Parabolic mirror. Or we cook soup without fire. Construction of an amateur telescope from Chinese components Silver plating using chemistry

15.06.2019

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The starry sky has always attracted researchers; probably everyone at least once in their life dreamed of discovering some star or constellation and naming it in honor of a person close to them. I present to your attention a small guide, which consists of two parts, which provide a detailed description of how do from scratch their hands wooden telescope. This part will show you how you can make key element telescope: primary mirror.

A good mirror will help you see various details of the Moon and planets solar system and other objects deep space while a poor quality mirror will give you only blurry outlines of objects.

Telescope mirrors require an extremely precise surface. In most cases, excellent quality mirrors are achieved by hand polishing rather than machine polishing. This is one of the reasons why some people prefer to make their own mirrors rather than buy cheap ones. industrial designs. The second reason is that you will acquire the necessary knowledge to produce high-quality optical instruments, and as you know, you can’t carry knowledge behind your shoulders.

Step 1: Materials

The blank glass is made of a material with a low coefficient of expansion (Pyrex, borosilicate glass, Duran 50, Cerodur, etc.);
Silicon carbide of various grain sizes (60, 80, 120, 220, 320 units);
Aluminum oxide (25, 15, 9 and 5 microns);
Cerium oxide;
Resin;
Grindstone;
Waterproof plaster (dental plaster);
Ceramic tile;
Epoxy adhesive.

Step 2: Preparing the workpiece

Glass blanks often come with marks on the surface. The “round mark” in the lower part was left by the stove, and the upper marks appeared as a result of the temperature difference when the glass cooled.

Let's start by treating the edges of the glass to limit the risk of chipping. A whetstone is an excellent tool for this operation. Don't forget about the funds personal protection respiratory organs and remember that glass and stone should be moistened with water (as glass dust is very bad for the lungs).

The bottom of the mirror should be as flat as possible (before you start working on it). To level the surface we will use coarse carborundum (silicon carbide #60). Spread the powder and water on a flat surface and rub the glass over it. After a few seconds, you will see a gray paste. Rinse it off and add wet sand. Continue until the surface is clear of holes and potholes.

Step 3:

This jig will be used to create a concave surface on a glass piece.

Let's cover the glass plastic film. Let's make a cardboard cylinder around the workpiece and pour plaster inside. Let it dry, then remove the cardboard. Carefully peel away the glass and remove burrs from the edges.

Step 4: Ceramic Tile Covering

We need a hard surface to polish the glass. That is why the convex part of the workpiece must be covered with ceramic tiles.

Glue the tiles onto gypsum base epoxy resin.

Please note that placing tiles or holes in the center should be avoided. Instead, offset the tile slightly to avoid any central imperfection on the mirror surface.

Step 5: Start Sanding

Let's put some wet sand on the surface of the tile and start rubbing the glass on it.

After several passes, turn the mirror and continue sanding in the other direction. This provides good processing, from all angles and will prevent mistakes.

Step 6:

We continue sanding until we get the desired bend. To estimate curvature, you must use the calculator from the Sagitta measurement set.

If you want to build a telescope for observing planets, you will need a larger focal ratio (F/8 or higher).

On the other hand, if you want to contemplate the expanse of the galaxy and stellar nebulae, you will need a small focal ratio (F/4, for example).

Focal ratio F/4.75. The sagitta of my 20 cm mirror is 0.254 cm.

Step 7: Smooth the Surface

Once the required curvature is achieved, you need to smooth the surface while maintaining the same curvature.

Mark large flaws with a marker and continue sanding until they are completely removed. This will provide visual confirmation that you can switch to a finer abrasive.

Let's move on to #320 silicon carbide. Once you have reached this step, you should start to see some reflections when peering into the mirror blank.

Step 8:

We need to make another tool for this operation. You can make such a device from plaster or thick plywood. She will be covered soft material- resin.

Resin coniferous trees– very sticky and difficult to clean off.

Make another cylinder around the base of the jig. Melt a large amount of resin and pour it into the cylinder. Let the resin cool and remove the cardboard casing. After this, we will begin to form the surface; it is necessary to give it a slight convexity. The created channels will also help you when processing glass.

Step 9: Polish

Place some wet cerium powder on the resin and start rubbing the mirror against it. Cerium will penetrate the surface of the resin. Use soapy lubricant if necessary.

Step 10: Making a Foucault tester

Foucault tester is a tool designed to analyze the surface of parabolic mirrors. It has a light source that shines onto the mirror. When the light returns, it is focused in a different area (if it came from the edge or center of the mirror).

The tester uses this principle to allow you to visually see errors in the range of 1 millionth of a cm. By adding a Ronchi screen to the tester you will save time because you will get an idea of the surface without any measurements.

To make life easier, make a mirror stand. A screw at the back allows you to adjust the angle.

Step 11: Making a paraboloid

After the finishing stage, we should have a fully polished mirror with a beautiful spherical surface. However, the sphere is not suitable for astronomical purposes. We must get a paraboloid.

The difference between a sphere and a paraboloid is small (about 1 micron). To achieve this difference we will use a Foucault test. Since we know what the reflection should look like, we will do special finishing with cerium oxide until the reflection on the mirror matches the theoretical one.

The appearance of the grind will resemble a "W". The amplitude should be 4/5 of the diameter in the transverse and longitudinal direction.

There is also full list various techniques to correct errors on a specific surface.

Step 12: Surface Testing Using a Foucault Tester

This is what the reflection looks like in a Foucault tester equipped with a Ronchi grid.

Depending on the case (the mesh cuts the light before or after the radius of curvature), the lines can be interpreted and the shape of the surface can be deduced.

