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DIY Thermoelectric Generators: The Working Principle and How to Make One

Side Section of Thermoelectric Generator

Side Section of Thermoelectric Generator

Source: Wikimedia Commons

These days, a lot of people around the world have embraced green energy harvesting. Why? Simple! It offers electricity from wasted or different energy sources in an environment. Interestingly the system does all this without batteries or grid connection. Some of its energy and heat sources include thermal, solar, and radio frequencies. That said, thermoelectric energy harvesting technology is a source of energy—which falls under the green category. And it uses the Seebeck effect to change temperature gradient to electric power. So, are you keen on learning how to build a robust and reliable energy production converter? That is, One that produces electricity where the heat dissipates? Then, it would help if you considered making DIY thermoelectric generators.

In this article, we’ll’ teach you about the TEG, detailed steps on how to make one, and more.

Let’s begin! 

What Is TEG?

Thermoelectric Generator Diagram

Thermoelectric Generator Diagram

Source: Wikimedia Commons

The TEG or Peltier generator is a solid-state semiconductor device. Indeed, it changes the heat difference between the device’s layer to electricity (or a valuable DC power source).

Furthermore, it’s’ crucial not to confuse the thermoelectric cooler with the TEG. After all, they both have the same components. In truth, the thermoelectric cooler produces an electrical current when you apply voltage to the device. And it eventually becomes a thermoelectric device.

So, the electricity from heat stimulates the Peltier effect. Hence, the product moves heat from the cold to the hot side. But the thermoelectric generators help to remove or add warmth, especially for solid-state devices. Also, it comes with two different semiconductor materials that you can use for the Seebeck effect.

What is a Seebeck effect? It helps the TEG to start producing electrical energy when you subject it to a temperature difference across its flip sides. And this happens when the TEG’s’ configured internal structure uses some doped p and n semiconductors.

We’ll’ talk more about it later in this article.

How Do Thermoelectric Generators Work?

Before we jump into how thermoelectric generators work, it’s’ vital to understand their construction. 

Construction of the TEG

The TEG usually has two special semiconductors P-type and N-type, and each of the semiconductors has different electron power densities. That said, you can start by placing your alternating semiconductor pillars (p and n-type) thermally.

And the pillars should align. That is, the posts should be electrically in series. With this, you can use a thermally conducting plate on each side to join both pillars.

The tip here is to opt for a ceramic conducting plate—if you don’t’ want to add another insulator. So, when you apply a voltage to the semiconductors” free ends, the current will flow across the bimetallic junction.

Consequently, you’ll notice a thermal energy difference, which isn’t an occasional exception. In addition, the portion of the setup with the cooling plate takes up the heat (hot exhaust flue), and then it moves it to the other side of the device. 

Working Principle of Thermoelectric Generators

The thermoelectric generators work by using the Seebeck effect. And this effect happens when the semiconductors experience charge carriers moving within. But the charge carrier that you have will depend on the type of semiconductor you use.

For instance, charge carriers are holes in doped p-type semiconductors and electrons in the n-type. That said, from the semiconductor’s hot side, the charge carriers tend to diffuse. As a result, one end of the device will have a buildup of all forms of energy charges.

A Radiostope Thermoelectric Generator

A Radiostope Thermoelectric Generator

Source: Wikimedia Commons

Therefore, the buildup will generate a voltage potential that’s directly proportional to the difference in temperature across the semiconductor

What Is The Seebeck Effect

The Seebeck effect happens when an electrically conducting material develops an electromotive force between two points due to a temperature range difference. So, you can call the emf thermoelectric or Seebeck emf.

Also, the Seebeck coefficient refers to the ratio between the temperature range difference and emf. Then, the thermocouple helps you measure the potential difference across the ends (hot and cold) between two distinct module design materials.

Further, the potential difference is proportional to the difference in temperature (across the cold and hot ends). But, the downside of this effect is that it requires extreme temperature differences.

And this is the hard part of the system because excess heat on one side of the device will heat the other side. Hence, it may damage the TEG and produce zero electricity.

