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Liquid Cooled Computer (Year 2000 High School Science Fair)

Middletown High School Science Project, designed and constructed in Spring 2000 by Cevyn Miles-Monaghan & Lance Forrest.


We embarked upon this project not knowing what to expect. We had built computers before, and overclocked them. But we were not experts on the laws of heat, nor did we have the necessary tools to do what we had in mind. We did not have a lot of cash laying around either, a total of about $500 was available for everything. This forced us to find cheap ways of doing everything, and we successfully did it! By using hand tools, we were able to produce a highly effective liquid cooled computer design proving that you don’t have to have thousands of dollars or any sophisticated machinery to do it. All photos were taken with a Sony Mavica floppy disk digital camera. The whole project took just a couple of months to complete.

Liquid Cooled Computer Project: Water Block, Part 1

These are most of the parts that we bought for building the liquid cooled computer. The various parts shown here include the motherboard, hard drive, pump, copper tubing, various fasteners and clamps, PVC plumbing cap, CPU, adapter card, plastic box and clear plastic tubing. Most of these parts were purchased at Home Depot, Radio Shack and Axion Technologies.

This is the motherboard that we chose for the project. This is a cheap ATX slot 1 motherboard designed for Celerons and Pentium IIs (Athlons were too expensive at this time!).

We got the above motherboard and this Celeron CPU with an adapter so that we could drop an Athlon into this setup when they are available for cheap in the future. This is a 400MHz Celeron in a slot 1 adapter card. We really wanted a Celeron 300a which is known to overclock extremely well but could not find one in stock.

This is a black plastic box purchased at Radio Shack. It will encase our processor and heat exchange assembly to protect other parts of the system should it spring a leak, and to serve as a mounting board for the heat exchange assembly. Remember, water and computers do not mix!

We marked the corner of this box to be cut out because we found that it would barely not fit with the ATX power connector being so close to the CPU socket on the motherboard. This was an unexpected problem but did not hinder our progress for long…

It was then time to cut the corner of the box out using a hacksaw and sanding drum on a Dremel tool.

The slot for the CPU card’s connector to go through was then marked and cut using a Dremel cutoff disc.

The CPU card was then installed into the black plastic box and installed to make sure that enough connector was showing on the other side to fit properly on the motherboard.

To make the water box which would allow the antifreeze to flow over the CPU and take the heat away, we hack-sawed the grip part off of a 4″ PVC plumbing cap that we got at Home Depot. This is the same type of cap that you see on the end of the pipes in your basement.

The heat sink we decided to use to take the heat from the CPU and put it in the antifreeze was an old 486 heat sink. We modified it to fit into the PVC cap snugly. Yet another cost cutting move…

We then wanted more surface area for increased heat transfer. This was accomplished by hack sawing additional slots into the fins of the heat sink, turning them into pins.

This is a small aluminum plate which will be fastened to the back of the heat sink above to allow it to be installed into the PVC cap properly and to be leak proof.

Here is an unused PVC pipe cap (we bought two just in case we messed the other one up!), the finished heat sink, and the sawed and sanded end of the other pipe cap.

The heat sink was then installed onto the metal plate using thermal epoxy. We did not have access to a welding machine to fuse them together which would have provided better heat transfer.

Another view of the heat sink installed on the metal plate.

Holes were then drilled into the side of the PVC cap to allow the pipe fittings to be connected. We used L shaped pipe fittings which we picked up at Home Depot.

We then clamped the metal plate to the PVC cap so that it could be smoothed for a better appearance.

Here is a photo of one of the many epoxy mixing sessions…As you may or may not know, epoxy is a type of glue which comes in two tubes and is mixed together to harden.

Simply screwing the L shaped fittings into the PVC box would have been too leak prone, so we sanded off the threads and used some epoxy on them too.

The L shaped fittings were then carefully installed into the PVC cap, and more epoxy was applied around them to make sure that absolutely no antifreeze could seep out. Antifreeze and rubbing alcohol (used for testing) can find leaks better than water can.

The L shaped fittings and PVC box after they are finished drying. They will never be separated from that PVC box again.

The heat sink on the metal plate was then installed using epoxy as well.

It was then test time. We took a windshield washer pump and put water through the heat exchange device to make sure there were no leaks. Rubbing alcohol was also used at one point to further check for leaking. No leaks were ever found in the water block.

