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# Linear vs rotary power generation

## Linear vs rotary power generation

(OP)
Hi guys not sure if this is the correct place to post this question but here goes
Which is more efficient rotary electricity generation or linear power generation (e.g. by NASA stirling engine)
Have seen some articles saying that linear generation is more efficient from the power put in to power out.
Upwards of 41%+ efficient according to one company's research
Thanks for the info

### RE: Linear vs rotary power generation

Conversion of linear to rotary energy and the reverse are fairly efficient mechanical processes so it is much of a muchness.

je suis charlie

### RE: Linear vs rotary power generation

Large generators - obviously, rotary in design - are already mid-to-high-nineties percent efficient, which doesn't leave a lot of wiggle room for improvement.

If you've ever had a lawnmower/motorcycle/small automotive piston engine apart to rebuild it, it takes finger power to operate the connecting-rod-and-crankshaft conversion of linear to rotary power manually. The piston rings have much more friction in them.

Making a rotary generator produce 3-phase power is simple. Making a linear generator do it is ... not so simple.

For a very large scale generator, making a rotary generator produce standard 50 Hz or 60 Hz (depending on where you are) alternating current is a simple matter of designing the rotor and stator with multiple poles. Doing that with a linear generator is ... not so simple. You are stuck with 3000 or 3600 cycles per minute. Unless you let it make whatever other frequency it wants to make, rectify to DC, and use an inverter to make 50/60 Hz out of it. A 1000 MW inverter might be ... a little expensive.

Inventors seem to have this persistent mind-set that conversion between reciprocating and rotating motion is a horribly inefficient process, even though it isn't.

Bottom line ... NOPE.

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