The Couder mask is used for measurements with a Foucault tester.

Step 14: Aluminizing

In order to completely complete the craft, it needs to be sent for aluminization. Currently, the mirror reflects only 4% of the light. Aluminum contribution to the surface will increase the percentage by more than 90%.

An optional addition - a SiO2 coating will help protect the metal from any source of oxidation.

You can add a center imprint - this helps with collimation and does not affect the quality of the mirror, since the center does not participate in the formation of the image that you will see in the eyepiece.

To be continued…

I have always wanted to have a telescope to observe the starry sky. Below is a translated article by an author from Brazil who was able to make a mirror telescope with his own hands and from available materials. Saving a lot of money at the same time.

Everyone loves to look at the stars and look at the moon in the clear night. But sometimes we want to see far. We want to see him nearby. Then humanity created a telescope!

Today
We have many types of telescopes, including the classical refractor and the Newtonian reflector. Here in Brazil, where I live, the telescope is a luxury. It costs between R$1,500.00 (about US$170.00) and R$7,500.00 (US$2,500.00). It's easy to find a refractor for R$500.00, but this is close 5/8 wages, considering that we have many poor families and young people waiting better life state. I'm one of them. Then I found a way to look at the sky! Why don't we make our own telescope?

Another problem here in Brazil is that we have very little content about telescopes.

Mirrors
and the lens is not particularly expensive. So, we do not have conditions for purchasing later. An easy way to do this is by using things that are no longer useful!

But where to find these things? Easily! The reflector telescope is made from:

— Primary mirror (concave)

— Secondary mirror (plan)

— Optical lens (the most difficult part!)

— Adjustable plug.

— Tripod;

Where can I find these things?
— Concave mirrors are used in beauty salons (makeup, shops, hairdresser, etc.);

— Flat mirrors are found in many things. You just need to find a small mirror (about 4 cm2);

— The optical lens is hardier to find. You can get it from a broken toy or make it yourself. (I used an old 10x lens from a broken pair of binoculars).

- Can be used water pipes(something between 80mm and 150mm in diameter) but I use an empty ink tin and a towel tin.

- Some black splashes.

You
You need PVC pipes, connectors and a few cardboard rolls too.

You can use hot glue or silicone paste.

So, no more waiting! Let's get it started!

Step 1: Calculation of optical components

I get 140mm Diameter of the concave mirror from Sagit from 3.18mm (measured with a caliper).

But first you should know that the mirror is Sagitta. In the depths of the mirror (the distance between the bottom surfaces and heights of boundaries).

Knowing this, we have:

Mirror radius (R) = d/2 = 70 mm

Radius of curvature (P) = P2 / 2C = 770.4 mm

Focal length (F) = p/2 = 385.2 mm

Aperture (F) = F / d = 2.8

Now we know everything we need to make our telescope!

Let's start!

Step 2: designing the main tube

By a strange coincidence, our paints are perfect for tin towels!

First we need to remove the paint on the bottom; we can’t.

Then you need to measure the distance between the concave mirror and the eyepiece location. To do this, you need to take into account the radius of the spray paint.

We then mark the height at 315mm. This is about 30 cm.

At this height, we make a hole in the can, as in the photo. IN in this case, I made a hole about 1.4 inches to fit the PVC connector.

As you can see in the next photo, the mirror fits perfectly into the can.

Step 3: Flat Mounting

I decided to fix it to support the mirror through 3 points, as in the drawing.

Fits the mirror plane, I used two wooden sticks and small wooden triangle from 45°.

Then I made some arrangements. With a drill, I made holes to insert the sticks.

Then I calculated the distance between the center of the mirror and the handle of the hole. This is 20 mm.

Make holes in the paint can with a drill.

So I adjusted the sticks to the plane of the mirror, when the eye holes are observed, my own eyes show.

*I attached the mirror in support with hot glue.

Step 4: Focus Adjustments

I used the microphone pedestal as a telescope tripod. Fitted with tape and elastic.

To find the hearth, we must aim for the sun with a telescope. Obviously, never look at the sun through a telescope!

Place the paper in front of the eye hole and find a smaller light spot. Then measure the distance between the hole and the paper as shown in the picture. Me from a distance of 6 cm.

This distance is required between the hole and the eyepiece. To fit the eyepiece I used a cardboard roll (from toilet paper), cut and fixed with a little tape.

Step 5: Support & Dress

Important detail:

Anything inside the pipe should be black. This prevents light from reflecting in other directions.

I drew ink on the outside of the black tin only on appearance. I also drove pins to hold the tin towels better in the tin paint.
Some other barretes hold better secondary mirror sticks... and then I fixed the "PVC tripod socket" with a rivet and hot glue.

I added a gold plastic edge to the top of the tin ink to make it look nice.

Step 6: Tests and Final Considerations

I waited for the dark like a child waits for a Christmas present. Then night came and I went outside to check my telescope. And here is the result:

As we know, it is very difficult to take photographs with a telescope.

For a very long time I wanted to make a solar parabolic concentrator. After reading a lot of literature on making a mold for a parabolic mirror, I settled on the simplest option - a satellite dish. The satellite dish has a parabolic shape that collects reflected rays at one point.

I looked at the Kharkov “Variant” plates as a basis. At a price that was acceptable to me, I could only purchase a 90 cm product. But the purpose of my experience is heat in focus. To achieve good results, you need a mirror area - the more, the better. Therefore, the plate should be 1.5 m, or better yet 2 m. The Kharkov manufacturer has these sizes in its assortment, but they are made of aluminum, and accordingly the prices are sky-high. I had to dive into the Internet in search of a used product. And in Odessa, builders, while dismantling some object, offered me a satellite dish measuring 1.36m x 1.2m, made of plastic. It was a little short of what I wanted, but the price was good and I ordered one plate.

