Stirling Engine Generator Mk4 (Rocket Stove!) Part 1

[@6strawb]

I think you've missed the main concept of a rocket stove with this. The initial fire where the wood burns is to pyrolise the wood and release the various gasses, you then need to introduce a bunch of oxygen at the base of the virtical flue which is where those gases burn creating the roar and heat. Just put a bunch of holes in the bottom of the flue and repeat the test, should get much hotter. Keep up the good work, you've made some impressive engines so far.

[@jimherchak7505]

I like the scale of your experiments and your "DAMN THE TORPEDOES" approach.

[@flatbrokefrank6482]

Great to see another engine on the drawing board!

[@Lechoslowianin]

This will be a very interesting project. There's a lot of work ahead of you. Good luck ​

[@rutgerjohanson1846]

Looking forward to see it in action

[@peterford436]

Excellent backyard British engineering...

[@David_Mash]

Linear generator. Build the cold side with a magnet piston and the cylinder made of a coil in resin

[@not.so.ai-01]

How cold is the "cold side"? I'd worry about magnets getting demagnetized from the heat, quick googling shows that it only takes 80C to permanently damage regular neodymium magnets.

[@David_Mash]

@@not.so.ai-01 keep searching to understand why magnets lose their function with heat. Magnets can be manufactured for higher heat as well.

[@TurbineTed]

Hi Shane It's great to see somebody building big Stirling engines instead of little models (like me!) but please be very careful if you decide to use Viton rubber for diaphragm's. I have worked with Viton 'O' rings for many years and if repair work was needed on a piece of equipment which had been in a fire then extreme caution is required when handling the stuff. Personally I would never consider using the stuff any where near a high temperature engine. Below is a warning from somewhere (I can't remember where, but I copied it some time ago, to warn new commers to the job). "The brand name VITON can be found in seals, gaskets, 'O' rings, drive belts and electrical items. VITON, is a Fluoroelastomer (a synthetic rubber like material containing fluorine) and when used under their design conditions are perfectly satisfactory and safe. However, when subjected to high temperatures (Above 600 degrees C) this material can partially decompose into hydrofluoric acid! The burned appearance of this substance is that of a black sticky mass. The Hydrofluoric acid may appear as a clear liquid on top of the burnt component. Hydrofluoric Acid is extremely corrosive and IMMPOSSIBLE to remove, particularly on human tissue. Exposure can be difficult to detect, because in its diluted form does not cause immediate burning or stinging on contact. The 1st symptoms may show hours later as a bleached area on the skin. Unfortunately, by this time the acid has already leached into the internal tissues and eaten away at the bone mass. At this point the exposed area may need to be amputated!! It is recommended that before carrying out any work on fire damaged equipment, a check should be made to determine if any drive belts, seals, gaskets, etc. have suffered decomposition. Do not touch components with bare skin! Wear neoprene gloves. Decontaminate with detergent solution."

[@ShanePomeroy]

Thankyou for the warning!! I'm planning for the temp of the seal to never rise above safe levels but I will proceed with extreme caution! The other material I was looking at was silicon rubber. All the best

[@TurbineTed]

I think silicon is a much better idea although it probably has its own draw backs. I have seen silicon seals wrapped around 400 deg C steam pipes which seemed to work OK.

[@perrymattes4285]

Hey Shane for your heat exchanger look up heat pipes. They are used to move heat very efficiently. They are a kind of heat engine unto them selves. They move heat from one place to another. Basically sealed copper tubes with alcohol and either pressure or vacuum and wick to pull the liquid to the heat.

[@ShanePomeroy]

I remember you mentioning these back along. It might be a solution to deal with awkward arrangements like engines with multiple cylinders, etc. Trying to incorporate a burner in the right place always seems problematic! I wonder how easy they are to build?

[@oddzc]

You can buy heatpipes and solder them in place

[@dieguerrero]

Can't wait to see the following videos! Thanks for this new series of stirling build. Best of luck!!!

[@djkutilak]

I see one problem with this design. In hot side exchenger is too much dead space. Maybe if you do this part from lots of small tubes it can be work great

[@unusualfabrication9937]

Nice, right back to it after the previous one found a new home. love these build & development videos

[@3DRobot69]

I'm looking forward for this build! You could design something that adds dead volume to the engine, that would then be used as a way of controlling the speed.

[@ShanePomeroy]

Once I get it running that would be a fun experiment. Speed control is always problematic!

[@sunoncream1118]

@@ShanePomeroy speed control not anymore a problem if u can start a fully enclose cranck case with the electric generator.. will be just more or less power : recover scrap 12v battery from autorepair §they usualy hold 200 usable watt and if good enough will eat 5 to 10 ampere when recharging ... meaning 10 of them should normaly absorb ur 500 watt produced then they act as capacitor/battery to deliver more or less power without having to control the engine speed... (dont try too much to climb the hill if there is a tunnel that get u where u want easier)

[@sunoncream1118]

car starter : block it into engaged position ( a weld dot maybe? ) tweak pignon seize to match ideal engine rpm .. should be cheap and not too much work and u have the starter and generator .. ?

