How to make a Stirling engine at home? Power plants using a Stirling engine - simplicity, efficiency and environmental safety Do-it-yourself external combustion Stirling engine.

A Stirling engine is an engine that can be powered by thermal energy. In this case, the heat source is absolutely not important. The main thing is that there is a temperature difference, in which case this engine will work. The author figured out how to make a model of such an engine from a Coca-Cola can.

At the final stage, the lid must be cut as shown in the picture. This is done so that the displacer wire does not catch on the edges of the cover. Household scissors are suitable for such work.

As a result, on one side of the cotton wool you need to form a spiral of wire so that it does not come out of the cotton wool, and on the other side a loop is made from wire. Next, a fishing line is tied to this loop, which is subsequently pulled through the center of the diaphragm. The vulcanized rubber should be in the middle of the container.

At the final stage, the entire mechanism is assembled together.

Ecology of consumption. Science and technology: The Stirling motor is most often used in situations where a device for converting thermal energy is required that is simple and efficient.

Less than a hundred years ago, internal combustion engines tried to gain their rightful place in the competition among other available machines and moving mechanisms. Moreover, in those days superiority gasoline engine was not so obvious. Existing machines powered by steam engines were distinguished by their quietness, excellent power characteristics for that time, ease of maintenance, and the ability to use various types fuel. In the further struggle for the market, internal combustion engines, due to their efficiency, reliability and simplicity, gained the upper hand.

The further race to improve units and driving mechanisms, which gas turbines and rotary types of engines entered in the mid-20th century, led to the fact that, despite the supremacy of the gasoline engine, attempts were made to introduce completely the new kind engines - thermal, first invented back in 1861 by a Scottish priest named Robert Stirling. The engine received the name of its creator.

STIRLING ENGINE: PHYSICAL SIDE OF THE ISSUE

To understand how a tabletop Stirling power station works, you need to understand general information on the principles of operation of heat engines. Physically, the principle of operation is to use mechanical energy, which is obtained when gas expands when heated and its subsequent compression when cooled. To demonstrate the principle of operation, we can give an example based on an ordinary plastic bottle and two pans, one of which contains cold water, the other hot.

When lowering the bottle into cold water, the temperature of which is close to the temperature of ice formation, when the air inside the plastic container is sufficiently cooled, it should be closed with a stopper. Further, when the bottle is placed in boiling water, after some time the cork “shoots” with force, since in this case the work done by the heated air was many times greater than that done during cooling. If the experiment is repeated many times, the result does not change.

The first machines that were built using the Stirling engine accurately reproduced the process demonstrated in experiment. Naturally, the mechanism required improvement, which consisted in using part of the heat that the gas lost during the cooling process for further heating, allowing the heat to be returned to the gas to accelerate heating.

But even the use of this innovation could not save the situation, since the first Stirlings were different large sizes at low power output. Subsequently, attempts were made more than once to modernize the design to achieve a power of 250 hp. led to the fact that in the presence of a cylinder with a diameter of 4.2 meters, the actual power output produced by the Stirling power station of 183 kW was in fact only 73 kW.

All Stirling engines operate on the principle of the Stirling cycle, which includes four main phases and two intermediate ones. The main ones are heating, expansion, cooling and compression. The transition stage is considered to be the transition to the cold generator and the transition to the heating element. Useful work performed by the engine is based solely on the temperature difference between the heating and cooling parts.

MODERN STIRLING CONFIGURATIONS

Modern engineering distinguishes three main types of such engines:

• alpha-stirling, the difference of which is two active pistons located in independent cylinders. Of all three options, this model differs the most high power, having the highest temperature of the heating piston;
• beta stirling, based on one cylinder, one part of which is hot and the other cold;
• Gamma Stirling, which in addition to the piston also has a displacer.

The production of the Stirling power station will depend on the choice of engine model, which will take into account all the positive and negative sides similar project.

ADVANTAGES AND DISADVANTAGES

Thanks to your design features These engines have a number of advantages, but are not without disadvantages.

