Advanced Uniflow Steam Engine | Hacker News Reader

Advanced Uniflow Steam Engine

kimmelsteam.com

43 pointsmhb9 comments

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For those who don't know, Dan Gelbart also has a wonderful series on prototyping.

[1] https://www.youtube.com/playlist?list=PLSGA1wWSdWaTXNhz_YkoP...

In my opinion Gelbarts explanation style always has a kind of Feynman vibe to it.

Also noteworthy is his recently uploaded shop tour video (the contents make up for the video and audio quality).

[1] https://www.youtube.com/watch?v=jbgdM35gZZA

There is now an updated shop tour video in higher quality.

https://www.youtube.com/watch?v=HWPYoE1SNnA

I worked on a Uniflow steam engine at a company about ten years ago. It was a four stage (compound) engine with double acting pistons; the first stage was about 60 bar IIRC and the fourth stage was entirely sub atmospheric (below 1 bar). So the pistons went from about 40 mm diameter to over a meter across.

The application was thermal storage with adjustable output (a steam engine can be turned up and down unlike a turbine which is pretty much tuned for constant conditions). Cheap PV killed it even though the overall lifetime operational and maintenance cost were estimated to be cheaper (with closer to constant performance levels).

You mean cheap PV with cheap batteries killed it?

I don't see how they could otherwise compare. Solar is cyclic and not a storage medium.

Yes, the batteries are still relatively expensive but the cost of PV plummeted so the overall system cost was lower.

What is "uniflow" about it?

Steam flows in one direction: intake and exhaust valves are on opposite ends of the direction of steam flow through the cylinder.

> In a conventional steam engine, the steam enters and is discharged through the same valve. This creates two problems. The first is that discharged steam needs a large port, which requires significant energy to operate against the pressure of the intake steam. The second problem is that discharged steam cools the intake valve and steam passages, leading to a significant energy loss.

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