I know it's Spring , But this is interesting

This might prove useful to some of you, a fan that will attach to the top of your Buddy Heater to better circulate warm air, no Batteries needed, it works by using heat to create the power needed, it has a "Thermal Electric Generation" device in its base, its the reverse of the solid state DC cooling devices Used in 12v fridges and coolers,
That's what thermal couples do, use heat to create power to open a gas valve,
This makes enough electrical power to drive 2 fans.

Fan for Heater or Fireplace

I was researching Stirling Engine Devices when i came across this