Tabletop Stirling power station, which cannot be purchased in a store, but only from hobbyists who independently assemble such devices, include:

• large sizes, which are caused by the need for constant cooling of the working piston;
• usage high pressure what is required to improve engine performance and power;
• heat loss, which occurs due to the fact that the generated heat is transferred not to the working fluid itself, but through a system of heat exchangers, whose heating leads to a loss of efficiency;
• a sharp reduction in power requires the use of special principles that differ from those traditional for gasoline engines.

Along with the disadvantages, power plants operating on Stirling units have undeniable advantages:

• any type of fuel, since like any engines that use thermal energy, this engine is capable of operating at a temperature difference of any environment;
• efficiency. These devices can be an excellent replacement for steam units in cases where it is necessary to process solar energy, providing an efficiency of 30% higher;
• environmental Safety. Since the tabletop kW power station does not create exhaust torque, it does not produce noise or emit emissions into the atmosphere. harmful substances. Ordinary heat acts as a source of power, and the fuel burns out almost completely;
• structural simplicity. For its work, Stirling will not require additional details or devices. It is capable of starting independently without using a starter;
• increased performance resource. Due to its simplicity, the engine can provide hundreds of hours of continuous operation.

AREAS OF APPLICATION OF STIRLING ENGINES

The Stirling motor is most often used in situations where a simple device for converting thermal energy is required, while the efficiency of other types of thermal units is significantly lower under similar conditions. Very often such units are used in food pumping equipment, refrigeration chambers, submarines, energy storage batteries.

One of promising directions areas of use of Stirling engines are solar power plants, since this unit can be successfully used to convert the energy of solar rays into electricity. To carry out this process, the engine is placed at the focal point of a mirror that accumulates solar rays, which provides permanent illumination of the area requiring heating. This allows solar energy to be focused on a small area. The fuel for the engine in this case is helium or hydrogen. published

In which the working fluid (gaseous or liquid) moves in a closed volume, it is essentially a type of external combustion engine. This mechanism is based on the principle of periodic heating and cooling of the working fluid. Energy is extracted from the emerging volume of the working fluid. The Stirling engine operates not only from the energy of burning fuel, but also from almost any source. This mechanism was patented by the Scotsman Robert Stirling in 1816.

The described mechanism, despite its low efficiency, has a number of advantages, first of all, it is simplicity and unpretentiousness. Thanks to this, many amateur designers attempt to assemble a Stirling engine with their own hands. Some succeed and some don't.

In this article we will look at DIY Stirling from scrap materials. We will need the following blanks and tools: a tin can (can be from sprats), sheet metal, paper clips, foam rubber, rubber band, bag, wire cutters, pliers, scissors, soldering iron,

Now let's start assembling. Here detailed instructions to how to make a Stirling engine with your own hands. First you need to wash the jar, clean sandpaper the edges. We cut a circle out of sheet metal so that it fits on the inner edges of the can. We determine the center (for this we use a caliper or ruler), make a hole with scissors. Next we take copper wire and a paper clip, straighten the paper clip and make a ring at the end. We wind the wire around the paperclip - four tight turns. Next, use a soldering iron to tin the resulting spiral with a small amount of solder. Then you need to carefully solder the spiral to the hole in the lid so that the rod is perpendicular to the lid. The paperclip should move freely.

After this, you need to make a connecting hole in the lid. We make a displacer from foam rubber. Its diameter should be slightly smaller than the diameter of the can, but there should not be a large gap. The height of the displacer is a little more than half the can. We cut a hole in the center of the foam rubber for the sleeve; the latter can be made of rubber or cork. We insert the rod into the resulting bushing and seal everything. The displacer must be placed parallel to the lid, this important condition. Next, all that remains is to close the jar and seal the edges. The seam must be sealed. Now we begin to manufacture the working cylinder. To do this, cut out a strip of tin 60 mm long and 25 mm wide, bend the edge 2 mm with pliers. We form a sleeve, then solder the edge, then you need to solder the sleeve to the lid (above the hole).

