Introduction: Building a Low Cost Stirling Engine for Power Generation

Before I will start my Instructables want to emphasize that this is not a finish project and still going on as of the moment I'm creating this Instructables. I already spent more than 3 months making this though I am near to realization still it is not enough to finish the whole system on time. None the less although not finish, this Instructables will be enough for you to build a low cost running Stirling engine and more.

The aim of these Instructables is to build a working Stirling engine that could be coupled with generator for electric generation like this one or this awesome! but not that kind, we will be building a much much .... much simple one. Honestly while building this project I want to find the best materials available but then my budget restrict me from doing it. Due to financial constraint, this Instructables became a research on building a Stirling engine having always in mind the cost (most affordable), availability of materials locally and that it could be build using the most basic tools available (poor-man's tools).

Here is my guide to make it run in few attempts. Hope you will like my Instructables please vote for it. If you find it useful please hit favorite and share.Thank you.

Step 1: Understanding the Engine

What is Stirling Engine? A Stirling engine is a heat engine that operates by cyclic compression and expansion of air or other gas (the working fluid) at different temperatures, such that there is a net conversion of heat energy to mechanical work. "as per wiki" for more info check this . Understanding how Stirling engine is easy as explained in this site but making it run is a different story.

The Stirling engine that I made is beta type where the displacer and piston is in the same cylinder. There are many types of Stirling engine but all works in the same process. It relies on expansion and contraction of gas inside a confined space. When the air inside the cylinder is heated it will expand and when cooled it contract. All 4 image are borrowed from there respected sites. as the images are very informative so I included it here. I would like also to mention approtechie for his Stirling engine which inspires me to create my own. Some of measurement are almost identical to his engine including the use of stainless bottle as cylinder.

In order for you to build a running engine might as well read this pdf from Andy Ross a prominent Stirling Engine experimenter. It help me a lot page 9. If your engine doesn't work for the first time don't worry because I made 5 different engine using different materials from trash to barely running to wow!.

Step 2: Preparing Materials and Tools

Prepare the materials and tools necessary for the project. This part was second most laborious to my part because I started my project without a guide or manual. It was like an building a puzzle and its pieces are not included in the set.

stainless water bottle

steel wool pack #00

luncheon meat can

wooden chopping board

dip cloth hanger

aluminum can

defective hard disk drive

terminal blocks

RTV silicone

steel filled epoxy

steel or copper or aluminum tube


Step 3: Building the Engine (cylinder)

The engine cylinder will house the displacer and the piston.

Cut the stainless bottle near its neck, I done it by using sharp pointed knife and hitting the knife with a hammer to puncture the bottle. be careful in doing it the knife usually bounce when hit by hammer. If you have a better way of cutting it do it. I only done it because its the only tools I have.

After I poorly cut it, I put a masking take around the bottle as the picture shown and it will serve as a marking and making sure that the bottle height is 15cm.Then I cut it using tinsnip to remove jagged edge of the bottle by carefully following the marking.

Step 4: Building the Engine (displacer)

The displacer purpose is to move the air from cold side to hot side of the cylinder. While it displaces the air it also regenerator or economizer as what Robert Stirling call it. The regenerator removes the heat from air as the air moves from hot side to called side. When the air moves from cold side to warm the heat from the regenerator are transfered back to the air.

The steel wool is used as the displacer so it will act as regenerator at the same time.

As i rolled the steel wool I sandwich an aluminum foil from disposable aluminum pan to add firmness to its shape.

The foil is not visible since it was wrapped up by wool.

The height of the displacer is 10cm its diameter is almost the same as the cylinder not too tight not too loose.

The displacer must be 2/3 the height of cylinder.

Step 5: Building the Engine (crankshaft)

One of important consideration in crankshaft is balance, placing of connecting rod, and reduction of friction.

my crankshaft is not well balance but its good enough.

Piston throw is 3cm or 1.5cm radius.

Displacer throw is 5cm or 2.5 radius.

The piston and displacer must be 90 degree apart.

Step 6: Building the Engine (coolant Cover and Piston Base)

Step 7: Building the Engine (power Piston)

The Power piston I used here is a RTV silicone using illustration board as mold.

Using alternate diameter of board as a mold.

The diameter of the mold is exactly the diameter of the cylinder.

the base of the piston is wider by 1 cm so it can be attached in the wooden cover.

Step 8: Building the Engine (connecting Rod)

the connecting rods are made from wire hanger. connected to crankshaft using terminal block. sorry no picture as of this time. i'll add it later.

Step 9: Building the Engine (coolant)

The engine coolant will serve as the cold side of the engine. The better the cooling of this part will give better contraction of air thus better piston drive.

The can is opened in the bottom just enough for snug fit of cylinder.

The wood pieces are attached in the can using 2 small wood screw in both side.

I used red RTV silicone as sealant to prevent water leak.

the chopping board serves a cover.

I attached to stainless tube 5mm in diameter about 5cm long. It will serves as water intake and water outlet.

The longer one 8cm long serves as intake and the shorter one serves as outlet of warmer water.

Step 10: Attaching Generator

The generator I use in this project came from mini fan . The winding are 500 turns of #21 AWG enamel wire.

