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Energy from Natural Resources => solar systems homemade and commercial => Topic started by: andrew_snwl on February 25, 2009, 12:29:05 PM

Title: Revs of stirling engine???
Post by: andrew_snwl on February 25, 2009, 12:29:05 PM
Hi guys I am just about to determine some calculatons regards my school project. Is there anyone who has an idea how much revs per minute or second a typical stirling eninge can reach!!

(I'm using a satelite dish to reflct the suns rays)

thanks,

Andrew
Title: Re: Revs of stirling engine???
Post by: mindsweeper on February 26, 2009, 04:50:08 AM
Hi Andrew,

I don't think your engine is typical as you are using a dish to reflect the suns energy to a collector.

anyhow the 2nd law of thermodynamics comes into play and many factors like piston size, friction, collector size, heat displacement, air volume + many others all factor into the equation and is something I cannot help you with.

The Schmidt theory is one of the isothermal calculation methods for Stirling engines, you could search for that. NASA used it to some degree with very accurate results.

Any chance of a photo?

Good luck with the project.

EDIT: added table for calculations, I do not envy the challenge.
Title: Re: Revs of stirling engine???
Post by: andrew_snwl on February 26, 2009, 05:53:17 AM
Hey thanks for your info,

At the moment I am building my collector and the tutor advised me to find how much temperature would I reach with the dish and from there I could calculate the pressure at the hot end using thermodynamics calculatoins. From there I can use other equations to calculate the volume and hence come up with some dimensions.

But I need to know how much revolutions a stirling engine can reach ---- just a rough idea since i need this value to contyinue with my calculations. At least I could know the revs it can do in a minute in general.

Andrew
Title: Re: Revs of stirling engine???
Post by: robbie47 on February 26, 2009, 07:30:16 AM
Quote from: andrew_snwl on February 26, 2009, 05:53:17 AM

But I need to know how much revolutions a stirling engine can reach ---- just a rough idea since i need this value to contyinue with my calculations. At least I could know the revs it can do in a minute in general.

Two known companies use stirlings to generate electricity that can be coupled to the power grid.
For that you probably need stirling engines that can do 3000 - 3600 rpm.

In general it depends highly on what type of Stirling principle you are applying.
Speeds can be from 150 rpm to 3600 rmp
Have a loop at wikipedia