These videos document my first attempts at generating electricity from a thermoelectric peltier device in 2012. The TEG that I used is a high powered unit able to withstand high temperatures and specially made for electricity generation.

Details of the TEG modules can be found in the files section here: https://hackaday.io/project/107767/files

A ten unit Thermoelectric generator system is shown being constructed and then fitted to a wood burner. The theoretical maximum output is 200 watts. The video shows how the generator was put together and how the wood burner was modified to get maximum heat through the TEGs. The TEGs themselves are able to withstand a constant 325 degrees C on the hot side and require plenty of heat to get the 20 watts that each of them are capable of producing.

In part 3 we successfully generate a significant amount of energy from the woodburning stove. In the first session, a circulation pump, a fan and 10 x 10 watt flood lights are powered up. In the second session, we attempt to get a more balanced load wired up to the tegs and measure a noticable increase in power output. The 10 tegs are wired up in 2 parallel strings and, from the manufacturer's specification, the optimum output voltage is 14.4v . The nearest that we manage is 13.8v, at which we generate 120 watts. The specifications suggest that 200 watts is possible when the load is matched.

There are CAD files in the files section for the 10 TEG version, but for simplicity of demonstrating the procedure I've documented building a single TEG version.

Parts:

• Thermoelectric power generator TEG module (GM250 449 )
• ...... buy direct from China at: www.thermonamic.com/
• Aluminium block 102 x 115 x 20 mm
• Steel block 102 x 115 x 10 mm
• 1/4" BSP blanks x 6 of
• 1/4" BSP male stud push fit pneumatic fittings for 10 mm pipe x 2 of (See photo above)
• 5 mm Hex bolts x 40 mm x 2 of
• 25 litre water butt
• OD 10 mm ID 8 mm nylon pneumatic pipe
• 12V water pump
• 12V LEDs, 1 watt x 20 of

Tools:

• 1/4" threading tap
• 5 mm metric coarse threading tap
• Drill 11.5 mm
• Drill 5.5 mm
• Drill 4.2 mm
• Drill press
• Torque wrench
• MIG welder
• Plasma cutter / Grinder with cutting discs

Use the engineering drawing to produce internal coolant passage ways in the aluminium block. I ended up drilling all the way through to the other side and using more of the 1/4" blanks.

Connect the 1/4" pipe fittings to the block and plumb in the pump. Add antifreeze to the water in the water butt if it's likely to get cold at all.

To create a 'sandwich' with the hot block (steel block), the TEG and the cooling block, drill and tap holes in the steel block for the 5mm bolts.

Weld the hot block into the side of the wood burner and recreate the TEG sandwich, tightening the bolts up with a torque wrench (see attached file).

Connect up LEDs on the TEG, turn on the pump, light the wood burner and off you go!

If you really must build the 10 TEG generator, the photo above shows what is involved.

The maximum recorded power from the TEGs was 130 watts with the wood burner running at full power - I'd guess it was producing about 30Kw of heat. The amount of fuel being used to get 130 watts of electricity was a lot greater than I had imagined and, in terms of cost of fuel and value of electricity produced, the ratio is about 250:1.

The 10 TEG unit was quite expensive to build which, for me at least, would have been ok if I could run the burner at 5 Kw, but to run it at 30 Kw was not practical.

A better way to use these TEGs would be to install them on a more sophisticated 'Clean burn' gasifier furnace / rocket stove which operate at much higher temperatures and efficiency. Not the sort of thing you'd want in your living room though!