Sterling motor - anyone have any formulas

If you ever decide to build up anything, that means you really know a lot about it and have undertaken a lot of research before starting to even think about it.

But, when you ask questions before starting to build then you do not have the slightest idea to what you are building.

Example:(1)

I build "Condensate power Pump" to pump 100C condensate to maximum 135 ft height.It has no moving part and no maintenance and requires no electricity to pump.Knowing they are also available with over 15 leading manufacturers so I made mine with a bigger body with more discharge capacity for the same size.

Example:(2)

I build Flash Condensing Deaerator for Feed Tank.

On each I researched and collected datas/documents etc., for over 2-3 years prior building.

You cannot simply ask questions before building something which has already being build. You can build , operate and if you run into operational problem then you can seek solution and we will give you.

Aww, shame on you ducon, man wouldn't have invented much if he'd waited till he had all the answers before he started.

I'm sure there are examples in reference texts like 'Rodgers and Mayhew' - our college text. Try Ebay for some engineering reference material - reckon youll have plenty reading matter in no time.

U are right. That's exactly what I want to tell him. I am not against building anything but when he is going into building that means he is fully confident about himself and he has had had a lot of reading materials on the particular item.

Once he has build and encountering problem then the best part starts when we all gather around to put in our efforts to help out.

One best example is the vacuum/ejector thread where Bell the Cat and other guys really put in some excellent recomendations and the effort of the other person in counter checking each one's replies into practical application.Very soon we will see results into an improved ejector system.

Hi ducon,

I believe fishpipes has the confidence. Maybe he has enough mechanical skills to build a Stirling Engine from a good drawing and instructions (available on the internet).

What he doesn't have is enough engineering knowhow to calculate how powerful his project will be. With this knowledge, he could:

• determine if he could make it more efficient
• figure out how to build an engine that would fit an application
• design an engine to last or operate safely
• etc.

I've built things that I didn't really have much knowledge about. With a good drawing and/or instructions, anyone with some mechanical dexterity can build a Stirling Engine. Besides I don't think he wants to take 2-3 years before building it.

Of course, some things are better studied first before going into, such as building a nuclear reactor in your backyard (story here).

A Stirling Engine is a fairly simple project. The math is more complicated, which I, unfortunately, cannot provide any help.

Sorry Del the Cat and Ried/GER & others.

And here is the result we all were waiting for:

"Well, I connected a larger diameter tube on the suction port and wow, huge difference, 7X more chemical entrailement. The larger diameter tube, coupled with some minor orifice dimensional changes and a shorter barrel have together increased performance ten fold. Thank you guys for the ideas and information provided. Yea, I think it's about time I sign up on the site as well now. Iv'e been using it for about 6 months a s a guest. Again, thank you." Guest

We had a thread on sterling motors a few months ago! Check it out, There are many sites! I had a good look into it and found nearly all the info needed to build one! (Not that I wanted to build one mind, but the philosophy behind it!)

"I'm working on building a sterling motor out of off the shelf parts. But does anyone know the calculations needed to figure what kind of power you can get out of any given displacment? By the way I'm building an alpha type machine."

There is much more to it than simply assembling "off the shelf" parts.

I would suggest you read up on Stirling Engines before embarking on the fabrication of a first attempt. The books on design of such are for the most part out of print and expensive IF you can find them. Air Engines by Finkelstein & Organ, ASME Press is only a few years old. $100 US from ASME or Amazon. In addition there are a number of other books that are needed to provide the necessary theory to achieve a successful desigh.

Go to <stirlingengine.com>, click on image of "How I Built a 5-HP Stirling Engine" by Dr. Lockwood. You can download Chapter 6 in total with many photos.

The foregoing is NOT to throw cold water on your plans but to suggest that you must be realistic in your expectations and realize it is not an easy road to travel.

Mr.Stirling Stan - with very due respect, Are you related to the inventor of "Sterling" Motor? All books & sites are with your first name.If you are then please help him out.

The Stirling Engine was conceived initially by a Scot, one Dr. Robert Stirling, who passed away on 6th June 1878. CR4 wasn't invented then. Here's a brief insight:

http://en.wikipedia.org/wiki/Robert_Stirling

I know he has nothing to do with the Sterling silver

Sorry, what was that about stealing silver??

SSt not so loud. Crabtree is listing.

Gentlemen, please remember that the name Sterling refers to British money and a certain quality of silver etc., the name Stirling refers to a Reverend Stirling, who designed the first Stirling motors in the beginning of the 19th century......

Stirling's air engine (as it is referred to in early text books - see hot air engine history) was invented by Reverend Dr Robert Stirling and patented by him in 1816.

Please reference Wikipedia at:-

http://en.wikipedia.org/wiki/Stirling_engine

for further infos.

I hope this helps all concerned!!

Hi Stirling Stan, I wish you would write the correct spelling; "Stirling engine". Sterling is a grade of silver, 925% silver to be exact. Spencer.

Are you sure about the percentage?

Hi Gwen, Yes I am, I do happen to be a gemmologist. Spencer.

Spencer,

You might be a Gemmologist, but I'm a Mechanical engineer, with quite some knowledge of alloy's, more on copper but anyway, your alloy simply can't be made.