Having received the plate a couple of days later, I discovered that it was made in the USA, had powerful stiffening ribs (I was worried whether the body was strong enough and whether it would move after gluing the mirrors on), and a strong orientation mechanism with many settings.

I also purchased mirrors, 3mm thick. Ordered 2 sq.m. - a little with reserve. Mirrors are sold mostly in 4 mm thickness, but I found a three to make it easier to cut. I decided to make the size of the mirrors for the concentrator 2 x 2 cm.

After collecting the main components, I began making a stand for the concentrator. There were several corners, pieces of pipes and profiles. I cut it to size, welded it, cleaned it and painted it. Here's what happened:

So, having made the stand, I started cutting the mirrors. The mirrors received dimensions of 500 x 500 mm. First of all, I cut it in half, and then with a 2 x 2 cm mesh. I tried a bunch of glass cutters, but now it’s not possible to find anything sensible in stores. A new glass cutter cuts perfectly 5-10 times, and that’s it... After that, you can immediately throw it away. Perhaps there are some professional ones, but you should not buy them in hardware stores. Therefore, if someone is going to make a concentrator from mirrors, the question of cutting the mirrors is the most difficult!

The mirrors are cut, the tripod is ready, I'm starting to glue the mirrors! The process is long and tedious. My number of mirrors on the finished hub was 2480 pieces. I chose the wrong glue. I bought a special glue for mirrors - it holds well, but it is thick. When sticking, squeezing a drop onto the mirror and then pressing it against the wall of the plate, there is a possibility of pressing the mirror unevenly (somewhere stronger, somewhere weaker). As a result, the mirror may not be glued tightly, i.e. will direct its ray of sun not to the focus, but near it. And if the focus is blurry - high results there's nothing to wait for. Looking ahead, I will say that my focus turned out to be blurry (from which I conclude that it was necessary to use a different glue). Although the results of the experiment were pleasing, the focus was approximately 10 cm in size, and around there was still a blurred spot of another 3-5 cm. The smaller the focus, the more accurate the focusing of the rays, the correspondingly higher the temperature. It took me almost 3 years to glue the mirrors full days. The area of the cut mirrors was about 1.5 sq.m. There was a marriage, at first, until he adapted - a lot, later significantly less. Defective mirrors probably amounted to no more than 5%.

The solar parabolic concentrator is ready.

When taking measurements, Maximum temperature at the focus of the concentrator was no less than 616.5 degrees. The sun's rays helped set a wooden board on fire, melting tin, a lead weight and an aluminum beer can. I conducted the experiment on August 25, 2015 in the Kharkov region, the village of Novaya Vodolaga.

The plans for next year (and maybe it will work out in winter period) adapt the concentrator to practical needs. Perhaps for heating water, perhaps for generating electricity.

In any case, nature gave us all most powerful source energy, you just need to learn how to use it. The energy of the sun covers all the needs of humanity thousands of times. And if a person can take at least a small part of this energy, then this will be the greatest achievement of our civilization, thanks to which we will save our planet.

Below is a video in which you will see the process of manufacturing a solar concentrator based on satellite dish, and the experiments that were done using the concentrator.

Startup company GoSol aims to make solar energy accessible to everyone on a global scale. To this end, it created an initiative to develop and disseminate instructions for assembling solar concentrators from local materials that could become effective sources heat for cooking, washing, water heating and heating.

“GoSol.org's mission is to eradicate energy poverty and minimize the effects of global warming by disseminating our DIY (Do It Yourself) technology and breaking down barriers to free access to solar energy. With your help, we want to encourage communities, entrepreneurs and craftsmen to harness the world's most powerful energy source. All materials and tools necessary to implement these technologies have already been produced and are present in abundance in all corners of the world,” says the GoSol website.

GoSol enthusiasts have launched a company with which they intend to raise $68,000 to make their goal a reality. The initiative has raised about $27,000 so far, and GoSol recently released its first instructions on how to build a solar concentrator.

Read also: Ripasso solar concentrator - the most effective method solar energy conversion?

Free step by step guide contains all the necessary information to create a 0.5 kW solar concentrator with your own hands. The reflective surface of the device will have an area of about 1 square meter, and the cost of its production will cost from $79 to $145, depending on the region of residence.

Sol1, the name given to the solar installation from GoSol, will take up approximately 1.5 cubic meters of space. The work on its production will take about a week. The materials for its construction will be iron corners, plastic boxes, steel rods, and the main working element - a reflective hemisphere - is proposed to be made from pieces of an ordinary bathroom mirror.

The solar concentrator can be used for baking, frying, heating water or preserving food through dehydration. The device can also serve as a demo efficient work solar energy and will help many entrepreneurs in developing countries start their own businesses. In addition to helping reduce harmful emissions into the atmosphere, GoSol solar concentrators will help reduce deforestation by replacing burned wood with clean energy from the sun.

The GoSol instructions can be used not only to create and practical application, but also for the sale of solar concentrators, which will help significantly reduce the threshold for access to solar energy, which today is mainly generated through photovoltaic solar panels. Their cost remains at an extremely high level in regions where it is often simply impossible to obtain energy by other means.

Free instructions for the solar concentrator are available on the GoSol website, and to receive it you will need to leave your email address to which updated information will be sent. If you want the “solar” initiative to move faster and on a larger scale, then you can support the company financially - the startup also accepts cash contributions, the reward for which will depend on the amount of the donation.

