A house with an open fire. It has a back-boiler. The boiler has a small pump and this drives three radiators in other parts of the house. (*).
Out of interest, I was wondering about doing without the electricity to drive the pump, and instead running the pump from the energy in the fire. So, to me, the obvious trick is a heat engine to run the pump.
The question is; any clues/pointers as to where to start on a design or self-build ? The stuff I've turned up so far is either industrial scale, or lab/bench demonstration of principle engines. I think I need something inbetween.
(* there is also a conventional LPG gas central heating system, with usual electrical pumps, motor valves, electronic timer, thermostat, hot water cylinder, etc, but that's entirely separate. I have given thought to using the fire to top-up the hot water cylinder, rather than using LPG, but that again, is a different project, along with the solar thermal gain ideas, etc..).