B How to calculate the efficiency of a steam engine?

[Pisica]

TL;DR Summary

efficiency of a steam engine

I am asking for help to find a calculation formula for a steam engine.
Does it matter if the steam engine is with a turbine or a piston?

 

[Dale]

What is the cycle you are using? The efficiency depends on both the working fluid and also the cycle.

If you don’t have a specific cycle in mind, then probably the most common one for steam engines is the Rankine cycle: https://en.m.wikipedia.org/wiki/Rankine_cycle

The Rankine cycle for steam achieves an efficiency of about 40% max.

 

[Chestermiller]

The efficiency is the work done per cycle divided by the heat added per cycle. For a turbine, it is the rate at which the turbine does work divided by the rate at which heat is added in the boiler (this neglects the work done to compress the liquid from the condenser).

 

[Pisica]

What is the cycle you are using? The efficiency depends on both the working fluid and also the cycle.

I want to test this.
But in a smaller version.

I'm looking for the highest possible efficiency, so which option would give the maximum yield.

I am looking for another working fluid, if you have any suggestions you can help me.

I want to recover the steam, return it to a liquid state by cooling and to be reused.

 

[Pisica]

Example:
A pneumatic screwdriver has the following characteristics:
100,000 rotations/minute?
6-8 bar
225Nm
0.5m3 air/min 500l air/ min
Late edit:
Something is wrong with this data.
It will give implausible efficiency.


Can we calculate the heat transformation efficiency in mechanical work?
The water is initially at 20 degrees C

 

[russ_watters]

Example:
A pneumatic screwdriver has the following characteristics:
100,000 rotations/minute?
6-8 bar
225Nm
0.5m3 air/min 500l air/ min
Late edit:
Something is wrong with this data.
It will give implausible efficiency.

Can we calculate the heat transformation efficiency in mechanical work?
The water is initially at 20 degrees C

If you're asking if you can calculate efficiency with that information; you can't. As @Chestermiller said, the general equation for efficiency is work out divided by heat in. Find (measure or calculate) those two things and divide.

At this point I'm not really sure what you're after though - you seem to be jumping around. If you want to build that and then measure the efficiency, just do it. It isn't clear what you actually want help with.

Note; there's risk in what the guy is doing in that video though; DO NOT build a non-rated/unprotected/uncontrolled pressure vessel. It needs to be rated for the working pressure and protected with a safety relief valve. You have a pretty significant risk of killing yourself if you don't do it right, and we won't allow discussion/assistance of you doing that.

 

[Dale]

You have a pretty significant risk of killing yourself if you don't do it right

@Pisica please read that quote multiple times. What is shown in the video is exceptionally dangerous. Pressure vessels are bombs, and have killed many people. The engineering and safety features are absolutely necessary. If you are not trained in this specific topic then you should not attempt it.

I am out. I do not want to help someone potentially maim or kill themselves or others. If you want to build a heat engine please find a different design that does not involve a potentially lethal pressure vessel.

 

[Pisica]

@Pisica please read that quote multiple times. What is shown in the video is exceptionally dangerous.

I assure you that I have not built and will not build anything of that kind

All I did was I posted a video that is not mine and invite to discussions.

That's exactly why I posted that video to discuss it.

That video is to discuss a working principle.
It is not to invite anyone to do something!.

I feel accused of trying to do something exactly like in that video.
As if I were a simple copier of a video.

When I said I wanted something similar, I meant a small educational kit for myself. To educate myself.


https://www.ministeam.com/products/wilesco-d9

Edit Conclusion!!!!!!!: I didn't do it, I won't do it and I don't recommend anyone to do what they saw in that video.
It is not an advertisement for the kit. I don't mean exactly it! I said something like that, that is, a similar kit.

 

[Pisica]

"please read that quote multiple times."
Am I to understand that I am not allowed to discuss in the context in which I have not built and will not build something dangerous?

Steam engine also means a harmless kit like the one presented before!
But it is easier to find a reason to close the discussion.

 

[russ_watters]

I assure you that I have not built and will not build anything of that kind

You said "I want to test this" under a link to that video.

I think at this point you should organize your thoughts and decide exactly what you want to do and need help with and explain it in clear detail.

 

[Dale]

I assure you that I have not built and will not build anything of that kind

All I did was I posted a video that is not mine and invite to discussions.

That's exactly why I posted that video to discuss it.

That video is to discuss a working principle.
It is not to invite anyone to do something!.

I feel accused of trying to do something exactly like in that video.
As if I were a simple copier of a video.

When I said I wanted something similar, I meant a small educational kit for myself. To educate myself.


https://www.ministeam.com/products/wilesco-d9

View attachment 359581
Edit Conclusion!!!!!!!: I didn't do it, I won't do it and I don't recommend anyone to do what they saw in that video.
It is not an advertisement for the kit. I don't mean exactly it! I said something like that, that is, a similar kit.

Thanks, that is good to know. I am actually exceptionally relieved to hear that.

DIY boilers scare me

"please read that quote multiple times."
Am I to understand that I am not allowed to discuss in the context in which I have not built and will not build something dangerous?

Steam engine also means a harmless kit like the one presented before!
But it is easier to find a reason to close the discussion.

I wasn’t speaking as a mentor intending to close the thread. I just didn’t want to participate in potentially maiming or killing someone.

I personally know an engineer whose pressure vessel ruptured, fatally injuring someone. I was there when he got the news. And he was a very capable engineer. A DIY pressure vessel is so much more dangerous.

So the above was not about what you are allowed to do but about what I was willing to participate in.