Gwen

Hi Gwen, Sorry but there shold have been a point between the 2 and the five. Corrected it is 92.5%, the rest is copper and nikel. Spencer.

Joke, I was worring you kicked out the copper.

g

there is a boook - Stirling Engines by Reader and Hooper. they supply everything you need to know.

Rodgers and Mayhew's book as well as Stirling Engines by Reader and Hooper would likely be of help IF available. Locating a copy of either one published about 20/25 years ago in the UK would be difficult if not nearly impossible to locate and get delivered to mid USA.

There is a multitude of resources on the internet if you can invest the time in locating them. Visit <notscar.wik.is> for lists of website devoted to Stirling and hot air engines!

As stated before a decent literature search is the first step.

Start with a simple search term in Google.

Then you can refine.

To find real interesting data you can add NASA to the search term, they have done fantastic research on Stirling engines and luckily the results are nicely published (at least for some projects)

Start here: http://www.grc.nasa.gov/WWW/tmsb/stirling.html

Nasa has some very nice publications, some quite old but still very valid.

I wish you good luck and keep us posted with the results of your experiments.

Gwen

Hi fishpipes, Here is a simple equation worked out by William Beale who discovered many years ago that the output of many Stirling engines was aproximate to; P = 0.015p x f x Vo. Where P = engine power in (watts), p = mean cycle pressure in (bar), f = cycle frequency or engine speed in (hertz), Vo = diplacement of power piston (cubic centimeters). Then there is the Carnot efficiency, this can be calculated at a reasonable 40 - 45%, so the thermal efficency of a stirling engine can be calculated thus; n = Power output/Heat supplied = 0.40 (Tmax-Tmin/Tmax). I hope that this will help you in your endevoures. Spencer.

Give this dude his formula,

Carnot law tells that :

efficiency = 1- (Temp (low)/ Temp (high))

(temperature needs to be in Kelvin, °C = Centigrade) => x°C +273= K

If there is an environment temperature 20°C in Kelvin 20+273=293K

If you want a efficiency of 40% than you need a temperature of 488K = 215°C this is a theoretical efficiency, practical it will be less than 20-50% of it.

Compare to an petrol engine it burns around 1000°C and we have an efficiency of 25%

Hey Farman, can you join our user group?

Before it's to late

I know this can become complex if Ives can't find a solution.

Hi Farman, The temperature of the combustion chamber I use on my stirling engines is about 1000K, this is about the normal for todays modern stirling engines. The lower temperatures of the cool end are about 300K. Spencer.

The 5 questions.

#1. Application.

#2. What have you seen that has the same size, weight, and used like what you are building.

#3. Go to someone that has built something like you want or to a farm tractor salvage yard that can give you a complete package from a tractor or combine.

#4. Get the cash ready.

#5 Call me with your answers. 800 828 1656.. Tom Silver.

The Big Question is! Do you plan to drive this on the road?

There are Fed. Regulations about the max speed of a _______ of about 45 MPH for hydrostatic controlled applications.

Danfoss offers a tech Manual.

Please include a web-link

Thanks everyone. I've learned a lot and I think I have a better handle on how to learn more. I have fallen in love the the Stirling engine and wish that someone built one that the average handyman/farmer type person could really use. All I have been able to find out there are toys and expensive toys at that. If you can't buy what you want then you have to figure out how to build it. And thats what I want to do.

So again thank you.

Great enterprise fishpipes (fishpipes??? heard of fishplates?), power to your elbow! Keep everyone up to date with progress.

If you can't buy what you want then you have to figure out how to build it. And thats what I want to do.

Fishpipes - don't get disheartened with criticism. Keep us posted on development.

New News - I am now trying to build Boiler Economizer Cylindrical type with flexible finned-tubes. I am collecting data for the last 2 years. I have imported "serpent" type flexible finned-tube 2" about 25M length .The only problem I am facing is on the by-pass (in event the tubes leak ) without a diverter. I am facing criticism a lot but like you, if succeed, it will cost me 20% and I can market it at still 40% less than the imported.

I personally would love to see more done with the Stirling Engine, maybe with reflected Sun rays for countries where the Sun shines.....

By the way, there is a company that sells a mini Stirling made of paper and aluminium that runs on a hot cup of coffee for $49....

http://www.stirlingengine.com/ecommerce/product.tcl?product_id=87

....there is even a video at:-

http://www.stirlingengine.com/mm5flash/mm5flash.html

I wish you well in your endeavours, keep us posted please.

I recall seeing an adv. someplace where the hot cup of coffee is stirred automatically. You just put in sugar and it does the rest. This is to help save your energy in doing the stirring. Honest - no joke! I belive a stir-`ling' motor under the cup.

Just connect a teaspoon, and it's away!

Gr8. The animation is EXCELLENT.

I've only registered on the site in the last couple of days.

Have a look at

http://www.stirlingengine.fr/principles.php

the website includes a spreadsheet that might help.

I note that your query was dated 2007. Have you progressed on bulding the engine? You can contact me on robert.knotts@btinternet.com

Regards

RobK