My actual plaything for this weekend is the LUFO "petroleum radio". This was made around the year 2000 and was intended to be a cheap lamp and radio for development countries with no proper electrical power. There was a belgian foundation that intended to sell it the same way as the "one laptop per child"-project (buy two and donate one).
The foundation went the same way as the laptop project but from time to time these chinese made lamps appear on the surplus market.
The lamp itself has a length of 40cm, looks like a big Feuerhand-lamp and has an AM/FM-radio in the base and the thermoelectric generator on top.
There should be a bigger version with a cookplate on top but I have never seen it in real life.
Compared to other lamps like Petromax or Feuerhand and such this lamp is really ugly and the material and colors are low end.
But it is funny to light the lamp and to wait about 10min for the radio to start. It has a telescopic antenna for FM and a ferrite for AM but the overall sensitivity of the receiver is not really good. Due to the big speaker the sound of my favoured station is nice and clear.
On the technical aspects:
The thermal electric generator is a solid-state semiconductor device and depends on the difference of temperature between the heater and the outer heat sink. The bigger the difference the bigger is the output voltage. If the lamp gets too hot (does so if one lightens it to bright or puts it in somewhere where the heat cannot be absorbed by a minimum of air) there is a decrease in the output voltage.
I wondered how bad the output power is. With medium light it makes only about 3V/100mA but I think it can be optimized by cooling the heat sink or making more light.
Commercially available thermal generators are not very efficient overall (about 5%) but have a low inner resistance so a standard device has to give 1-2A with a proper temperature gradient. Maybe that is the LUFOs problem, the cooling block gets heated by the flame after a while. Or the device is only a cheap chinese copy of a more sophisticated american generator.
These thermoelectric generators were common in the soviet union for remote beacons and, of course, for spaceships on both sides. The heat then comes from a glowing stick of plutonium and the cold, well, from outside...
The soviets had the most experience with that technology during the 50/60ies. They built some petroleum lamps with a generator to operate a tube radio during the 50ies but I have never seen it on a collectors meeting or somewhere else. But it looks amazing 50ies-like with a simple tube radio besides it.
That´s all for now, back to practical engineering
Some links or pictures are available on request.
maybe some of them were sold for 4 or 5 Marks on Friedrichshafen Hamfest flea market during the early 90's, it was full of soviet stuff!
