

The system under load was a different story. We put the system under full CPU and GPU load, and watched the temperatures climb. It took a really long time. After 12 hours, the system topped out with a CPU temperature of 88C. Yes, that is *really* hot. The system was rock solid and didn't crash when running stress tests for 48 hours at these temperatures, but we do not recommend running anything close to this hot, as the acrylic can easily crack at that temperature. We later added a radiator to solve this problem.

Another question we wanted to answer was how quickly the system cooled once we stopped the stress testing. It dropped back to an idle baseline in just about 8 hours.

Did Bubbles Help?

After we saw the high maximum temperatures, we started to think about what would happen if we pumped bubbles into the system. Theoretically, since the bubbles composed of cooler outside air, they should pick up the heat, rise and release it to the air above. Did it help? After about 2 hours, the temperature settled at a new maximum of 84C on the CPU under load. The bubbles did have an effect, but not as much as we were hoping for. Interestingly, the bubbles also hurt the video card temperature, causing it to rise by a few degrees! It seems the bubbles also served to agitate all the contents of the aquarium, bringing everything to a more consistent temperature throughout. For this reason, we do recommend bubbles.

We had a lot of fun building a system like this, and now that you know you only really need to spend about $150 on all the materials, we encourage you to give it a try if you've been thinking about it. Of course, we're not responsible if you blow up your computer! In the end, this is a novelty, of course. There is really no other reason to build a system like this...but it will certainly be a great attention getter when we display it prominently at our office! If you're in Seattle, feel free to stop by and check it out.

Improving Cooling Performance

The biggest issue with our initial V1 system was inadequate heat dissipation. Mineral oil has a terrific specific heat capacity, so it took a very long time to reach peak temperature -- about 12 hours. However, that temperature was too high, at 88on the CPU. On the one hand, we had absolutely no problems with stability with over a month of usage at those temperatures. The oil did a good job of making sure everything was a very consistent temperature. With a normal air cooled computer, you have a handful of hot spots. With the oil eliminating these hot spots, we had no problem running a rock solid system. On the other hand, 88C is way too hot for acrylic. What could be worse than the tank cracking and spilling the hot oil!? We wanted better temperatures. We've received dozens of different recommendations on how to best cool the oil, some extremely complicated. We elected to simply pump the oil directly through the radiator. We do a lot of liquid cooling here at Puget, so we have a lot of materials on hand.

The results were very good! Within 8 hours, the temperature dropped to a new maximum of 45C on the CPU. If we wanted to get even better cooling, we could hook up some fans to the radiator, but 45C is an excellent CPU temperature as it is, and we prefered the quiet operation with no fans.

Update After Six Months

The machine is still up and running with no problems! We made a few more alterations:

• We took the power supply out of its housing. This makes it much smaller, and less in the way. This is a great improvement to the look of the machine. This does remove the fan from the power supply, but it was already clear that the fans were not necessary. There is a real risk of shock if you don't handle it properly, but without the housing, the power supply would look much more at home in a system like this.


• We added blue crushed rocks to the bottom. It adds a finished look to the system, and gives it even more of an aquarium theme. We checked carefully to make sure the rocks were not conductive, since they come into direct contact with the power supply.

The fans are still running strong, just like they did on day one. Two times now, we have seen some oil on the countertop, and paniced thinking we had a leak, but each time ended up being a false alarm. It seems some days the bubbles tend to "foam" the top of the mineral oil, and this foam was spilling out of the aquarium. We just turned down the bubbles a bit, and everything was fine. It is curious that this only happens on certain days. Perhaps humidity plays a part?

Update After One Year

The machine is still running strong! We are having no problems with stability, and it has now been running for over a year, most of the time at 80C (still not recommended...the arylic could crack)! It is very easy to lower the temperature through a radiator, or just putting the system into standby at night, but we wanted to see if stability would be affected by higher temperature.

• The fans continue to run strong. We're amazed by the number of people that continue to be concerned that the fans will burn out. It is now very clear that the fans have absolutely no problem running in this environment.


• There is no sign of weakening of rubber seals or PCB. We have found that prolonged exposure to mineral oil does not eat away at any components. However, you will notice in the pictures that the voltage module for the LED light has fallen down. That module was stuck in place with nothing more than a sticker -- it took 9 months for it to come down! We're amazed it stayed up that long, but definitely recommend you do not rely on stickers or tape to fasten anything. Zip ties will be more solid and long lasting.


• The CCFL light has turned from blue to purple. We aren't sure whether that is due to the oil, because we've seen it happen with other CCFL lights in regular computers.


• The oil has gotten slightly murky. It isn't a very large change, but it is definitely there. This oil has been sitting, unfiltered, for a year, so it isn't really surprising! A quick pass through an oil filter (maybe even a coffee filter!) or a change of oil once a year is all that would be needed to counter this problem.

