hot Air Beam Engine with cooling and generator

Discussion on Stirling or "hot air" engines (all types)
Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Wed Dec 21, 2016 4:18 am

Hi Thanh - Is that one still being built - Looking good
Trevor

Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Wed Dec 21, 2016 8:16 pm

Well! nearly at the finish line now. The engine is now complete and working - Have added the lights with a small 3 phase alternator and as yet to make the radiator and/or cooling tower. To my surprise, this engine has quite a lot of power and I had to use a small flame from a spirit burner to slow it down. When on gas the engine just went overdrive and literarily shook the hell out of itself and nearly blew my lights - Heavens to bid! :big smile:
Anyway, it is begging to look good. - Pics attached
Trev
Attachments
4 - Small Flame Lots of Power.JPG
Had to change gas lamp to a small metho burner
4 - Small Flame Lots of Power.JPG (83.37 KiB) Viewed 1197 times
3 - All Lights Powered On.JPG
The LED's amperage together was 350mA @ 3.2 volts = 1.1 Watt
3 - All Lights Powered On.JPG (83.78 KiB) Viewed 1197 times
2 - 3 Phase Alternator.JPG
A small rewound 3 Phase rotor fan
2 - 3 Phase Alternator.JPG (58.28 KiB) Viewed 1197 times
1 - With power Plant.JPG
1 - With power Plant.JPG (90.92 KiB) Viewed 1197 times

thanh-cuibap
Posts: 147
Joined: Tue Sep 06, 2016 8:09 am
Location: Việt Nam

Re: hot Air Beam Engine with cooling and generator

Postby thanh-cuibap » Wed Dec 21, 2016 10:12 pm

Trevor : very nice !! very profession !! I like it...
Can you explain pump principle for me !!?
[img]
Top%20Altogether%20with%20Air%20Pump%20Fitted.jpg
[/img]
Thank trevor !!!
Attachments
Top Altogether with Air Pump Fitted.jpg
Top Altogether with Air Pump Fitted.jpg (120.06 KiB) Viewed 1195 times

Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Thu Dec 22, 2016 1:16 am

Hi Thanh - Trick little system of using a rubber diaphragm that is driven by the expanding and contraction of air within the displacer chamber. The first lot of photos show you the layout of the diaphragm. This is 25mm in diameter and works very well. Normally I would place the pump elsewhere but this time it suited me to place on top of the displacer chamber. - Photo attached
Trevor

Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Thu Dec 22, 2016 1:18 am

The layout is attached. - Trevor
Attachments
Air Diaphragm Water Pump.jpg
This is the layout - When building allow for the extra lost volume.
Air Diaphragm Water Pump.jpg (93.62 KiB) Viewed 1191 times

Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Thu Dec 22, 2016 1:53 am

This could be a good idea Thanh - Instead of using a forced fan feed for radiator I could just go and buy one of these for $40.00 landed at your door.
I reckon the air would flow through and cool the water easy enough if the radiator is placed horizontal - It would fit under my stand at least :laugh:

Trev
Attachments
high-flow-m.jpg
Radiator that could be used for hot air engine
high-flow-m.jpg (110.52 KiB) Viewed 1191 times

Aviator168
Posts: 308
Joined: Tue Feb 08, 2011 2:29 pm
Location: Brokeville, NY. USA

Re: hot Air Beam Engine with cooling and generator

Postby Aviator168 » Thu Dec 22, 2016 7:44 am

I reckon the air would flow through and cool the water easy enough if the radiator is placed horizontal

That has to depend on the water temperature and the amount of heat you plan to reject. For maximum efficiency, I reckon that the water temperature would be kept at close to 100*C. Having said that, if you work the thermal math upward, you will find the cold side air temperature of the engine is 150*C to 200*C at best (depending on other factors). Ever wonder why stirling engines are always lack of power? With common material out there, how many degrees can we raise the temperature?