Now you can start making the membrane. To do this, cut a piece of film from the bag, press it inward a little with your finger, and press the edges with an elastic band. Next you need to check the correct assembly. Heat the bottom of the jar over the fire and pull the stem. As a result, the membrane should bend outward, and if the rod is released, the displacer under own weight should fall, accordingly, the membrane returns to its place. If the displacer is not made correctly or the soldering of the can is not airtight, the rod will not return to place. After this we make the crankshaft and struts (the crank spacing should be 90 degrees). The height of the cranks should be 7 mm, and the height of the displacers 5 mm. The length of the connecting rods is determined by the position of the crankshaft. The end of the crank is inserted into the plug. So we looked at how to assemble a Stirling engine with our own hands.

Such a mechanism will work from a regular candle. If you attach magnets to the flywheel and take the coil of an aquarium compressor, then such a device can replace a simple electric motor. As you can see, making such a device with your own hands is not at all difficult. There would be a desire.

Stirling's engine. For almost any homemade person, this wonderful thing can become a real drug. It’s enough to do it once and see it in action, and you’ll want to do it again and again. The relative simplicity of these engines allows them to be made literally from garbage. I won't stop there general principles and device. There is a lot of information about this on the Internet. For example: Wikipedia. Let's proceed immediately to the construction of the simplest low-temperature gamma-Stirling.

To build an engine with our own hands, we will need two covers for glass jars. They will serve as the cold and hot parts. The edge of these lids is cut off with scissors.

A hole is made in the center of one lid. The size of the hole should be slightly smaller than the diameter of the future cylinder.

The Stirling engine housing is cut from plastic bottle from under the milk. These bottles are just divided into rings. We'll need one. It should be noted that bottles may differ slightly for different types of milk.

The body is glued to the lid with plastic epoxy or sealant.

The marker body is perfect as a cylinder. This model has a cap that is smaller in diameter than the marker itself and can become a piston.

A small part is cut off from the marker. A part from the top of the cap is cut off.

This is a displacer. When a Stirling engine operates, it moves air inside the housing from the hot part to the cold part and back again. Made from dishwashing sponge. A magnet is glued in the center.

Since the top cover is made of tin, it can be attracted by a magnet. The displacer may become stuck. To prevent this from happening, the magnet must be additionally secured with a cardboard circle.

The cap is filled with epoxy compound. Holes are drilled at both ends for attaching the magnet and connecting rod holder. The threads in the holes are cut directly with a screw. These screws are needed for fine tuning engine. A magnet in the piston is glued to the screw and adjusted so that, being at the bottom of the cylinder, it attracts the displacer. You will also need to glue a rubber stopper onto this magnet. A piece of bicycle tube or an eraser will do. The limiter is needed to prevent the magnets of the piston and displacer from being attracted too strongly. Otherwise, the pressure may not be enough to break the magnetic connection.

On top part A rubber gasket is glued onto the piston. It is needed for tightness and to protect the casing from rupture.

The piston housing is made of a rubber glove. You need to cut off your little finger.

After the casing is glued, another rubber gasket is glued on top. Through rubber gaskets and a hole is pierced into the casing with an awl. The connecting rod holder is screwed into this hole. This holder is made from a screw and a soldered washer.

Epoxy packaging worked perfectly as a crankshaft holder. The exact same jar can be taken from effervescent vitamins or aspirin.

The bottom of this jar is cut off and holes are made. In the upper part - to hold the crankshaft. At the bottom - for access to the connecting rod mount.

The crankshaft and connecting rod are made of wire. The white things are the limiter. Made from a Chupa Chups tube. Small pieces are cut from this tube and the resulting parts are cut lengthwise. This makes them easier to put on. The height of the elbow is determined by half the distance that the cylinder must travel from the lowest point to the highest point at which the magnetic connection ceases to operate.

So, we are all ready for the first tests. First you need to check the tightness. You need to blow into the cylinder. You can apply foam from dishwashing liquid to all joints. The slightest air leak and the engine will not work. If everything is OK with the seal, you can insert the piston and secure the casing with a rubber band.

In the lower position of the cylinder, the displacer should be pulled to the top. Next, the entire structure is placed on a cup with hot water. After some time, the air inside the engine will begin to heat up and push the piston out. At a certain moment, the magnetic connection will be broken and the displacer will fall to the bottom. This way, the air in the engine will stop contacting the heated part and will begin to cool. The piston will begin to retract. Ideally, the piston should begin to move up and down. But this may not happen. Either the pressure will not be enough to move the piston, or the air will heat up too much and the piston will not retract all the way. Accordingly, this engine may have dead zones. It's not particularly scary. The main thing is that the dead zones are not too large. To compensate for dead spots, a flywheel is needed.