We have also gotten many requests for pictures of the top of the system without the plastic cover. Here they are!

Overall, the biggest downside we have found is that the oil wicks down the cabling and makes a mess. Its amusing at first to find oil seeping out of your mouse, but gets annoying very quickly! We recommend making extensive use of wireless (especially bluetooth) for a system like this. There's no reason why you can't run only a power cord and video cables to the box, and take care of everything else wirelessly. We completely solve this issue later with our V2 system under development. Every day, we're coming up with improvements we'd like to make to the machine.

Update After Three Years

Though the PC was still running strong, the hardware was getting older, and we wanted to upgrade to something faster! At our office, we upgraded to our V2 system! Still in fully working condition, this original system has been retired to storage, and we'll pull it out from time to time to see if there are any ill effect over long term oil submersion.

V2 DIY Kit Launch

While our original aquarium computer was still running strong, there were number of updates we wanted to make to the design. We decided to build a "Version Two" system, with these improvements. The biggest design improvement is that we have designed an acrylic motherboard tray, which is completely customized for this application, in this aquarium tank. Not only does this take the polish of the project to an entirely new level, but it makes assembly easier and the system much more secure. The other major design improvement came in the cooling system. We wanted to create a radiator system that was more compact, and that placed the pump submerged in the oil, for quieter operation. We built this system for demonstration at PAX 2008, and it was a complete success! It has allowed us to run an extremely high end system at under 50C with virtually no noise. It has also allowed an overclock of a QX9770 from a stock frequency of 3.2GHz, to an overclocked frequency of 4.6GHz!

The view of the top with the cover off shows how much the custom acrylic motherboard tray improves the project. We were able to design mounting holes for CCFL lights, which allows us to permanently zip tie them in place rather than have to rely on adhesives. The tubing to the radiator uses quick disconnect valves, so you can quickly add and remove the radiator depending on your cooling needs. We mounted four Antec Tri-Cool fans to the radiator, and ran them on the low setting, for very quiet operation. The loudest part of this system is the bubble bar!

The custom motherboard tray also allows us to install a power socket, and a control valve for the air hose. These connection points serve a distinct purpose! By not running any cables directly into the oil, we prevent wicking. The connection points break the suction, and has effectively stopped the wicking we saw with version one. A power cord extension is run down to the power supply at the bottom of the tank, and in this system, we directly soldered the cord to the power supply, to eliminate the bulky socket. In this system, the pump and hard drive (solid state) are both submerged. Using a special bracket, we are able to secure them both in the oil. We also used a larger heatsink, but performance was about the same.

How well does this setup cool? AMAZINGLY well! In this system, we put in the best hardware available at the time -- an Intel QX9770 overclocked to 4.6GHz, 8GB of DDR3-1600 memory, and a NVIDIA GTX280 video card. It ran at 50C under full load, and that was with our fans on the low setting! This graph shows the CPU temperatures we saw as we ran 3DMark Vantage, then let the system idle. You'll notice the temperature barely changes at all -- the radiator handles the heat with ease!

Two Years Later, Still Running Strong!

We continue to run our V2 system as a workstation for one of our employees, and it is still running strong with no problems. The oil has remained quite clear, there have been no leaks, and the cooling system is running as strong as on day one!

V3 DIY Kit Launch

As we continued to learn from our original Aquarium PC, and as we used our Aquarium PC V2 in our office, we kept a list of all the things we'd do differently or improve. The Aquarium PC V3 represents these improvements! The system is larger, allowing for full eATX motherboards. The biggest improvement is that it allows the power supply to be mounted on the motherboard tray, making it much easier to maintain the PC, as you don't have to worry about the power supply sitting on the bottom of the tank as you pull the motherboard tray out of the aquarium. It also has more than twice the cooling power! We built a test system with the most extreme hardware available, with impressive results.

Under full load with Prime 95 (16 threads) and FurMark (multi-GPU mode), our test system pulls a staggering 820W from the wall! That is a lot of heat to dissipate. We used Antec tri-cool fans on the radiator, and we tested the system with the fans on low speed (very quiet), and on high speed (no so quiet). Even with the fans on low, the system maxes out at just over 60C. When pulling 820W of power, that's a very impressive number! It took the system about an hour to reach maximum temperature.

At idle, you see the submersion cooling shine even more. Even though the extreme test system is still pulling 230W from the wall (which is high for a PC), the cooling system easily handles the load, reaching a CPU temperature of around 27C with fans on low speed. This is only a few degrees over ambient, and can be confirmed by placing hands on the tank: it is only mildly warm to the touch! Again, the system takes about an hour to reach its bottom temperature once we cut off the load.