thanh-cuibap
Posts: 147
Joined: Tue Sep 06, 2016 8:09 am
Location: Việt Nam

Re: hot Air Beam Engine with cooling and generator

Postby thanh-cuibap » Thu Dec 22, 2016 9:04 am

hi Trevor !! it finish
Attachments
Photo0062.jpg
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Photo0059.jpg
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Photo0058.jpg
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Photo0056.jpg
Photo0056.jpg (292.86 KiB) Viewed 1186 times
Photo0055.jpg
Photo0055.jpg (300.96 KiB) Viewed 1186 times

Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Thu Dec 22, 2016 10:50 pm

Love the paint work Thanh - The model looks absolutely stunning.
Hi Aviator - Re the temperature of the sterling engine. The earlier model I made with a fan attached (diaphragm type) used a radiator. First off, the heat source was a small pressurized all fuel type vaporizing burner that was adapted to using methylated spirits. When full on the water temperature going to the radiator through the coils was 70 Deg C. The temp from the air cooled radiator was 33 Deg C, It made quite a difference and the model ran for 5 hours at a market a few weeks back with no changes to temp, I have actually order one of those radiators to give it a try. I will let you know how it all works on this model on this thread.
Trevor

Aviator168
Posts: 308
Joined: Tue Feb 08, 2011 2:29 pm
Location: Brokeville, NY. USA

Re: hot Air Beam Engine with cooling and generator

Postby Aviator168 » Fri Dec 23, 2016 8:35 am

A few point on temperature. If you can get the water input/output temperature to the radiator and flow rate, you can find out heat rejection. If your engine is producing little power, this might just work.

Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Fri Dec 23, 2016 9:17 pm

Thanks Aviator - Another problem come up after running this engine for a couple of hours. The displacer started to full apart (made of steel wool) and jammed the intake to the piston. I think Ian told me this could happen using steel wool. Anyway, I made a stainless one (0.3mm wall thickness) that gave me a clearance of 1.5mmm wall to wall within the displacer chamber, however, after running with this I found the engine was lacking power compared to the steel wool one. I had to use a little more heat for the same amount of power. That said, I had then go to gas with better results. I really did want to use meths but could not produce enough heat to get the revs I wanted. With the gas and extra lights added I now get 2 watts at 4.5 volt - Pretty happy about that. Trev

Aviator168
Posts: 308
Joined: Tue Feb 08, 2011 2:29 pm
Location: Brokeville, NY. USA

Re: hot Air Beam Engine with cooling and generator

Postby Aviator168 » Sat Dec 24, 2016 6:07 pm

I made a stainless one (0.3mm wall thickness) that gave me a clearance of 1.5mmm wall to wall within the displacer chamber, however, after running with this I found the engine was lacking power compared to the steel wool one. I had to use a little more heat for the same amount of power.

A case a thermal short. It is the most difficult challenge in a stirling engine. In this case, the heat from the displacer's hot side walks to it's cold side, heating up the working fluid that is supposed to cool. A good beta engine is more difficult to build than an alpha.

Ian S C
Posts: 1970
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: hot Air Beam Engine with cooling and generator

Postby Ian S C » Mon Dec 26, 2016 2:07 am

Trev, there are a few things you could try with the steel wool displacer, (1)make a cylinder of s steel gauze that fits with clearance, make the end caps with holes (you can get perforated metal), fill the cylinder with with steel wool. (2) Sew through the stainless(as it is in your photo) with stainless wire length wise, and wind some of the wire around the S wool.
I have not had that much success with steel wool, perhaps I should have another go.
Ian S C

Trevor
Posts: 169
Joined: Sun Nov 06, 2016 4:07 am

Re: hot Air Beam Engine with cooling and generator

Postby Trevor » Mon Dec 26, 2016 4:27 am

Thanks Ian - I will eventually go back with the stainless wool as it seems to hold better. Steel wool is too fine and breaks up easily, even when I have tried A heavier grade, What I can tell you that in small models as I am building, that a regenerator makes a big difference (using wool that is). I really appreciate all the help people have given me. The radiator should arrive tomorrow and soon will have that hooked up and away we will go.....
Merry Christmas Ian and to all the others - Thank you, Trevor


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