Read also: Ukrainian solar concentrator “Diversity” - instructions are freely available

Video: GoSol.org Free The Sun Campaign for Builders

ecotechnica.com.ua

Homemade solar concentrator made from mirror film

Great amount free energy people have been using sun, water and wind and much more that nature can provide for a long time. For some, this is a hobby, while others cannot survive without devices that can extract energy “out of thin air.” For example, in African countries, solar panels have long become a life-saving companion for people; solar-powered irrigation systems are being introduced in arid villages, solar pumps are being installed on wells, etc.

Solar ovens in this Chinese store.

In European countries the sun does not shine so brightly, but summer is quite hot, and it is a pity when the free energy of nature is wasted. There are successful designs of solar-powered ovens, but they use solid or prefabricated parabolic mirrors. Firstly, this is expensive, and secondly, it makes the structure heavier and therefore is not always convenient to use, for example, when a light weight of the finished concentrator is required. An interesting model of a homemade parabolic solar concentrator was created by a talented inventor. It does not require mirrors for its manufacture, so it is very light and will not be a heavy burden on a hike.

To create a homemade solar concentrator based on film, very few things are required. All of them are sold at any clothing market.1. Self-adhesive mirror film. It has a smooth, shiny surface and is therefore an excellent material for a mirror part. solar oven.2. A sheet of chipboard and a sheet of hardboard of the same size.3. Thin hose and sealant.

How to make a solar oven?

First, two rings are cut out from a chipboard of the size you need using a jigsaw, which must be glued to each other. There is one ring in the photo and video, but the author indicates that he later added a second ring. According to him, it would have been possible to limit ourselves to one, but the space had to be increased to form a sufficient concavity of the parabolic mirror. Otherwise the beam focus will be too far away. A circle of hardboard is cut to fit the size of the ring to form the back wall of the solar concentrator. The ring should be glued to the hardboard. Be sure to coat everything well with sealant. The structure must be completely sealed. Carefully make a small hole on the side so that there are even edges, into which tightly insert a thin hose. To ensure a tight seal, the connection between the hose and the ring can also be treated with sealant. Stretch a mirror film over the ring. Pump out the air from the installation body and thus form a spherical mirror. Bend the hose and clamp it with a clothespin. Do convenient stand for a finished concentrator. The energy of this installation is enough to melt an aluminum can.

Attention! Parabolic solar reflectors can be dangerous and can cause burns and eye damage if not handled carefully! Watch the video of the solar cooker making process.

Material used from the site zabatsay.ru. How to make a solar battery - here.

izobreteniya.net

How to make a solar concentrator with your own hands (for example, parabolic)

The problem of using solar energy has occupied the best minds of mankind since ancient times. It was clear that the Sun is a powerful source of free energy, but no one understood how to use this energy. If you believe the ancient writers Plutarch and Polybius, then the first person to practically use solar energy was Archimedes, who, with the help of certain optical devices he invented, managed to collect Sun rays into a powerful beam and burn the Roman fleet.

In essence, the device invented by the great Greek was the first solar radiation concentrator, which collected the sun's rays into one energy beam. And at the focus of this concentrator, the temperature could reach 300°C - 400°C, which is quite enough to ignite the wooden ships of the Roman fleet. One can only guess what kind of device Archimedes invented, although, according to modern ideas, he had only two options.

The very name of the device – solar concentrator – speaks for itself. This device receives the sun's rays and collects them into a single energy beam. The simplest concentrator is familiar to everyone from childhood. This is an ordinary biconvex lens, which could be used to burn out various figures, inscriptions, even entire pictures, when the sun's rays were collected by such a lens into a small point on wooden board, sheet of paper.

This lens belongs to the so-called refractory concentrators. In addition to convex lenses, this class of concentrators also includes Fresnel lenses and prisms. Long-focus concentrators built on the basis of linear Fresnel lenses, despite their cheapness, are used very little in practice, since they are large in size. Their use is justified where the dimensions of the concentrator are not critical.

Refractor Solar Concentrator

The prism solar radiation concentrator does not have this drawback. Moreover, such a device is also capable of concentrating part of the diffuse radiation, which significantly increases the power of the light beam. The triangular prism, on the basis of which such a concentrator is built, is both a radiation receiver and a source of an energy beam. In this case, the front face of the prism receives radiation, the back face reflects it, and radiation comes out of the side face. The operation of such a device is based on the principle of total internal reflection of rays before they hit the side face of the prism.

Unlike refractory concentrators, reflective concentrators operate on the principle of collecting reflected energy into an energy beam. sunlight. According to their design, they are divided into flat, parabolic and parabolic-cylindrical concentrators. If we talk about the effectiveness of each of these types, then the highest degree of concentration - up to 10,000 - is provided by parabolic concentrators. But to build systems solar heating Mostly flat or parabolic-cylindrical systems are used.

Parabolic (reflective) solar concentrators

Practical application of solar concentrators

Actually, the main task of any solar concentrator is to collect the sun's radiation into a single energy beam. And you can use this energy in various ways. You can heat water using free energy, and the amount of heated water will be determined by the size and design of the concentrator. Small parabolic devices can be used as a solar oven for cooking.

Parabolic concentrator as a solar oven

You can use them to provide additional lighting to solar panels to increase power output. And it can be used as an external heat source for Stirling engines. The parabolic concentrator provides a focal temperature of about 300°C – 400°C. If the focus is such a comparative small mirror If you place, for example, a stand for a kettle or a frying pan, you will get a solar oven on which you can very quickly cook food and boil water. A heater with a coolant placed at the focus will allow you to quickly heat even running water, which can then be used for household purposes, for example, for showering, washing dishes.