[@stuartdean4620]

Was thinking about diaphragms and your piston arrangement thinking about using perhaps old tires or lorry, suspension, airbags

[@ShanePomeroy]

I'll look into that. The diaphragms are giving me some sleepless nights!

[@stuartdean4620]

@@ShanePomeroy I also work on Mob mobility scooters and we have Tires of weird sizes. If I can help in. Anyway let me know the sizes you need

[@The-Stirling-Power-Project]

Heres one vote for a Gamma build!

[@ShanePomeroy]

I would like to build a gamma engine but I can't think of an easy way to include big heat exchangers at a reasonable cost. I might be wrong. All the best

[@LittleAussieRockets]

Okay I'm excited!

[@johnwynne-qx6br]

Good to see a new build taking place. Look forward to your future videos.

[@paulbenkovitz2061]

If I was building it I would have the crank and the pistons on the same plane to simplify rod design. The drop of temperature you saw could have been the stove starving for air. I bet testing with a chimney would result in different measurements.

[@ShanePomeroy]

I'm wondering if the temperature drop was the reduced radiant heat as it went up. I think a chimney is a good idea, cheers

[@Ian.Gostling]

Terrific!

[@janposthumus8735]

Thanks for the update!

[@peacefulscrimp5183]

Great video 👍

[@sharedinventions]

I'm not completely sure on this, but I believe rocket stoves should have the hottest point at the top. So you might not have the perfect parameters. Further more, you must not cool the raiser part with heat exchanger of the stove as it will break the "rocket" effect. In other words: you should put the heat exchanger on the top.

[@ShanePomeroy]

I'm wondering if the higher temps I was measuring at the bottom was due to the radiant heat lower down. I'm edging towards heat exchanger at the top, many thanks

[@perrymattes4285]

Yay!!!

[@StanislavZachazevski]

Like before seeing a video. My gift with some anodised aluminium and graphite filled ptfe still is waiting for you :) I think i have 100x5 and 150x5 tube.

[@ShanePomeroy]

Very kind of you stanilav. I haven't quite got to the point of finalising internal dimensions yet. I was hoping of sending them your way for analysis?

[@StanislavZachazevski]

Anytime, you know it. @@ShanePomeroy

[@briandalrymple9986]

Like the others with comments, I too am looking forward to the next stage and video. I am concerned about the temperature you reckon you will reach. Are you aiming to put your heat collector in the actual flame? Deep red fire is about 600-800° Celsius (1112-1800° Fahrenheit), orange-yellow is around 1100° Celsius (2012° Fahrenheit). In a rocket stove, expect red hot metal heat to be present very easily as the air flow at the fuel flame can easily exceed 1200°C and even if the flame colour is red where the wood gasses are burning and should indicate only 6-800° C, the actual exhaust temperature may be well above safe limits for where the collector is situated. It may pay to consider a rudimentary air cooling damping system, perhaps injecting a controlled cooler volume of air near the heat collector to mitigate this problem. Perhaps a double skinned collector with the ability to control the actual inner collector surface temperature. Keep up the searching for a successful “new”, model. Brian from NZ.

[@ShanePomeroy]

Thankyou for your analysis Brian. I to have concerns about melting metal heat exchangers! I'm probably going to place it at the top of the riser but also don't want to compromise the power output. decisions, decisions! Air cooling sounds good Thankyou

[@briandalrymple9986]

@@ShanePomeroy Hi Shane, I am not too familiar with the actual temperature you need for your Stirling engine to operate. I have built rocket stoves and fitted one on an oven and cooked bread successfully, so am familiar enough with how they operate. What actual temperature are you hoping to sustainably achieve? Cheers

[@ShanePomeroy]

I've thought about what you've said and I'll be placing the heat exchanger higher up. I would of thought 600 degrees C is about right.

[@briandalrymple9986]

@@ShanePomeroy Try this link. www.engr.colostate.edu/~marchese/mech337-10/epri.pdf It’s a bit of reading for sure, but you may find it interesting. 🤔 Brian

[@julmaj1479]

Do you have any hints about cylinders. Where to obtain some usable parts. Cylinder and piston *

[@ShanePomeroy]

Hi, I've only really experimented with what is in my previous video's and these are extremely basic designs to say the least. I don't have any secret sources of parts but I did think that a stainless tube (that don't really have weld ridges inside) coupled with a PTFE lip seal piston might be worth a go

[@julmaj1479]

@@ShanePomeroy thanks a lot. Looking forward for your next designs!

[@corashy1950]

I think this guy. Is making the engines to discourage other's and make it seem as if it has no hope! I have a friend that built 1 of his engines. No this guy couldn't get an alternator to work! Same design we were able to power 6000 watt Permanent Magnet generator head?? Either he isn't paying any attention or he hiding something. 😊

[@caprottigiuseppe]

Che rendimento ha?? Con 1 litro di gasolio quanti kWh può produrre? Grazie

[@davidhollman34]

Can I buy an engine from you ?

[@ShanePomeroy]

Yes, if it works! If this one works, I could always build one to your spec / power requirements?

[@JuanCastellnouBarcelo]

😢