Here is an idea that might work with third-world tech:
Stick the cold side of the thermopile in a river.
Heat the hot side with a big fresnel lens molded out of
recycled glass.
Manual labor to keep the hot spot focused on the thermopile
as the sun moves.
Yes, this is something that could work reasonably well for some
things. I recall a device made back in the Cold war to run radios
(presumably to listen to Western propaganda). It consisted of a hood
for a kerosene lantern. The flame heated the interior and it had fins
all around it for the cold side. Supposedly ran a radio reasonably
well. But then today solar cells run a radio reasonably well and you
don't have to dip one end in the river either!
In case nobody knows it, thermocouples have such low output
(Millivolts) that they are useful only for temperature difference
measurements. However modern Peltier coolers are decently efficient
and operate both as coolers and power generators. These days the
commercial ones aren't especially expensive either. Perhaps too
expensive for third world use but can potentially last forever which
helps justify the cost. (roughly $20 a module, but I see there is
some new joint chinese-japanese company that is claiming massive
reduction in costs so that could make a difference)
