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Well, I'm in Sweden which seems to be somewhat of a Stirling engine knowledge centre with Kockums (a shipyard) using them for "undetectable" submarines and Swed

Well, I'm in Sweden which seems to be somewhat of a Stirling engine knowledge centre with Kockums (a shipyard) using them for "undetectable" submarines and Swedish Stirling [1] (a company based around Kockums' Stirling technology) using them for CHP installations running off flare gas and other waste gases for heat and power. That's all fine but their products are aimed at small-scale utilities and industry, not individual farm or single-household domestic applications. There are plenty of toy Stirling engines around and clearly also plenty of large-scale ones but I have not found one in the 15-30 kW range I'm aiming for. It would be possible to build one but it would be much easier to get one off the shelf somewhere. Another option I've been toying with is a small gas turbine [2] which should increase reliability and lower maintenance over a piston ICE - which I assume is the reason you don't like ICEs in these applications?. Has APL considered that route? [1] https://swedishstirling.com/ https://swedishstirling.com/ [2] https://www.sciencedirect.com/topics/engineering/micro-gas-turbine https://www.sciencedirect.com/topics/engineering/micro-gas-t...

nanomonkey 4y ago
Yes, we had a small turbine, they aren't cheap or as easily serviceable as piston ICE generators. The biggest problem with turbines and any internal combustion engine is that your fuel needs to be clean. With woodgas, you often have particulates, or volatile gases that will precipitate out as temperature and pressures fluctuate within the engine. This fine soot and tar gas can cause fouling over time. For this reason, I think externally combusted engines (Stirlings or steam) are the way to go for a small scale simple cogeneration plant.
- the_third_wave 4y ago
  That would make it possible to use/modify any of the existing gasifying wood boilers - something like these by Atmos [1] - for this purpose by e.g. replacing the bottom ceramic inset for one which includes either the hot side of a Stirling engine or a heat exchanger for such. Steam under enough pressure to drive a turbine... while it might sound promising it would involve a whole new host of regulations which would increase the price as well as yearly conformity checks, at least where I have lived - the Netherlands and Sweden. This might not be viable for these small-scale applications. [1] https://www.atmos.eu/english/kotle-001-kotle-na-drevo https://www.atmos.eu/english/kotle-001-kotle-na-drevo

nanomonkey 4y ago

Yes, we had a small turbine, they aren't cheap or as easily serviceable as piston ICE generators. The biggest problem with turbines and any internal combustion engine is that your fuel needs to be clean. With woodgas, you often have particulates, or volatile gases that will precipitate out as temperature and pressures fluctuate within the engine. This fine soot and tar gas can cause fouling over time. For this reason, I think externally combusted engines (Stirlings or steam) are the way to go for a small scale simple cogeneration plant.

the_third_wave 4y ago
That would make it possible to use/modify any of the existing gasifying wood boilers - something like these by Atmos [1] - for this purpose by e.g. replacing the bottom ceramic inset for one which includes either the hot side of a Stirling engine or a heat exchanger for such. Steam under enough pressure to drive a turbine... while it might sound promising it would involve a whole new host of regulations which would increase the price as well as yearly conformity checks, at least where I have lived - the Netherlands and Sweden. This might not be viable for these small-scale applications. [1] https://www.atmos.eu/english/kotle-001-kotle-na-drevo https://www.atmos.eu/english/kotle-001-kotle-na-drevo