We have arrived once more at the time of year when penniless (or bored) hackers try to figure out how to keep the place cool without buying an air conditioner. [Paul Stacey] sent us his solution of pairing up a CPU cooler kit with a beer fridge. The CPU heat sink is cut out of a liquid cooling kit and discarded. In its place a loop of plastic tubing enters the freezer of the beer fridge where it exchanges salt water from a reservoir. The cold liquid circulates through the radiator of the fan kit and gives up it’s cool goodness through the fan unit seen above. This method puts a cold-air fan right in front of you with a digital temp and fan speed readout on the LCD.

Our biggest concern here is that this might heat up the beer in the fridge. Still, it’s more automatic than using a homebrew swamp cooler. Then again, we’ve always had a soft spot in our hearts for our favorite gravity fed cooling method. Anyway, check out [Paul's] build methods after the break where he makes it look quick and easy.

We’ve already covered a pipe bomb mini-fridge this week, but inventor [Tom Chalko] provides us with today’s fridge hack. He noticed that chest-style (laying down, see above) freezers were more energy efficient when compared to normal stand up refrigerators at the same size, despite the colder temperatures involved. This is largely due to the fact that these chest-style freezers keep cold air in like water in a bowl, even if the lid is open. He has written a very thorough report on his findings (pdf), as well as a detailed walk through of the manageable task of converting a chest-style freezer into a chest-style fridge. In the end, his fridge only used 103 Wh of electricity on the first day to reach and maintain between 4° and 7° C (39° to 45° F), and he noted that 30% of that was just getting it up to temperature. After that, the fridge only turned on for roughly 90 seconds an hour, making it a very quiet fridge as well.

What looks like a potential WMD, requires a huge power supply, and has several fans and wires dangling off the sides? Why a mini fridge of course! Your cubical buddy at work may have a Perfect Coffee Mug, or a USB powered fridge but it wont be as large of a caliber as [CaptPikel's]. Little information about it is out thus far, but an Instructable is promised. We do however know that it uses 3 peltier coolers (assumed to be 60watt each) and can cool down to 46F while being underpowered! If only it held just a few more cans.

Reader [Will R] sent in a thermostat mod for his brew fridge. His friends had found a perfectly fine bar refrigerator and wanted to repurpose it for brewing beer. A previous batch of microbrew had been mangled by the Australian heat so they wanted something that could maintain the perfect temperature. The fridge’s built-in thermostat wouldn’t rise above 5 degrees so they had to build their own. [Will] used a 10K NTC thermistor to measure the temperature. It’s connected to an ATtiny25 microcontroller that does the comparison and determines whether to turn on the compressor. He referenced SparkFun’s relay tutorial for the switching side. Although he didn’t etch a board for this project, the design file is included along with all the code on the project site.

[via Dirk]