Design Improvements

	Larger, Sturdy Frame: Mineral oil submersion is very effective at cooling extreme PCs, but extreme PCs take up a lot of space! The new V3 kit is larger, allowing for more room to work, and more room to fit high end components. Walls down the side of the motherboard tray allow for mounting of more components, and also add a great deal of rigidity to the tray. This is important because as you lift the tray out of the aquarium, you don't not want it to flex and loosen your components!
	Ease of maintenance: First, the V3 Kit mounts the power supply on the motherboard tray, which is a huge improvement over the lack of a power supply mount on the V2 Kit! It makes the entire PC into a single unit, so if you pull it out of the tank, you don't have to worry about cables or wires -- everything moves together. Second, with the larger tray, we are able to create a larger access port. Our goal was to make the port large enough for most people's hands to fit through. This makes it much easier to reach into the tank and make fast adjustments. Third, we have added lift handles to the top of the motherboard tray, making it much easier to lift up and out of the tank.
	Cable routing: Mounting the power supply on the motherboard tray means that you gain much more control over your cable routing. We provide holes throughout the tray (especially along the side walls, and across the bottom) to allow you to firmly zip-tie your cabling in place. It looks great!
	Fits full eATX Motherboards: You can fit up to an EATX sized motherboard onto the tray, allowing you to use extreme dual processor motherboards! If you use a mATX or ATX motherboard, you expose additional cable routing points along the motherboard tray, and allow for mounting of additional lighting.
	Fits multiple full size video cards: We make sure that the video card area is completely clear of obstructions. You have room to mount even the longest length video cards, and you can fit up to three video cards into the system with no modding required!
	Mounts extended length power supply: Anticipating high end configurations, we wanted to make sure that you have room to fit even the most extreme power supplies. We have kept the area below the power supply clear, allowing you to mount very high end, long length power supplies.
	Enormous cooling capacity: The V3 kit uses a larger radiator, with a 3x3 grid of 120mm fans. With 9 fans, you can run them all on low speeds, allowing for both quiet operation and extreme cooling!
	Dual pumps: We use 1/2 inch tubing and need dual pumps to provide the flow rate necessary to make good use of all the surface area provided with the larger radiator. This not only improves performance, but adds redundancy. It also gives the system enough power to pump the fluid through the radiator with no priming necessary, making the system much easier to set up.
	Hard drive mounts: The larger size of the tray gives us room to provide mounting points for both a 2.5 inch hard drive (such as a SSD) and a full size 3.5 inch hard drive. We provide spacers to lift the hard drives off the tray by a small amount, allowing airflow around the hard drives, keeping them cooler.

Phase Change Cooling Development

While we were very happy with the cooling performance of this unit, we actively researched methods to try to bring the oil to sub-zero temperatures! We tried a number of different extreme cooling techniquies, including dry ice, phase change cooling, aquarium chillers, and liquid cooling blocks with TEC coolers. Ultimately, the snag was always the same: The thermal conductivity of oil is not as good as that of water, so all products designed to cool water do not have the sheer surface area necessary to cool the oil. It is possible that you can build your own aquarium chiller, taking care to dedicate a large amount of extra copper coils to the oil side of the heat exchanger. However, we have spent a lot of time on this, and have to get back to our main jobs -- building high quality computer systems! We encourage those with experience in phase change cooler design to pick up this ball and run with it, and if anyone can achieve a sub-zero cooling technique, we'd love to talk about it and post it here. Our standard radiator setup does a great job of cooling, so we're happy leaving our project there...but sub-zero would be pretty amazing!

V4 DIY Kit Launch

We continue to make design improvements, rolled into our latest V4 release. We have now purchased our own laser cutting machine, which allows us to bring manufacturing in house. This will speed up future design improvments, and will improve the overall quality of the product. With V4, we move back to a single pump design, which is much simpler, and therefore more reliable and quite a bit less expensive! For more details and to purchase a V4 DIY kit, check out our ordering page with this information.

MicroATX and Mini ITX DIY Kits Launched

We've often heard how much someone wants to build an aquarium PC, but the cost of the EATX V4 kit is simply outside their budget. In order to provide more affordable aquarium kit options, we have developed two new DIY kits. The Micro ATX kit is a bit smaller than the current EATX V4 kit, but by utilizing multiple different cooling options has the exact same cooling potential as the EATX V4 kit. But if you do not need a massive 9x120mm radiator, you can greatly reduce the cost of the kit by purchasing more other, more modest, cooling options.

The Mini ITX kit, however, takes a completely different approach. Instead of offering multiple cooling options, we simply designed it to be as low cost as possible. While this does come with some drawbacks (for example, no PCI cards can be used), this is a great kit for those than want an aquarium PC at a very modest price.

With this launch, we are also completely changing how we sell our aquarium kits. It is now easier to purchase all the items you need including fans, grills, and accessories. Check out our new configure page and configure a kit yourself!

Micro ATX Gallery	Mini ITX Gallery