The simplest circuits heating water with a solar concentrator

If you place a Stirling engine of suitable power at the focus of a parabolic mirror, you can get a small thermal power plant. For example, Qnergy has developed and launched QB-3500 Stirling engines, which are designed to work with solar concentrators. In essence, it would be more correct to call them electric current generators based on Stirling engines. This unit produces electricity power 3500 watts. The output of the inverter is a standard voltage of 220 volts 50 hertz. This is quite enough to provide electricity to a house for a family of 4 people, or a summer cottage.

By the way, using the operating principle of Stirling engines, many craftsmen make devices with their own hands that use rotational or reciprocating motion. For example, water pumps for a summer residence.

The main disadvantage of a parabolic concentrator is that it must be constantly oriented towards the sun. Industrial helium installations use special tracking systems that rotate mirrors or refractors following the movement of the sun, thereby ensuring reception and concentration maximum quantity solar energy. For individual use, it is unlikely to be advisable to use such tracking devices, since their cost can significantly exceed the cost of a simple reflector on a regular tripod.

How to make your own solar concentrator

The easiest way to make a homemade solar concentrator is to use an old satellite dish. First you need to decide for what purposes this concentrator will be used, and then, based on this, choose the installation location and prepare the base and fastenings accordingly. Wash the antenna thoroughly, dry it, and stick a mirror film on the receiving side of the dish.

In order for the film to lay flat, without wrinkles or folds, it should be cut into strips no more than 3 to 5 centimeters wide. If you intend to use the concentrator as a solar oven, it is recommended to cut a hole with a diameter of approximately 5 - 7 centimeters in the center of the plate. A bracket with a stand for dishes (burner) will be passed through this hole. This will ensure that the container with the food you are preparing does not move when the reflector is turned towards the sun.

If the plate is small in diameter, then it is also recommended to cut the strips into pieces approximately 10 cm long. Glue each piece separately, carefully adjusting the joints. When the reflector is ready, it should be installed on a support. After this, you will need to determine the focus point, since the optical focus point at the satellite dish does not always coincide with the position of the receiving head.

Homemade solar concentrator - oven

To determine the focal point, you need to equip yourself with dark glasses, wooden plank and thick gloves. Then you need to point the mirror directly at the sun, catch a sunbeam on the board and, moving the board closer or further relative to the mirror, find the point where this bunny will have minimum dimensions- a small point. Gloves are needed to protect your hands from being burned if they accidentally fall into the area of the beam. Well, when the focal point is found, all that remains is to fix it and install the necessary equipment.

There are many options for making solar concentrators yourself. In the same way, you can make a Stirling engine yourself from scrap materials. And this engine can be used for a variety of purposes. How much imagination, desire and patience is enough?

solarb.ru

This DIY is about how to build solar water heater. It would be more correct to call it a parabolic solar concentrator. Its main advantage is that the mirror reflects 90% of solar energy, and its parabolic shape concentrates this energy at one point. This installation will work effectively in most regions of Russia, up to 65 degrees north latitude.

To assemble the collector, we need several basic things: the antenna itself, the sun tracking system and the heat exchanger-collector.

Parabolic antenna.

You can use any antenna - iron, plastic or fiberglass. The antenna should be a panel type, not a grid type. The antenna area and shape are important here. We must remember that heating power = antenna surface area. And that the power collected by an antenna with a diameter of 1.5 m will be 4 times less than the power collected by an antenna with a mirror area of 3 m.

You will also need a rotating mechanism for the antenna assembly. It can be ordered on Ebay or Aliexpress.

You will need a roll of aluminum foil or Mylar mirror film used for greenhouses. Glue that will stick the film to the parabola.

Copper tube with a diameter of 6 mm. Fittings for connecting hot water to a tank, to a pool, or wherever you will use this design. Swivel mechanism The author purchased tracking on EBAY for $30.

Step 1 Modify the antenna to focus solar radiation instead of radio waves.

You just need to attach the Mylar mirror film or aluminum foil to the antenna mirror.

You can order such a film on Aliexpress, if you suddenly don’t find it in stores.

It's almost as easy to do as it sounds. You just need to take into account that if the antenna, for example, has a diameter of 2.5 m and the film is 1 m wide, then there is no need to cover the antenna with film in two passes; folds and irregularities will form, which will worsen the focusing of solar energy. Cut it into small strips and attach it to the antenna with glue. Make sure the antenna is clean before applying the film. If there are places where the paint is swollen, clean them sandpaper. You need to smooth out all the unevenness. Please note that the LNB converter is removed from its place, otherwise it may melt. After sticking the film and installing the antenna in place, do not bring your hands or face close to the place where the head is attached; you risk getting serious sunburn.

Step 2 tracking system.

Parts list: geliotraker.zip (downloads: 371) * U1/U2 - LM339 * Q1 - TIP42C * Q2 - TIP41C * Q3 - 2N3906 * Q4 - 2N3904 * R1 - 1meg * R2 - 1k * R3 - 10k * R4 - 10k * R5 - 10k * R6 - 4.7k * R7 - 2.7k * C1 - 10n ceramics * M - DC motor up to 1A * LEDs - 5mm 563nm Video of the solar tracker working according to the scheme from the archive

You can make it yourself based on the front hub of a VAZ car.

For those interested, the photo was taken from here: Rotating mechanism

Step 3 Creating a heat exchanger-collector

To make a heat exchanger, you will need a copper tube, rolled into a ring and placed at the focus of our concentrator. But first we need to know the size of the dish's focal point. To do this, you need to remove the LNB converter from the plate, leaving the converter mounting posts. Now you need to turn the plate in the sun, having first secured a piece of board at the place where the converter is attached. Hold the board in this position for a while until smoke appears. This will take approximately 10-15 seconds. After this, turn the antenna away from the sun and remove the board from the mount. All manipulations with the antenna, its reversals, are carried out so that you do not accidentally put your hand into the focus of the mirror - this is dangerous, you can get seriously burned. Let it cool down. Measure the size of the burned piece of wood - this will be the size of your heat exchanger.

