Measuring The Cooling Effect Of Transformer Oil

Transformer oil has long served two purposes, cooling and insulating. The large, steel encased transformers we see connected to the electrical grid are filled with transformer oil which is circulated through radiator fins for dumping heat to the surrounding air. In the hacker world, we use transformer oil for cooling RF dummy loads and insulating high voltage components. [GreatScott] decided to do some tests of his own to see just how good it is for cooling circuits.

Thermal measurement resultsHe started with testing canola oil but found that it breaks down from contact with air and becomes rancid. So he purchased some transformer oil. First, testing its suitability for submerging circuits, he found that he couldn’t see any current above his meter’s 0.0 μA limit when applying 15 V no matter how close together he brought his contacts. At 1 cm he got around 2 μA with 230 VAC, likely from parasitic capacitance, for a resistance of 115 Mohm/cm.

Moving on to thermal testing, he purchased a 4.7 ohm, 100 watt, heatsink encased resistor and attached a temperature probe to it with Kapton tape. Submerging it in transformer oil and applying 25 watts through it continuously, he measured a temperature of 46.8°C after seven minutes. The same test with distilled water reached 35.3°C. Water’s heat capacity is 4187 J/kg∙K, not surprisingly much better than the transformer oil’s 2090 J/kg∙K which in turn is twice as good as air’s 1005 J/kg∙K.

He performed a few more experiments but we’ll leave those to his video below.

We’ve run across a number of tests running boards submerged in various oils before. For example, we’ve seen Raspberry Pi’s running in vegetable oil and mineral oil as well as an Arduino running in a non-conductive liquid coolant, all either overclocked or under heavy load.

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Water Cooling a 3D Printer

It may seem like a paradox, but one of the most important things you have to do to a 3D printer’s hot end is to keep it cool. That seems funny, because the idea is to heat up plastic, but you really only want to heat it up just before it extrudes. If you heat it up too early, you’ll get jams. That’s why nearly all hot ends have some sort of fan cooling. However, lately we have seen announcements and crowd-funding campaigns that make it look like water cooling will be more popular than ever this year. Don’t want to buy a new hot end? [Dui ni shuo de dui] will show you how to easily convert an E3D-style hot end to water cooling with a quick reversible hack.

That popular style of hot end has a heat sink with circular fins. The mod puts two O-rings on the fins and uses them to seal a piece of silicone tubing. The tubing has holes for fittings and then it is nothing to pump water through the fittings and around the heat sink. The whole thing cost about $14 (exclusive of the hot end) and you could probably get by for less if you wanted to.

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Water-Cooled LED Light

[Matt] wanted to drive a Yuji LED array. The LED requires 30 V and at 100 watts, it generates a lot of heat. He used a Corsair water cooling system made for a CPU cooler to carry away the heat. The parts list includes a microphone gooseneck, a boost converter, a buck converter (for the water cooler) and custom-made brackets (made from MDF). There’s also a lens and reflector that is made to go with the LED array.

This single LED probably doesn’t require water cooling. On the other hand, adding a fan would increase the bulk of the lighted part and the gooseneck along with the water cooling tubes looks pretty cool. This project is a good reminder that if you need to carry heat away from something with no fans, self-contained water cooling systems are fairly inexpensive now, thanks to the PC market.

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Georgia Tech Pumps Water Through Silicon for Chip Cooling

One of the things that stops electronic devices from going faster is heat. That’s why enthusiasts go as far as using liquid nitrogen to cool CPU chips to maximize their overclocking potential. Researchers at Georgia Tech have been working on cutting fluid channels directly into the back of commercial silicon die (an Altera FPGA, to be exact). The tiny channels measure about 100 micron and are resealed with another layer of silicon. Water is pumped into the channels to cool the device efficiently.

A comparable air-cooled device would operate at about 60 degrees Celsius. With the water cooling channels cut into the die and 20 degree water pumped at 147 ml/minute, the researchers kept the chip operating about less than 24 degrees Celsius.

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A Watercooled Headlamp, Because Why Not?

There are extremely high powered LEDs out there, and most of the ‘creative’ uses of these are extremely high-powered flashlights, complete with heatsinks, forced air cooling, and beefy power supplies. [Christian] wanted to play around with one of these LEDs, but he wanted something a little more unique. He chose a headlamp, a build that is made even more impressive by the fact it is watercooled.

The body of the headlamp was milled out of aluminum, with a space for the LED in the front and channels in the back for coolant. Also in this enclosure are two buttons, a temperature sensor, and a port for the hose that carries the tubes and wires.

This hose connects to a large battery pack that houses four large lithium phosphate batteries and a boost converter built around an Arduino. The pack also houses a pump and reservoir that is able to keep the LED cool even at 130W.

A PC rig that belongs on the wall of an art museum

When Overclock.net user [Show4Pro] decided to upgrade his “old dusty rig”, he eschewed the conventional PC form factor and instead built an incredibly sexy custom wall-mounted case.

The six sticks of RAM, quad HDD/SSDs, and dual Radeon HD7970s are enough to make all but the most hard core gamer blush, but that was only the beginning here.  Using a Dremel tool, Show4Pro cut the frame from a piece of hardboard and coated it with a mock-carbon fiber vinyl sheet.  This backdrop acts to both hide the (many) cables and provide structural support to the components.  Custom light guides cut from an acrylic sheet are back lit with LEDs and serve as a border for each of the components.

Laying all of the boards flat on the frame required the use of PCIe risers to move the video cards away from the mother board.  Long PCIe connectors are very susceptible to EMI though, and Show4Pro ran into a few stability problems that he eventually had to resolve with some high-end shielded risers.

Besides that one minor hiccough, the project went off without a hitch and it looks like his 100+ hours of work have really paid off.

Via Reddit.

Building the electronics for a Tesla coil… and watercooling them

A few years ago [Patrick] was offered the Tesla coil of a friend of a friend. This was an opportunity too good for him to pass up.

He then began the creation of an Off-Line Tesla Coil (OLTC), where no supply transformer is used. The incoming mains supply is rectified and directly fed into the tank capacitor.

[Patrick] therefore had to build a huge capacitor bank and more importantly his own primary coil, made with a 1.6mm (0.064″) copper sheet to handle the immense current involved. Air cooling the electronics was sufficient until he started using his three phase input supply. As more power involves more heat, a waterblock was designed to cool the main transistor.

Patrick’s write-up is very detailed and worth the read. Once you’re finished with it, we advise you to browse through his website, where a lot more cool projects are described.