1kw engine plans

Discussion on Stirling or "hot air" engines (all types)
Post Reply
johnmaster
Posts: 18
Joined: Thu Dec 27, 2012 2:13 pm

1kw engine plans

Post by johnmaster »

It appears my idea to turn a V8 ICE into a Stirling is just a disappointment waiting to happen, the work involved in trying to make it approach adequate could be better spent making something purpose built that actually works. Now that I have skimmed the NASA article and read Andy Ross' book "Making Stirling engines" I have a handle on the factors at play but I am having a hard time figuring out how to get started. Watched probably 100 youtube videos and read probably 100 threads so I am getting a handle on what materials to use where and why but I need to figure out what layout to use and how to size the components. I have ample fabrication skills and I have access to lathe and bridgeport as well as a cnc plasma I can program to make parts. I just want to get started in the right direction.

I am building a wood fired rocket mass heater similar to the link below except the mass will be 100 Gallons of water for hydronic heat in the home and shop. I am thinking now to not mess with putting the electricity produced from the stirling into the grid, since it would be easier to just make enough to circulate the water, run the blower fans, feed augers etc and keep the heating system from "costing" me anything in electricity. I could use a simple automotive alternator and battery and if the stirling were ever to quit I could simply hook up a small battery charger to take over during downtime.

So here is my heat source,

Image

http://www.richsoil.com/images/rocket-m ... mation.gif[/url]

I am thinking of replacing the barrel's lid with the stirling engine using either the whole surface and making a 2 ft dia pancake type or protruding the hot side piston down into the furnace chamber to get it into the hottest part of the rocket stove.
I like the basic concept of the Jim Dandy #6 but I'm having a hard time figuring out the arrangement of all of his components and what they are doing. Figuring where to start for sizing of the basic components and the layout is where I am stuck right now.

Any help or links to resources like plans to something like this would be appreciated. I would be glad to share anything I learn along the way as well. I could easily pressurise this up to shop air (100psig) or use an inert gas and regulator if pressures need to be even higher.
Geoff V
Posts: 121
Joined: Thu Apr 12, 2012 11:49 am

Re: 1kw engine plans

Post by Geoff V »

John

Am so pleased to see you are still keen after such disappointment with the V8.

I don't know of any plans for a 1Kw engine so you may well have to settle down on the drawing board and design around the facilities you have, which sound adequate for the task. I do believe the double acting gamma offers the best chance of realising 1Kw, for several practicle reasons, more later. The Jim Dandy#6 demonstrates that this level of output can be achieved, indeed exceed, but as it is a direct copy of the original Stirling engine of 1827 he has copied the system of levers and linkages typical of the period. Incidently there were three more iterations of the 1827 engine so the Rev R Stirlng clearly thought it worth developing and it powered an entire Foundry in Dundee Scotland for many years being replaced only because they didn't have access to Stainless steel. The linkage can be simplified as is evident by the following video.

http://youtu.be/LQJs5v8jV7w

The great advantage of this layout is that the working gas is sealed within the engine by three rod seals which means there is no need for a pressurised crankcase and adjustments to the phase angle can be made to the finished engine to maximise the power output.

Settling on the proportions for the displacer/piston bore and stroke can be established with some certainty once the heat exchanger configuration has been decided (tube or slots).

Have a look at the video and see what you think.

GeoffV
johnmaster
Posts: 18
Joined: Thu Dec 27, 2012 2:13 pm

Re: 1kw engine plans

Post by johnmaster »

Georgeous engine and thank you for taking the time to help. I like what you are saying about the gamma design, I will have to gear my searching in that direction and try to come up with my next round of nagging questions. I have been stuck on alpha's and the simple offset crank this whole time so now I need to try to envision how the linkages of the gamma design will work and how to get the heat from my furnace as directly to the hot side as possible.

Any other suggested reading or people to contact? I have that LTD engine book on the way but other than helping plant the concepts harder in my brain I think I am going to need to do more studying specifically geared toward gamma's.
Geoff V
Posts: 121
Joined: Thu Apr 12, 2012 11:49 am

Re: 1kw engine plans

Post by Geoff V »

John

I was going to suggest I send you some pictures by email of the work I've been involved with, because the file size limit on this Forum is quite restrictive, do you know how to send me a PM with your email address?

There are many books on the subject of SE's, unfortunately most are based on academic work which make many assumptions some of which fail to translate into the real world as we know it and can therefore be very misleading. Practicle experience and bench test results are by far the best sources of information and the Book by Andy Ross is a very good example of this. If you can find a copy, The Philips Stirling Engine by C.M.Hargreaves is very, very good.

GeoffV
johnmaster
Posts: 18
Joined: Thu Dec 27, 2012 2:13 pm

Re: 1kw engine plans

Post by johnmaster »

Found that book on amazon for $500, but my local librarian is trying to get a copy transferred to borrow from the milwaukee public library! I like the sleek looks of the linkage of the dual displacer gamma in the video, looks like very little friction involved.
vamoose
Posts: 267
Joined: Tue Jul 03, 2012 12:16 am
Location: Australia

Re: 1kw engine plans

Post by vamoose »

Hey johnmaster,

Saw this video and thought of you and your project...

http://www.youtube.com/watch?NR=1&v=obB ... =endscreen

vamoose
Post Reply