What would happen if we combined current pellet stove technology with a Stirling engine through an outside wall?
In Theory, A Stirling engine works on a difference of temperature. For many rural homes there is great expense in developing and sustaining power lines. These homes are already heating from an inside source, and create a difference of temperature, depending on the proximity to the firebox of at least 2X. If developed as a mobile stove, you could glean a mobile power source only dependant on supplying a small chamber with fuel.
Such an engine would be able to sustain on green fuels as well if heating an area wasn't a factor.
It might even pay for itself in an AC situation where the thermal difference is reversed.
Why haven't we put a power source in every appartment using electric fuel?