Another very important part of this stage is that here you can feel the principle of operation of the Stirling engine. I remember my first stirling which didn’t work only because I couldn’t figure out how and why this thing works. Here, by helping the piston move up and down with your hands, you can feel how the pressure rises and falls.

This design can be slightly improved by adding a syringe to the top cap. This syringe also needs to be mounted on epoxy, the needle holder must be trimmed a little. The piston position in the syringe should be in the middle position. This syringe can be used to regulate the air volume inside the engine. Starting and adjusting will be much easier.

So you can install the crankshaft holder. The height of attachment of the connecting rod to the cylinder is adjusted with a screw.

The flywheel is made from a CD. The hole is sealed with plastic epoxy. Then you need to drill a hole exactly in the center. Finding the center is very easy. Using properties right triangle inscribed in a circle. Its hypotenuse passes through the center. You need to attach a sheet of paper at a right angle to the edge of the disk. Orientation doesn't matter. Place marks where the sides of the sheet intersect with the edge of the disk. A line drawn through these marks will pass through the center. If we draw a second line in a different place, then at the intersection we will get the exact center.

The engine is ready.

Place the Stirling engine on a cup of boiling water. We wait a little and it should work on its own. If this does not happen, you need to help him slightly with your hand.

The manufacturing process on video.

Stirling engine at work

You can, of course, buy beautiful factory models of Stirling engines, such as in this Chinese online store. However, sometimes you want to create yourself and make a thing, even from improvised means. On our website there are already several options for manufacturing these motors, and in this publication, check out the complete simple option made at home.

To make it, you will need available materials: a can of canned food, a small piece of foam rubber, a CD, two bolts and paper clips.

Foam rubber is one of the most common materials used in the manufacture of Stirling motors. The engine displacer is made from it. We cut out a circle from a piece of our foam rubber, make its diameter two millimeters less than the inner diameter of the can, and its height a little more than half of it.

We drill a hole in the center of the cover into which we will then insert the connecting rod. For smooth running of the connecting rod, we make a spiral from a paper clip and solder it to the lid.

We pierce the foam circle of foam rubber in the middle with a screw and secure it with a washer at the top and at the bottom with a washer and nut. After this, we attach a piece of paper clip by soldering, having first straightened it.

Now we stick the displacer into the hole made in advance in the lid and hermetically solder the lid and the jar together. We make a small loop at the end of the paperclip, and drill another hole in the lid, but a little larger than the first.

We make a cylinder from tin using soldering.

We attach the finished cylinder to the can using a soldering iron, so that there are no gaps left at the soldering site.

We make a crankshaft from a paper clip. The knee spacing should be 90 degrees. The knee that will be above the cylinder in height is 1-2 mm larger than the other.

We use paper clips to make stands for the shaft. We make a membrane. To do this, we put on the cylinder plastic film, push it inward a little and secure it to the cylinder with thread.

We make the connecting rod that will need to be attached to the membrane from a paper clip and insert it into a piece of rubber. The length of the connecting rod must be made such that at the bottom dead center of the shaft the membrane is pulled inside the cylinder, and at the highest, on the contrary, it is extended. We set up the second connecting rod in the same way.

We glue the connecting rod with rubber to the membrane, and attach the other one to the displacer.

We use a soldering iron to attach the paper clip legs to the can and attach the flywheel to the crank. For example, you can use an CD.

Stirling engine made at home. Now all that remains is to bring heat under the jar - light a candle. And after a few seconds give a push to the flywheel.

How to Make a Simple Stirling Engine (with Photos and Video)

www.newphysicist.com

Let's make a Stirling engine.

A Stirling engine is a heat engine that operates by cyclically compressing and expanding air or other gas (working fluid) at various temperatures so that there is a net conversion of thermal energy into mechanical work. More specifically, the Stirling engine is a closed-cycle regenerative thermal engine with a continuously gaseous working fluid.