You can use any small DC motor. Just observe polarity. Polarity depends upon the direction of rotation. Just experiment with it.

If you have this kind of mini fan and decided to use it this becomes an AC generator you will be needing a full bridge rectifier to convert AC to DC

Step 11: Solar Tracker

Step 12: Flat Fresnel Solar Reflector

Step 13: Some of the First Built

Some run a little other barely rotate and there are more that I just put in trash. aluminum can work but it cant handle too much heat.


PhilippeG1 (author)2016-10-30

Made in africa

Vous pouvez prendre 2 moteurs de voiture diesel 4 cylindres en ligne type super-carré (1 dédié à la zone chaude et l'autre dans la zone froide) du côté de montage côte à côte, et connecter le vilebrequin par une chaîne ou la courroie de distribution avec une phase changement d'un quart de tour entre les deux vilebrequins. Les deux moteurs sont utilisés pour obtenir un minimum de Stirling moteur 60 kW (ou 100 kilowatts!). Il est nécessaire de connecter chaque cylindre pour refroidir son chaud par une reprise correspondante en se branchant sur les ouvertures d'échappement. Pour travailler avec des pressions élevées, utiliser les tuyaux de plomberie en cuivre. les soupapes et l'arbre à cames sont utilisés dans tout et donc éliminés ainsi que la partie arrière de la boîte de vitesses et que l'entrée d'huile de l'arbre à cames doit être fermé. Les injecteurs sont utilisés pour mettre le cylindre sous pression d'air. se connecter à un compresseur. La connexion entre le vilebrequin et les bielles peut être réalisé avec des roulements à rouleaux. Il est même possible de récupérer les anneaux de cuivre et de les usiner pour devenir des cages de roulements à rouleaux Puisque nous travaillons en "basse température" Vous pouvez modifier les segments de métal par des segments de polymères appropriés pour réduire la friction. Il suffit d'envoyer l'eau ou mieux l'huile chaude dans le circuit d'eau chaude du bloc moteur et de l'eau ou de l'huile froide dans le circuit d'eau du bloc moteur froid pour faire fonctionner le moteur Stirling. Dans ce cas, nous pouvons utiliser un radiateur de voiture avec la pompe à eau du moteur pour capter la chaleur de la source de chaleur (rayonnement solaire, la combustion des déchets, etc etc) permettant d'expulser l'absorption de la chaleur du moteur Stirling (fournir tous les mêmes thermique isolation des tuyaux). Enfin, si nous intercalons un grand réservoir d'huile pour absorber l'excès de chaleur pendant la journée, nous pouvons accumuler suffisamment de calories pour faire fonctionner le moteur toute la nuit, et ont le pouvoir 24/24.

SkylarG4 (author)PhilippeG12017-05-08

Hi I had seen this article.

Is there a full instruction manual and has anyone done this yet??

I want to build one. and would like to know how much time and investment is will be

RahimD (author)2016-10-09

Hey can you how much voltage this provides.What is the power produced.I want to run some medical appliances via sterling engine.Please reach out to me on or

jparacuelles (author)RahimD2016-10-30

My stirling engine needs further development... If you want to run a medical appliance it would be wise to go solar.

RajeshS16 (author)2015-07-26

BoyluckyM (author)2015-03-24

Hi, this is really great project. I hope that one day I will also make one Stirling.

By the way when you speak about power generation have you ever thing about to make something similar to stirling but which would only make lets say some vibration instead of movement of the circle? I mean what would you think about to make a machine which would transfer heat to vibration only which would generate power.

And keep going with your project, that realy looks great.

jparacuelles (author)BoyluckyM2015-03-24

yeah it could be a great way to convert energy but i think I cant produce enough power by using the vibration alone. I also found out that linear generator also works.

BoyluckyM (author)jparacuelles2015-03-26

Hi jparacuelles, I think there could be a way. What about to do it on same base as the speaker is working. But whould you have an idea how to convert heat to vibration?

I have one more idea. I was thinking how to make a stirling as simple as possible but powerfull enough to generate an electricity. Then I end up with idea to only keep a piston closed from both sides. Inside there would be a moving part in which could be positioned also permanent magnet. Then if the heat is brought to one side of the piston the middle part will move. Then there would be heat brought to oposite side of piston and movement would be done in other direction. The idea is to use a sunbeam as the heater because it can by quite simple to direct it first on one side of the piston and then to another side. What would you think about it?

BoyluckyM (author)BoyluckyM2015-03-29

I see that what I described looks like the linear generator which you mentioned before :o) so I meant something like that.

Plognark (author)2015-03-19

Very cool project, this is something I've been wanting to work on too. Converting heat directly into mechanical motion was such a novel discovery for me that I've been kind of obsessed with these for years.

Any concerns with friction from the regenerator robbing power? I know it's not much, but every little bit helps. It seems like the steel wool might rub on the sides if it's not well contained.

jparacuelles (author)Plognark2015-03-24

you need to add small clearance so it wont rub. anyway steel wool is so soft that it will be deformed if rub against the side of cylinder.

tomatoskins (author)2015-03-02

This looks great! Over the last few weeks I've grown a love for the stirling engine.

jparacuelles (author)tomatoskins2015-03-02

I feel the same,that's why even if my first engines didn't run I never stop making it.

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