Temperature difference for usable Seebeck effect?

[Prismseed]

How much temperature difference do you need to get usable current from a pelteir under Seebeck effect? Even as miniscule as an led.

[mariuscivic]

The peltier module is good for curent. To reach 3-4V you need a direct flame on one surface and a good radiator on the other side.Keep in mind that the efficiency is only 2%. I'm also thinking using 20-30 modules to convert heat from exhaust to power a HHO cell

[Nink]

The peltier module is good for curent. To reach 3-4V you need a direct flame on one surface and a good radiator on the other side.Keep in mind that the efficiency is only 2%. I'm also thinking using 20-30 modules to convert heat from exhaust to power a HHO cell

That is a pretty good idea.  I have a stack of Tec1-12706 Peltiers they don't pump out a lot of power I was working on a project to harvest electricity with them but did not have a lot of success http://www.hebeiltd.com.cn/peltier.datasheet/TEC1-12706.pdf

[sm0ky2]

The peltier module is good for curent. To reach 3-4V you need a direct flame on one surface and a good radiator on the other side.Keep in mind that the efficiency is only 2%. I'm also thinking using 20-30 modules to convert heat from exhaust to power a HHO cell

there are two types of chip modules.
One designed for "cooling"
and one designed for power production.

Either unit will work in reverse, but each at a lower efficiency than its' intended use.
It is a function of their design.

If you use a "CPU Cooler" chip to produce power, it will do so poorly.
In the same manner, a power module will waste a lot of electricity trying to cool or heat something.

either way, the flat white square chips are a waste of time, or waste of energy depending on what you are doing with them.
(just my opinion on the issue)

The best I have found, are designed to go on the exhaust pipe of large semi trucks
(seebeck ring I think they call them?)
they have hundreds of thousands of junctions arranged in a circle, and made for heat to run through a pipe in the middle of the ring.
some of them go into the KW range.
new ones can be expensive ($2k - 10k)
but you can get them sometimes from truck graveyards, and repair guys.

also, theres a convection-style heat looping trick, we used back in the day to get more of your heat to run through the device
by circling the air through more than once while it cools.

Archer Quinn did a good rant on the effect back in 99' using a hair dryer, I'll try to dig it up later...

I like the idea of recycling exhaust power, the truckers have been doing it for years to power their sleeper cabins.

Not to mention all of the "fuel efficiency" equations, regarding HHO-injection into the air intake
---- are all based on using the battery to create the fuel additive !!!!
In your idea, this comes for free, so it is a pure increase in efficiency, any way you look at it.

[RomanEmpire]

I think those documents can be useful, Here: http://people.clarkson.edu/~bhelenbr/Research_Pages/Students_files/m.s.pdf , and Here: http://www.ijetae.com/files/Volume4Issue5/IJETAE_0514_104.pdf