A water cooled TEG with rated theoretical output of 200 watts
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Most of the documentation is by means of 3 videos in the instructions - 31 minutes in total. There are also CAD files and PCB files in the 'files' section for the engineering.
License: Attribution-NonCommercial-ShareAlike 2.5 Generic (CC BY-NC-SA 2.5)
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.
I was just looking up this project because I'm building TEG array as a side-project of my Metabolizer project, and it took me a sec to recognize your username and realize that you just followed me! I think we'd get along! I love this project- it's always nice to see folks do the hard work of trying something new, so that I can move more confidently forward! I've got a set of 6x TEGmart 22W 7.2V TEG modules that I've been kicking around for almost a year now, and just this week I got re-inspired and welded together some cooling blocks for them! I'm gonna try and add the module to scavenge heat from the engine exhaust. Keep up the good work! If you'd like to be be contributor on the Metabolizer, let me know and I'll add you!
-Sam
Thanks - I applied to join your project!
What is your opinion on:
a. using more modules with less temperature difference to cover more area of the stove.
b. using a radiator for "cooling" the coolant
c. the design of your heat exchanger: Some of the modules get the coolant that is already heated up to guide some degree from all the other modules. What was the temperature of the coolant?
Regards, Lars
Edit: Maybe it needs more heat-exchanger-surface per element?
The idea was to put the coolant very quickly through the heat exchanger with a powerful pump so it did not matter what the internal tappings did. I monitored the coolant water temp exiting the heat exchanger to check this. Radiators are a good idea, especially if they are outside in the cold and not in the warm house.
Agreed regarding coolant throughput, but I think your heat exchanger are too small.
Do you remember the temperature of the coolant water? Is the information in the videos and I missed it?
I was thinking about using radiators with this concept in house.
I think, the ideal is to put as much of the heat output of the stove through the elements as possible. You did kind of the opposite. You concentrated all elements on one spot.
You could very well be correct! It would be worth trying your idea - there was definitely SOMETHING wrong with my setup and I'm still not sure what it was. The project was starting to get rather expensive with regard to machining so I had to stop, but larger heat exchangers, with the TEGs separated, sounds worth trying - I struggled to get enough heat into the individual TEGs. If you live somewhere with cold winters, strongly recommend put the radiators outside as an extra 20 degrees temp differential will very much help.
I would rather not waste the heat. I am thinking about huge inside radiators with huge amount of coolant water.
I think that everywhere on the surface of the stove, where there is no TEG, the stove actually needs to be isolated/shielded.
The heat of the fire must not primarily be regulated by putting in more and more wood, but by controlling/managing the heat exchange of the stove.
Cheaper, less high-temperature-tolerant elements might work out better if one uses more of the cheaper elements instead of just a few expensive ones. This will also cover more surface of the stove.
Size and dimensions of the stove must be considered. I like your project very much, but 100W electricity out of 30kW heat is not good and the TEGs are not that bad.
Capt. Flatus O'Flaherty ☠
Commerical products already exist that do this... 30 watts for $429
https://thermoelectric-generator.com/product/teg-12-vdc-24-air/