Check this guide to find out what is a Peltier and to learn how to make a thermoelectric Peltier cooler DIY. These Peltier modules are really cool and easy to use!
I got the idea while looking for a cheap DIY thermoelectric refrigerator. Instead of using a classical compressor, these fridges use Peltier modules for the cooling. The main advantage of these devices is that there are no moving parts, no chlorofluorocarbons (CFC), they are controlled by changing the applied current, they have a longer life and are easy to replace if they ever break.
For this project, I used my ATX power supply with an ATX breakout board to create a homemade Peltier mini fridge or Peltier cooler box with a digital thermostat (W1209).
Check these Peltier TEC12706 modules on Amazon
Table of Contents
What is a Peltier?
Peltier modules are composed of a ceramic square containing two different types of semiconductors. The Peltier module acts as a heat pump when an electric current is applied to the module. One side of the Peltier is cooled while the other gets hot. There are two main types of modules taking advantage of the Peltier effect; the thermoelectric cooler (TEC) and the thermoelectric generator (TEG).
The TEG can stand higher temperatures and tends to be more efficient with greater temperature difference between the hot and cold side. These modules are mostly used to generate an electric current by heating one side while maintaining the other side cold. They are commercially used to build heat powered wood stove fans. For more information about TEGs, check my other post about thermoelectric generators. On the other hand, the Peltier module that I will be using for this project is a thermoelectric cooler (TEC). There are different types of TEC and I chose to use the TEC1 12706.
For your information, the TE refers to thermoelectric. The C stands for normal size compared to the small size (S). The number 1 represent the number of stage, which is usually one. The following numbers are used to define the number of couples and the current rating. The number 127 means that there are 127 couples of semiconductors. The higher this number is, the more conductive and efficient this module will be. The last number 06 refers to the current capacity of this Peltier module. In this case, the current rating of the TEC1-12706 is thus 6 amps. For more information on these Peltier devices, feel free to read more on Wikipedia.
Are thermoelectric coolers efficient?
This efficiency of the module depends on the temperature difference between the hot and cold side of the Peltier unit. These TEC modules are more efficient when the temperature difference between both sides are closer to each other. It is thus important to efficiently dissipate the heat and cold produced on each side.
How to make a Peltier cooler or mini-fridge using a thermoelectric module?
For this project, I am using the heatsinks I took from my old PC computer, but you can use any type of heatsinks you can find. To be more energy efficient, the heatsinks and Peltier module should be assembled using thermal paste or thermal conductive silicone pads. This way, the heat and cold will dissipate freely to the heatsinks and increase the efficiency of the Peltier cooler box.
I also use computer fans to dissipate the energy on both heatsinks. 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 though 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.
Make sure to test the Peltier module before connecting everything. You can use a 1.5V battery to see which side is the hot and cold side. You should connect the large heatsink and fan to the hot side and use a smaller heatsink and a smaller fan for the cold side. To build the Peltier mini-fridge, I used an old Styrofoam shipping box I had on hand. Again, the more insulation, the more efficient your homemade fridge will be. I chose this because it was easy to cut the lid and place the thermoelectric Peltier module in it.
AliExpress.com Product – Thermoelectric peltier module TEC1-12706 for DIY cooler refrigerator
How to use a W1209 digital thermostat to control the temperature of your DIY Peltier fridge
To control the temperature of my homemade Peltier fridge, I am using a W1209 digital thermostat. This temperature control switch is cheap and easy to use. You can set the desired temperature with a precision of 0.1 degree. A sensor will control the alimentation by turning the Peltier module on and off, depending on the settings.
Check the wire diagram at the end of this post to see how to connect everything to the Peltier device and the power supply. The TEC-12706 Peltier module can in theory use up to 6 amps, so it needs a good power supply. I used an old ATX power supply from my computer and converted it to a benchtop power supply using an ATX breakout board adapter.
DIY Peltier cooler efficiency
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 though 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. You can expect a 10-15 Celsius temperature difference between the cooler and ambient temperature. In Fahrenheit, it went from 70 to 50 degrees.
General conclusions about this DIY Peltier cooler
This cooler is obviously not as efficient as a classic compressor refrigerator but it’s a cool electronic gadget that is cheap and easy to build! Check my ATX breakout board Instructables or my youtube video for more information about the lab bench power supply used in this project and how to do the conversion of your ATX computer power supply. I hope you will find this information useful.
Material required for this DIY Peltier cooler project
Homemade Peltier Refrigerator :
-Peltier module TEC1 12706 (eBay) (AliExpress) (Amazon)
-Temperature control switch W1209 digital thermostat (eBay) (AliExpress) (Amazon)
-Thermal conductive silicone pad (eBay) (AliExpress)
-8cm Computer fan (eBay) (AliExpress)
-4cm Computer fan 24V (eBay) (AliExpress)
-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
ATX power supply conversion to lab bench :
-ATX Breakout Board (eBay) (AliExpress)
-ATX Power Supply (eBay)
Please see my Instructables page to learn more about this DIY Peltier fridge. Check also my previous post to see how to use a DT830B digital multimeter to measure voltage and amperage.
Warning and disclaimer
ATX PSU can deliver enough current to cause serious injuries or death. I am not responsible for any accidents or damages. Feel free to use the affiliated links presented on this page. The prices are the same, it is anonymous, and this way you can support the making of these videos.
I am building a smaller version. By cooler box is a pepper tin. I wired the fan and the cooler in parallel, controlled by a thermostat. What I found is that when the cooler shuts off, the heat from the hot side migrates to the cold side. At my scale, this is a big deal. The only solutions I know are: 1) put the fan on an off delay timer or 2) run it all of the time. Did you detect this problem?
Yes, I also noticed that. The solutions that you propose would be good. In fact, I opted for the second one and chose to run the outside fan all the time. Another option would be to use an additional W1209 thermostat to control the fan separately. This way, you can put the probe on the hot heatsink and set the thermostat to stop the fan once the heatsink cooled down to the desired temperature. Hope it helps!