The size of the focus point will determine how much copper tubing you will need. The author needed 6 meters of pipe with a spot size of 13 cm.

Rotating mechanism I think that perhaps, instead of a rolled tube, you can put a radiator from a car heater; there are quite small radiators. The radiator should be blackened for better heat absorption. If you decide to use a tube, you must try to bend it without kinks or kinks. Usually, for this purpose, the tube is filled with sand, closed on both sides and bent on some mandrel of a suitable diameter. The author poured water into the tube and put it in freezer, with the open ends facing up to prevent water from leaking out. The ice in the tube will create pressure from the inside, which will avoid kinks. This will allow the pipe to be bent with a smaller bend radius. It must be rolled into a cone; each turn should be slightly larger in diameter than the previous one. You can solder the collector turns together for a more rigid structure. And don't forget to drain the water after you're done with the manifold so you don't get scalded by steam or hot water after you put it back in place.

Step 4. Putting everything together and trying it out.

Installation Assembly Now you have a mirror parabola, sun tracking module placed in a waterproof container, or plastic container, complete collector. All that remains to be done is to install the collector in place and test it in operation. You can go further and improve the design by making something like a pan with insulation and putting it on the back of the manifold. The tracking mechanism must track movement from east to west, i.e. turn towards the sun during the day. And the seasonal positions of the luminary (up/down) can be adjusted manually once a week. You can, of course, add a tracking mechanism vertically - then you will get almost automatic operation installations. If you plan to use the water to heat a pool or as hot water in the water supply, you will need a pump that will pump water through the collector. If you heat a container of water, you must take measures to avoid the water boiling and the tank exploding. This can be done using an electronic thermostat, which, if the set temperature is reached, will move the mirror away from the sun using a tracking mechanism.

I would like to add that when using a collector in winter, you need to take measures to prevent the water from freezing at night and in inclement weather. To do this, it is better to make a closed cycle - on one side there is a collector, and on the other there is a heat exchanger. Fill the system with oil - it can be heated to a higher temperature, up to 300 degrees, and it will not freeze in the cold. Source

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The most popular ways to use solar energy to heat water are to create flat or vacuum solar collectors. However, there are still methods with a fairly high efficiency rate that help use the sun's energy to heat water. This article will discuss one of these methods, namely the creation of a solar concentrator for hot water supply.

To create a water heating system using a solar reflector, the author needed the following materials: 1) parabolic satellite antenna2) mirror film3) copper tube4) salt5) black heat-resistant paint6) mullite crystal fiber

Let's look at the basics of the system and the stages of creating a solar concentrator. The main advantage of such a system is higher performance: high-quality reflectors focus high density sunlight at one point, which allows you to turn water into steam in a matter of seconds.

To demonstrate the visual power of such systems, I recommend that you familiarize yourself with next video material:

As shown in the video, a small solar concentrator can burn through wood, melt lead, that is, the temperature that occurs at the point of concentration of solar rays is quite high.

However, this system has a number of disadvantages that you need to know before deciding to build such a system.

In order for the reflector to be constantly facing the sun, it is necessary to install special tracking systems that will adjust the reflector relative to the sun throughout the day. These trackers are quite expensive and consume quite a bit of energy.

The effectiveness of the concentrator is highly dependent on the cleanliness of the reflective surface, so mirrors require keeping them clean.

If these shortcomings do not bother you, then to build a hub you will need a parabolic satellite antenna, and it is not particularly important whether it is a direct-focus or offset model. The main thing is the correct parabola, which will concentrate all the caught rays into one point. In principle, you can even make something like an antenna yourself from sheets of cardboard, but the effectiveness of such a system greatly depends on the quality of the parabola.

After cleaning the surface of the antenna, the author proceeded to cover it with mirror film. It is best to use a metallized film with an adhesive layer to create a mirror surface. It is quite simple to cover the surface with such a film, following the principle of self-adhesive wallpaper, but you can also use pieces of mirrors to create a reflective surface on the antenna.

Since the satellite antenna itself has a curved shape, it is not entirely reasonable to try to glue a single piece of film. Therefore, before pasting, the author cut the film into thin strips. Thanks to this approach, it was possible to cover the entire surface of the antenna fairly smoothly and with high quality.

After the antenna acquires mirror surface it is necessary to determine the focusing point, it will be the place of concentration of reflected sunlight from the antenna surface. Usually the focusing point of a solar antenna is located right in the area of the converter, but if you built a parabola yourself, then the easiest way to determine the focusing point is using experimental method. It is necessary to take a thicker piece of plywood and gradually move it away from the concentrator until the sunspot on it decreases, as soon as it is minimal, this will be the focusing point of the sun's rays. The main thing to remember is that high temperatures are concentrated in this place, so you need to be careful and wear protective equipment: leather gloves, a welding mask or sunglasses.

Next you need to make a heat exchanger that will communicate the temperature to the water. For this, the author used a copper tube. He tamped the salt into it and began to wrap more pipes around it. Salt inside the copper tube is needed to prevent the pipe from being flattened during winding.

The author notes that in order to use maximum energy from the sun, it would not hurt to paint the heat exchanger black. Since the heat exchanger will experience high temperatures, heat-resistant paint must be used for painting.

Also, to increase efficiency, it is necessary to thermally insulate the heat sink so that it does not cool down from the wind. Below is a diagram of an insulated heat sink:

Use fire-resistant materials to insulate the heat sink, as heat will be concentrated in this area. The author of this concentrator used mullite crystal fiber for these purposes, which is used in gas furnaces And muffle furnaces. The glass must also be tempered so as not to deform due to temperature.