So, to maintain optimal response, only one side of your TEG should be hot, and the counter side should be relaxed. 

DIY Thermoelectric Generator

DIY Thermoelectric Generator

DIY Thermoelectric Generator

Source: Phys.org

Here is the list of things you need to build your DIY thermoelectric generator:

  • Candles (10)
  • Aluminum tray (1)
  • TEC (8)
  • Insulation tape (1)
  • Solder wire (1)
  • Aluminum plate (1)
  • X-acto knife (1)
  • Loctite (1)
  • Voltage regulator (1)
  • Soldering iron (1)
  • Thermoelectric paste (1)

Steps

Step 1- Fix and Solder the Thermoelectric Coolers

Start by using a ruler to confirm the dimension of your TEC(about 40 x 40 mm). Then, use your 8 TEC. But if you want more current and voltage, you can use 10. So, with the 8 TEC, the base of your aluminum tray should be 160 x 80 mm.

While you’re at it, ensure that your base is flat. That way, it’s’ easy to glue your TEC, allowing you to get the temperature gradient. Next, you can insulate the area where you’ll’ install the TEC  with the insulation tape.

Afterward, put some thermal paste on the blank side. While you’re at it, paste the TEC with the letters facing up. With this, you’ll’ see the wires form pairs (red and black). Apart from the TEC number 4 black wire and number 8 red wire, solder the other cables.

In other words, TEC 8 and 4 should remain loose. Then, you can complete the loop by soldering TEC 5 (black wire) to TEC 1 (red wire).

When you complete the process here, put some more insulation tapes on the soldering points. That way, the soldering issues won’t’ have contact with other surfaces. 

Step 2-  Create Your Stand

In this step, you need to consider the height of your aluminum tray, which is 50mm. With that in mind, add a TEC thickness of about 5mm. Then, the distance between the TEC and candle flames can be 15mm.

The calculation is as follows:

  • Candle + flame = 30mm
  • Aluminum tray height + TEC thickness = (50 + 5) = 55mm
  • Gap between TEC and flame = 15mm
  • Complete stand height = 100mm

With that in mind, ensure that your aluminum plate is about 430 x 100mm. 

Step 3- Build Support for Your Voltage Regulator

You can do this by cutting an aluminum strip, and the dimension can be 30 x 250mm. Then, proceed to ply the edges.

Consequently, the edges should fit the aluminum tray sides perfectly. Afterward, support the stand by gluing three corks. With this, you can glue your voltage regulator directly on the cork for insulation. 

Step 4- Link the TEC Wires to the Voltage Regulator

Typically, the black wire is negative while the red is cheerful. So, if you measure the voltage between TEC 8 and 4, a negative voltage will result. Hence, it means there’s inverted polarity because of the way you soldered the TEC pads initially.

Consequently, you have to make a reverse connection for the TEC pads to the voltage regulator.

Also, since the TEC works with temperature differences, use an aluminum plate. While you’re at it, bend the edges. 

That way, your TEC will get more heat from the candles. And your aluminum (160 x 120mm) should cover beyond the TEC plates. Then, glue the aluminum on the TEC with some thermal glue and let it dry. 

Step 5- Test Away

Add as many candles based on what your base can support. Then, light the candles and fix your tray.

Afterward, add some water and ice cubes—to make your water cooler. And cooler water translates to more energy. With this, you’ll’ notice a light on the LED connected to your voltage regulator. Consequently, the voltage on display will start increasing.

After that, you can wait for about two minutes for the setup to stabilize. After that, push the voltage regulator button. As a result, your filter will only allow 5V to pass through the regulator.

Wrapping Up

It’s’ possible to build DIY thermoelectric generators as long as you follomakingeps in this article. Also, building this free energy device is a good step in the right direction—especially if you’re’ a green advocate. Plus, it helps you convert temperature to electricity with ease.

So, what do you think about TEGs? Do you need help with setting up the device? Feel free to reach us. We’ll’ be glad to help.

Hommer
Hi, I am Hommer, the founder of WellPCB. So far we have more than 4,000 customers worldwide. Any questions you can feel free to contact me. Thanks in advance.

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