Thermo-Electricity

I'd use the waste heat to heat water.

A good ole boy would heat something else, and then condense part....

Had distant relatives, and school mates, who made shine.

Not in their houses, though.

Just google thermo electric generator. There are dozens of manufacturers on the web. Or if you are handy, you can build one yourself.

Leaving it well enough alone is a viable option, too.

Two points:

1. Yes it is possible. Do a search on "Peltier Effect Generator".
2. You will need more money than sense to have it perform anything useful for you from the heat exhaust of a wood stove. They are very expensive for what you get out of them in terms of useable power. You would likely do better boiling water and making a steam powered engine generator. From scratch.
   

An example of thermo-electricity is direct pilot flame impingement on a typical residential hot water heater's thermocouple (known as a "thermocoupler" by many in the trades), which generates sufficient DC current and voltage to hold-in the gas safety shutoff solenoid coil.

So, yes, electrical power can be generated from heat, but given the costs, as Jraef points out, it's not usually considered economically feasible.

The principle is good however the output is not - consider a different type of system

such as steam - it is dangerous and you need safety devices in place to stop it exploding from over preasure etc but the output is far more consistant which is what you want to drive a steam based motor which in turn will drive an alternator , you need to study the pricipals and power outputs and make sure safeties are installed

RobM

I thank all of you for the input. I did not think it would be cost effective, but did not want to spend a great deal of time and money trying to "re-invent the wheel". The system is already heating water for home heating. The system is non pressurized, max temp 185d/F. I've worked with boilers, gas/oil and solid fuel,and a solid fuel boiler needs a constant fireman-engineer. Way beyond anything I want to deal with. Again thanks.

RAMConsultant, excellent link, thaks for that!

We had a commercial T-E generator

Who was the mfg?

I have played around with using Peltier coolers running in reverse to make small TE power packs out of them and most of the newer high powered ones can in fact produce several watts of usable power without a a massive heat differential across them.

I made one from a old computer processor TE cooler that originally ran at about 20 watts input at 12 volts. With a pair of aluminum heatsinks epoxied to it I could set it in a pan of hot water and put ice shavings on the larger top heatsink and get about 1.5 volts at 1 - 1.5 amps load with it or the rough equivalent to what a good D size battery could put out.

I donated it to a local elementary schools science dept with a set of instructions on how to use it. The kids think its really neat how hot water and ice can make electricity just like a battery!

So yes with a bit of tinkering you can set up a TE generator with your hot flue gases as the heat source but you will need a good number of TE units to get any good levels of electrical power out of the process!

But where did the energy come from to make the ice???

We call it snow and for much of the year around here its free whether we want it or not!

Technically I think the energy to make it came from the water itself.