Letter Re: Thermoelectric Generators for Wood and Coal Stoves

Hello
You folks do an outstanding job of informing those who want to learn! I was just wondering if there was information about homemade thermocouples out there. I was watching my woodburner last night and it has one of those little fans sitting on top that start to spin when they get hot and was wondering if I could find plans to build a bigger version of the thermocouple. I envision something about the size of a briefcase . In a grid down situation this would be set on top the woodburner that would be going for heat and cooking and hopefully produce enough power to run a few lights and charge some batteries etc. Is there anyone who has an information source that could tell me how to go about building this?

Thank You, – Rich N.

JWR Replies: In my opinion thermoelectric generator (TEG) technology has been pitifully under-developed, given its potential for using otherwise wasted heat.

Here is a video of one experimenter’s project. And here is a commercial TEG site. I also found a web page for a commercially-built stovetop fan that is powered by thermoelectricity, marketed by Sportsman’s Guide.

I encourage readers to do some experimentation with TEGs. Given their irregular voltage output, it would of course be wise to route the power through a charge controller into a battery bank, for later use with a stable output. If nothing else, it will give you the means to trickle charge a few small batteries even when the only fuel you have available is firewood.