Stirling engines have higher efficiency than steam engines and can reach 50% efficiency. They are also capable of operating silently and can use almost any heat source. The thermal energy source is generated externally to the Stirling engine rather than through internal combustion as is the case with Otto cycle or diesel cycle engines.

Stirling engines are compatible with alternative and renewable energy sources, because they may become increasingly significant as the price of traditional fuels rises and in light of problems such as depletion of oil reserves and changing of the climate.

In this project we will give you simple instructions to create a very simple engine DIY Stirling using a test tube and syringe .

How to make a simple Stirling engine – Video

Components and Steps to Make a Stirling Motor

1. A piece of hardwood or plywood

This is the basis for your engine. Thus, it must be rigid enough to cope with the movements of the engine. Then make three small holes as shown in the picture. You can also use plywood, wood, etc.

2. Marble or glass balls

In the Stirling engine these balls perform important function. In this project, the marble acts as a displacer of hot air from the warm side of the test tube to the cold side. When marble displaces hot air, it cools.

3. Sticks and screws

Pins and screws are used to hold the test tube in a comfortable position for free movement in any direction without any interruption.

4. Rubber pieces

Buy an eraser and cut it into the following shapes. It is used to hold the test tube securely and maintain its seal. There should be no leakage at the mouth of the tube. If this is the case, the project will not be successful.

5. Syringe

The syringe is one of the most important and moving parts in simple engine Stirling. Add some lubricant inside the syringe so that the plunger can move freely inside the barrel. As air expands inside the test tube, it pushes the piston down. As a result, the syringe barrel moves upward. At the same time, the marble rolls towards the hot side of the test tube and displaces the hot air and causes it to cool (reduce volume).

6. Test Tube The test tube is the most important and working component of a simple Stirling engine. The test tube is made of a certain type of glass (such as borosilicate glass) that is highly heat resistant. So it can be heated to high temperatures.

How does a Stirling engine work?

Some people say that Stirling engines are simple. If this is true, then just like the great equations of physics (e.g. E = mc2), they are simple: simple on the surface, but richer, more complex, and potentially very confusing until you realize them. I think it's safer to think of Stirling engines as complex: many very bad YouTube videos show how to easily "explain" them in a very incomplete and unsatisfactory way.

In my opinion, you can't understand a Stirling engine by simply building it or observing how it works from the outside: you need to think seriously about the cycle of steps it goes through, what happens to the gas inside, and how it differs from what what happens in a conventional steam engine.

All that is required for the engine to operate is a temperature difference between the hot and cold parts gas chamber. Models have been built that can only operate with a temperature difference of 4 °C, although factory engines will likely operate with a difference of several hundred degrees. These engines may become the most efficient form of internal combustion engine.

Stirling engines and concentrated solar power

Stirling engines provide a neat method of converting thermal energy into motion that can drive a generator. The most common design is to have the motor at the center of a parabolic mirror. A mirror will be mounted on the tracking device so that the sun's rays are focused on the engine.

* Stirling engine as receiver

You may have played with convex lenses during your school days. Concentration solar energy for burning a piece of paper or a match, am I right? New technologies are developing day by day. Concentrated solar thermal energy is gaining more and more attention these days.

Above is a short video of a simple test tube motor using glass beads as the displacer and a glass syringe as the force piston.

This simple Stirling engine was built from materials that are available in most school science laboratories and can be used to demonstrate a simple heat engine.

Pressure-volume diagram per cycle

Process 1 → 2 Expansion of the working gas at the hot end of the test tube, heat is transferred to the gas, and the gas expands, increasing the volume and pushing the syringe plunger upward.

Process 2 → 3 As the marble moves towards the hot end of the test tube, gas is forced from the hot end of the test tube to the cold end, and as the gas moves, it transfers heat to the wall of the test tube.

Process 3 → 4 Heat is removed from the working gas and the volume decreases, the syringe piston moves down.

Process 4 → 1 Completes the cycle. The working gas moves from the cold end of the test tube to the hot end as the marbles displace it, receiving heat from the wall of the test tube as it moves, thereby increasing the pressure of the gas.