The heat sink was made on the principle of water cooling radiators for computers. It is made according to the size of the focal point spot of the concentrator.

Below is the solar concentrator connection diagram:

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Solar thermal concentrator. Solar energy.

Everyone is interested in alternative energy large quantity great minds. I'm not an exception. 🙂

It all started with simple question: “Is it possible to turn a brushless motor into a generator?” - Yes. Why? -To make a wind generator.

A windmill for generating electricity is not a very convenient solution. Variable wind force, charging device, batteries, inverters, a lot of inexpensive equipment. In a simplified scheme, a windmill copes “excellently” with heating water. Because the load is ten, and it is absolutely not demanding on the parameters of the electricity supplied to it. You can get rid of complex, expensive electronics. But calculations showed significant costs for the design in order to spin up a 500 Watt generator. The power carried by the wind is calculated using the formula P=0.6*S*V3, where: P – power, WattS – area, m2V – wind speed, m/s

A wind blowing 1 m2 at a speed of 2 m/s “carries” 4.8 watts of energy. If the wind speed increases to 10 m/s, the power will increase to 600 Watts. The best wind generators have an efficiency of 40-45%. Taking this into account, for a 500 Watt generator with a wind of, say, 5 m/s. The area swept by the wind generator propeller will be required to be about 12 sq.m. Which corresponds to a screw with a diameter of almost 4 meters! A lot of money is of little use. Add here the need to obtain a permit (noise limit). By the way, in some countries the installation of a wind turbine must be coordinated even with ornithologists.

But then I remembered about the Sun! It gives us a lot of energy. I first thought about this after flying over a frozen reservoir. When I saw a mass of ice more than a meter thick and measuring 15 by 50 kilometers, I thought: “That’s a lot of ice!” How long does it have to be heated to melt it!?” And the Sun will do all this in fifteen days. In reference books you can find the energy density that reaches the surface of the earth. A figure of about 1 kilowatt per square meter sounds tempting. But this is at the equator on a clear day. How realistic is it to utilize solar energy for household needs in our latitudes (the central part of Ukraine), using available materials?

What real power, taking into account all losses, can be obtained from this square meter?

To clarify this issue, I made the first parabolic heat concentrator from cardboard (focus in the parabola bowl). I pasted over the pattern from the sectors with regular food foil. It is clear that the quality of the surface, and even the reflective abilities of the foil, are very far from ideal.

But the task was precisely to heat a certain volume of water using “collective farm” methods in order to find out what power could be obtained taking into account all the losses. The pattern can be calculated using the Exel file ParabAnt-v2.rar, which I found on the Internet from those who like to build parabolic antennas on their own. Knowing the volume of water, its heat capacity, initial and final temperatures, you can calculate the amount of heat spent on heating it. And, knowing the heating time, you can calculate the power. Knowing the dimensions of the concentrator, you can determine what practical power can be obtained from one square meter of surface on which sunlight falls.

As a volume for water, we took half an aluminum can, painted black on the outside.

A container of water is placed at the focus of a parabolic solar concentrator. The solar concentrator is oriented towards the Sun.

Experiment No. 1

was held around 7 a.m. in late May. Morning is far from an ideal time, but just in the morning the Sun shines through the window of my “laboratory”.

With a parabola diameter of 0.31 m, calculations showed that a power of about 13.3 Watts was obtained. Those. at least 177 Watt/sq.m. It should be noted here that a round open jar is far from being the most the best option to get a good result. Part of the energy is spent on heating the can itself, part is radiated into the environment, including being carried away by air currents. In general, even in such far-from-ideal conditions, you can at least get something.

Experiment No. 2

For the second experiment, a parabola with a diameter of 0.6 m was made. Metallized tape purchased at a hardware store was used as its mirror. Its reflective qualities are marginally better than aluminum food foil.

The parabola had a longer focal length (focus outside the bowl of the parabola).

This made it possible to project the rays onto one surface of the heater and obtain in focus high temperature. A parabola easily burns through a sheet of paper in a few seconds. The experiment took place around 7 a.m. in early June. According to the results of the experiment with the same volume of water and the same container, I received a power of 28 Watts, which corresponds to approximately 102 Watts/m2. This is less than in the first experiment. This is explained by the fact that the sun's rays from the parabola did not fall optimally on the round surface of the jar everywhere. Some of the rays passed by, some fell tangentially. The jar was cooled by the fresh morning breeze on one side, while it was heated on the other. In the first experiment, due to the fact that the focus was inside the bowl, the jar was heated from all sides.

Experiment No. 3

Having realized that a decent result can be obtained by making the right heat sink, we made next construction: a tin can inside is painted black and has pipes for water supply and drainage. Hermetically sealed with transparent double glass. Thermally insulated.

The general scheme is this:

Heating occurs as follows: rays from the solar concentrator (1) penetrate through the glass into the heat sink can (2), where, hitting the black surface, they heat it. Water, in contact with the surface of the jar, absorbs heat. Glass does not transmit infrared (thermal) radiation well, so heat radiation losses are minimized. Because the glass warms up over time warm water, and begins to radiate heat, double glazing was applied. The ideal option is if there is a vacuum between the glasses, but this is a difficult task to achieve at home. WITH reverse side The can is thermally insulated with polystyrene foam, which also limits the radiation of thermal energy into the environment.

The heat receiver (2) is connected to the tank (3) using tubes (4.5) (in my case plastic bottle). The bottom of the tank is 0.3m above the heater. This design ensures convection (self-circulation) of water in the system.

