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General Discussion / Stirling engine revolution
« on: March 17, 2020, 12:54:54 AM »
For all you folks that have machining capabilities, do you know how ridiculously easy it is to build a free piston stirling engine in the multi kilowatt capacity range? If the main reason you are interested in slow speed diesels is efficient and multi-fuel capable power generation, then the stirlings are definitely a better choice. Frankly, I'm tired of the ridiculous prices people are wanting for dilapidated slow speed diesels that need extensive repairs with only one or two sources of parts here in the US. No chance of any long life expectancies with pre-worn engines due to the limited nature of the repairs possible and those low quality parts currently available either.
Europe seems to be having a stirling revolution. Germany in particular. They have found that by using a stirling to directly drive a regular mechanical heat pump compressor using ordinary freon, and prudent use of counterflow heat exchangers, that a worse case COP of 1.9+ can be achieved! In carefully designed systems they are getting COP's over 2.5! That means for every 1000 btu's of fuel burned driving the stirling, you actually get 2,500 btu's of heat for the house! While it sounds like cheating the laws of physics, remember we are talking about HEAT PUMPS, which harvest heat from the outside in addition to using the heat input.
The EPA can't possibly gripe either without legally entrapping themselves because stirlings satisfy all sustainable energy carbon neutral desires. They can be powered by wood, garbage, landfill methane, any waste oils or fuels and anything that can be burned or that generates heat. Even solar concentrators are used. And to add to the benefit is the fact that most any fuel can be burned cleaner in a dedicated burner than in internal combustion, and considering most fuels rural folks are likely to burn, like wood are carbon neutral.
The theoretical efficiency is over 65% depending on design. You'll working miracles to get 35-40% from any slow speed diesel engine, especially with only 16 - 1 compression ratio's. And that would be only using good quality diesel fuel, not from any alternative fuel.
For me, I'm scrapping thoughts of buying any slow speed diesel. I'll just wait until I build a stirling.
Europe seems to be having a stirling revolution. Germany in particular. They have found that by using a stirling to directly drive a regular mechanical heat pump compressor using ordinary freon, and prudent use of counterflow heat exchangers, that a worse case COP of 1.9+ can be achieved! In carefully designed systems they are getting COP's over 2.5! That means for every 1000 btu's of fuel burned driving the stirling, you actually get 2,500 btu's of heat for the house! While it sounds like cheating the laws of physics, remember we are talking about HEAT PUMPS, which harvest heat from the outside in addition to using the heat input.
The EPA can't possibly gripe either without legally entrapping themselves because stirlings satisfy all sustainable energy carbon neutral desires. They can be powered by wood, garbage, landfill methane, any waste oils or fuels and anything that can be burned or that generates heat. Even solar concentrators are used. And to add to the benefit is the fact that most any fuel can be burned cleaner in a dedicated burner than in internal combustion, and considering most fuels rural folks are likely to burn, like wood are carbon neutral.
The theoretical efficiency is over 65% depending on design. You'll working miracles to get 35-40% from any slow speed diesel engine, especially with only 16 - 1 compression ratio's. And that would be only using good quality diesel fuel, not from any alternative fuel.
For me, I'm scrapping thoughts of buying any slow speed diesel. I'll just wait until I build a stirling.