There are some great instructables showing you how to build a Peltier cooler and I hope you will enjoy my version of it. Let's see how I recycled my old PC computer into a thermoelectric Peltier mini fridge with temperature control!
I had an old cpu that I was not using and wanted to give it a second life. I could not think of a better way than to build a beer cooler out of it. I used the ATX power supply and heatsinks from the computer as well as a Styrofoam shipping box I had. The fridge uses a thermoelectric Peltier device for cooling. Basically, you apply DC current to this small ceramic square to cool down one side whereas the other gets hot. The heatsinks are used to dissipate heat or cold on either side with the fans. The temperature control switch allows you to select the desired temperature. You can expect a 10-15 celcius temperature difference between the cooler and ambient temperature. In Fahrenheit, it went from 70 to 50 degrees. This cooler is obviously not as efficient as a classic compressor refrigerator but it’s a cool gadget that is cheap and easy to build! Check my ATX breakout board Instructables for more information about the lab bench power supply used in this project and how to build one. I hope you will find this information useful.
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Warning and disclaimer: ATX PSU can deliver enough current to cause serious injuries or death. I am not responsible for any accidents or damages.
Step 1: Everything You Need for This DIY Project
***Homemade Peltier Cooler Refrigerator (about 8$):
-Styrofoam shipping box (or any type of cooler you have on hand)
-Small and large heatsinks from an old PC computer or any heatsinks you may have
-Electrical wires (I'm using AWG14 wires and Dupont cables)
-Hot glue gun
***Homemade ATX lab bench power supply (check my instructables for more informations - about 8$)
-ATX power supply (I took mine out of an old cpu. They cost about 30$ US on eBay)
Step 2: Cut a Hole in the Lid of the Styrofoam Cooler
I’m using a Styrofoam cooler to build the Peltier mini-fridge (8 x 6.5 x 8 inches, can hold up to 8 cans).
You should use the smaller heatsink for the inner side of the cooler. Therefore, the hole should be the same size as this heatsink.
Step 3: Assemble the Peltier Module With the Heatsinks on Each Side
Before assembling the module, you should test the Peltier for a few seconds with a 1.5V battery to determine which side gets hot and place the larger heatsink on it.
I used a conductive thermal silicone pad to make the Peltier sandwich, but you can use thermal paste if you prefer. You can now place the smaller heatsink on the cold side and introduce it in the lid of the cooler.
Step 4: Fix the Computer Fans
I used hot glue to fix the fans. The smaller one needs to be placed over the small heatsink. I used a 24V fan for the inner side of the cooler even tough I'm using a 12V supply. This way, the fan speed is reduced as well as the heat it produced. Your fridge will therefore be a bit more efficient.
Step 5: Plug Everything
It seems a bit scary with all these wires, but it’s really easy to plug everything. You can use the largest wires (I'm using AWG14) to connect the ATX beakout board and the temperature control switch. The red wire connects the 12V rail of the ATX breakout board to the K1 connector of the temperature control switch and the black wire connects the grounds together. The +12V connector of the temperature switch should also be connected to the K1 port in order to power up the switch. I’m using a Dupont cable (in fact 2 cables because it was a bit loose with a single one) to connect these ports together. You can now connect the Peltier and computer fans to the K0 and Gnd connector of the temperature control switch. Check the wire diagram to make sure that you wired everything properly before turning on the mini fridge!
Step 6: Enjoy Your Mini Fridge!
You can now turn on the ATX breakout board to power your mini fridge. The temperature can be set on the control switch by pressing the set button and then adjusting the value by pressing the +/- keys.
You can access additional settings of the temperature control switch by pressing the set button for a few seconds and then adjusting the desired values. See the table for a full list of these options.
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