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| We desarmaremos a cooler for the curious |
We will start with this post, in which I disarmed a cooler of those that are plugged in the car (or home if you adapt it a minimum 5 amp transformer and 12V), to discover another fascinating use of semiconductors (thermoelectric effect) and electricity: the Peltier cells .
Long ago that he was looking at how to adapt a cooler and make the longest cold on long trips by adding a couple of Peltier cells (about €5 each) and a pair of computer heatsinks (cold side may take a smaller heatsink), but seen refrigerators prices (€ 44 which I purchased in the Eroski)not me I have much complicated, time is scarce (if I can I will ride mine later, but we'll see; there are other priorities).
Shortly after buy cheap refrigerator, and work pretty well plugged into additional lighter to the side socket boot (not cannot ask much the fridge for that price), I perceived that the heatsinks moved slightly; ( something it had loosened, so I disassembled it to secure better and step show you how it works;).
The Peltier cells are very useful if you have imagination; You can from refrigerate whatever you want (beverages, picnic boxes), to build some embellishment animated by a candle warming up the side, like a curious helicopter taking advantage that it also works on the contrary; If we cause differences in temperature (heating the hot side and chilling cold), it will produce a small current that we can produce with small and efficient engines (such as the vibrator mobile) a curious effect.
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| Curious helicopter powered by a sail and peltier cell |
Characteristics of the Peltier cells:
- They are inefficient cooling; consume much by frigoria.
- Able to generate electricity if one side is kept cold and the other warm.
- Does not vibrate or make noises when running (except the fans you need).
- Long-lasting; their semiconductors, working in a safe range, last many years.
- They occupy little space; ideal for cooling small appliances.
- They usually work between 5V and 15V DC; to more higher voltage power and consumption, but less efficient and shorter duration; resistance between 1.3 and 5Ω, depending on the cell.
Disarming the fridge
This has a few screws at the top; four small side and other hidden 10 under the rubber sealant rubber which we will carefully remove. The lid of the cooler part protects and directs the air from the fan to the heatsink on the cold side, which is fixed with plastic tabs.
Release the screws holding the heatsink to the Peltier cell:
We can lift, and at the bottom see heat sink; cell medium peltier set with white heat conductive paste, then a billet aluminum to overcome styrofoam insulation to the other side, where it is fixed the refrigerator of the part that is cooled, smaller.
The operation could not be easier; does not carry any power control; It is just a switch that feeds directly the two small fan motors and cell peltier, in addition to a small diode with a resistance to lower the voltage.
To be low power, there is little danger of that frosting, and after several hours of usage are kept as a 5 or 10 ° C difference less than abroad.
It would have to see how anything is if we put a pack of two stacked cells, (cold hot other side) thereby increasing the effect and getting still more temperature difference.
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| Detail of the conductive paste to improve contact |
To tie better heatsinks, I used the common silicone on the side of the styrofoam, enduring very low and high temperatures (- 60 ° to + 200 ° C, I speak from memory).
Now we can only go in reverse and mount it as it was, with care that the screws of the coolers is well secured, because if the cell did not make an adequate contact with sinks, it would quickly spoil and would very little cool.
Happy chapucillas and up to the next!