Liquid Cooled Computer Project: Radiator, Part 2

Design of the radiator was the next priority. This device has to be constructed so carefully that extensive time was spent at the drafting board. Every little detail was planned out since there was no room for mistakes. We had only one heat plate (from an old carpet cleaner!), and the other parts were expensive.

More designing…

The radiator is responsible for cooling the antifreeze down. This was accomplished by putting the antifreeze through a copper coil which was so much fun to construct (sarcasm intended). We kept having creases in the tubing which meant we needed another way to make the coil…

Heat was our best friend. A propane torch provided the necessary temperatures to make the tubing easy to bend…well, sort of. It was still difficult but it did not kink as much. We were told after we finished the coil that we should have put sand in the tube to prevent kinking…go figure…

The finished coil…it took way too many hours to produce this coil. We could have bought a pre-made one, but finding one that was cheap and compatible with our design was impossible.

More testing. We placed the water box under HOT water and the coil warmed up rather quickly. The heat transfer device was functioning as planned, and no leaks have occurred.

It was now time to fasten the coil to the aluminum heat plate to provide a flat uniform surface for the peltiers. This was done again with thermal epoxy. If we were to weld all the connections made with thermal epoxy, the system would be much more effective. As we found out later though, the system was definitely effective enough for its purpose.

This system had to power a windshield washer pump, 3 peltiers and then the regular computer components. The power supply in the case was capable of only 300 watts. We were going over the maximum amperage on the 12 volt line of the power supply. The windshield wash pump also generated electrical noise which computers do not like. A second 250 watt power supply was taken apart and installed on top of the first one, and wired in to turn on simultaneously via a relay seen at the top. This second power supply ran the peltiers and the pump.

One of the more expensive parts of the project was the heat sinks for the radiator. These are excellent quality aluminum heat sinks which were to be the main method of getting the heat from the antifreeze into the surrounding air. We bought these directly from Alpha in Japan.

The finished coil and heat plate assembly after curing.

The heat sinks were then drilled and tapped as planned in the design stage above. The peltiers placement had been carefully calculated for the most efficient heat transfer. Peltiers are electronic devices which are literally heat pumps, making one side really cold and the other hot.

The radiator is tested after being constructed, minus the fan. We checked for proper heat transfer. Sure enough, the coil got cold quickly, and the heat sinks began to warm up. These heat sinks are so oversized that a fan may have been unnecessary!

The radiator was mounted to the back of the full tower case, and wired into the second power supply.

A large AC fan from Radio Shack was then installed onto the heat sinks. This fan is made of solid aluminum and is quiet.

Liquid Cooled Computer Project: Insulation and Testing, Part 3

The system was tested again with the fan wired in with the relay. Upon powering on, the radiator worked perfectly, The heat sinks barely got warm due to the large fan, and the coil got extremely cold and began to form a frost!

Returning to the CPU in the black box. Special heat resistant foam was cut to insulate the CPU from possible condensation.

A trusty metal coat hanger was then used to hold the water block to the CPU.

Another view of the CPU/water block assembly.

The plumbing was then completed.

Liquid Cooled Computer Project: The Coolant, Part 4

Low tox antifreeze was partially diluted with water to get the best of both worlds.

The system was then set up and without any of the other computer components, the antifreeze flowed for the first time. We let this run for quite a while to be sure that absolutely no leakage or condensation occurred in the wrong places.

The rest of the computer was then constructed, and powered on for the first time. No overclocking has occurred yet. The system is allowed to run for a while, and then the windshield washer pump starts to overheat! We attempted to install a heat sink and broke the pump in the process. A new fish pump was used in place of the wash pump which was much quieter. Apparently windshield wash pumps do not like to run continuously!

Liquid Cooled Computer Project: Overclocked and Burn-in, Part 5

The finished liquid cooled computer, overclocked as high as the cheap motherboard would allow which was only 533MHz 🙁 We designed the entire system to be flexible, so a slot or even socket Athlon can be used in a future upgrade.

Liquid Cooled Computer Project: The Aftermath

The liquid cooled computer won 1st place in the 2000 Middletown High School science fair, 1st place in the County science fair here in Frederick County Maryland, the Herbert Hoover Young Engineer Award, and the US Army Award. We presented this project by running fully 3D rendered animations of the construction process on the LCC itself, complete with a slide show of the photos seen on this page. A couple of months after the show, the second power supply failed. The cause is not known as less than 200 of the 250 watts were being used, and amperage was not above the specs. The computer itself has been disassembled, however the radiator and other parts still exist (2013).