Ideally, the expansion tank and pipes should also be thermally insulated. The experiment took place around 7 a.m. in mid-June. The results of the experiment are as follows: Power 96.8 Watt, which corresponds to approximately 342 Watt/m2.

Those. The efficiency of the system has improved by more than 3 times only by optimizing the design of the heat sink!

When carrying out experiments 1,2,3, aiming the parabola at the sun was done manually, “by eye”. The parabola and heating elements were held by hand. Those. the heater was not always in the focus of the parabola, since the person’s hands get tired and begin to look for a more comfortable position, which is not always correct from a technical point of view.

As you may have noticed, efforts were made on my part to provide disgusting conditions for the experiment. Far from it ideal conditions, namely: – not ideal surface of the concentrators – not ideal reflective properties of the surfaces of the concentrators – not ideal orientation to the sun – not ideal position of the heater – not ideal time for the experiment (morning)

could not prevent us from obtaining a completely acceptable result for installation from scrap materials.

Experiment No. 4

Further a heating element was fixed motionless relative to the solar concentrator. This made it possible to increase the power to 118 Watts, which corresponds to approximately 419 Watts/m2. And this is in the morning! From 7 to 8 am!

There are other methods of heating water using solar collectors. Collectors with vacuum tubes are expensive, and flat ones have large temperature losses in the cold season. The use of solar concentrators can solve these problems, but requires the implementation of a mechanism for orientation to the Sun. Each method has both advantages and disadvantages.

One of the issues that needs to be resolved on the way to the practical use of solar concentrators is the reduction of its windage. Those. the concentrator must withstand wind loads. To reduce windage, you can use concentrators assembled from individual segments. Such mirror concentrators can be quite flat compared to a parabola bowl, and the “hole” structure reduces their windage.

I know: DIY solar concentrator - SolarNews

The main advantage of the concentrator is its high heating efficiency. The power of the reflector is capable of focusing energy at one point in sunny weather, sufficient to boil water within a few seconds.

The main disadvantages of such a system are the need to constantly monitor the sun (otherwise the efficiency of the concentrator drops to zero) and polishing and removing dirt from the surface.

To make a solar reflector with your own hands you will need:

1. Unnecessary parabolic antenna (you can also find instructions on the Internet for making parabolic dishes yourself).

2. Metallized mirror film with an adhesive layer (or pieces of mirrors for those who are especially keen)

3. Heat sink - a piece of copper tube twisted into a spiral - and inlet/outlet pipes.

4. Heat exchange tank (if necessary).

5. In the case of using a homemade paraboloid, a mount for the heat sink. If an antenna is used, the heat sink can be secured at the converter mounting location.

Stages of solar concentrator production:

1. Clean the surface of the satellite dish or homemade paraboloid from dirt and grease. Make holes in the center for the tubes.

2. Paste the mirror film cut into thin strips. Thin strips are necessary in order to cover the curved surface of the antenna as tightly as possible without joints, visible seams or irregularities (do not forget to make holes for the tubes).

Applying a mirror film to the cleaned surface of the plate

The result of pasting a paraboloid

3. Fix the heat sink painted with black heat-resistant paint at the focal point and bring the inlet and outlet tubes to it.

Fixing the heat sink at the focus of the concentrator

4. Pour liquid into the heat exchange tank and install the solar concentrator perpendicular to the sun.

Important: It must be remembered that the temperature at the concentration point can reach 300-500 degrees, so when working with a solar parabolic concentrator, you must follow safety precautions - work in protective clothing (leather or canvas gloves) and sunglasses or a welding mask.

The scheme for heating water using a homemade solar concentrator looks something like this:

Diagram of a homemade solar concentrator with a heat exchange tank

Based on materials from solarsistem.ru

Well, this is what the work of a homemade solar concentrator looks like in the video (very similar to the experiment with a “solar boiler”, isn’t it?):

solar-news.ru How to change a bathroom faucet with your own hands

Do-it-yourself heating from polypropylene pipes

People have been using a huge amount of free energy from the sun, water and wind and much more that nature can provide for a long time. For some, this is a hobby, while others cannot survive without devices that can extract energy “out of thin air.” For example, in African countries, solar panels have long become a life-saving companion for people; solar-powered irrigation systems are being introduced in arid villages, “solar” pumps are being installed on wells, etc.

In European countries the sun does not shine so brightly, but summer is quite hot, and it is a pity when the free energy of nature is wasted. There are successful designs of solar-powered ovens, but they use solid or prefabricated mirrors. Firstly, this is expensive, and secondly, it makes the structure heavier and therefore not always convenient to use, for example, when a light weight of the finished concentrator is required.
An interesting model of a homemade parabolic solar concentrator was created by a talented inventor.
It does not require mirrors, so it is very light and will not be a heavy load on a hike.

To create a homemade solar concentrator based on film, very few things are required. All of them are sold at any clothing market.
1. Self-adhesive mirror film. It has a smooth, shiny surface and is therefore an excellent material for the mirror part of a solar oven.
2. A sheet of chipboard and a sheet of hardboard of the same size.
3. Thin hose and sealant.

How to make a solar oven?

First, two rings are cut out from a chipboard of the size you need using a jigsaw, which must be glued to each other. There is one ring in the photo and video, but the author indicates that he later added a second ring. According to him, it would have been possible to limit ourselves to one, but the space had to be increased to form a sufficient concavity of the parabolic mirror. Otherwise the beam focus will be too far away. A circle of hardboard is cut to the size of the ring to form the back wall of the solar concentrator.
The ring should be glued to the hardboard. Be sure to coat everything well with sealant. The structure must be completely sealed.
Carefully make a small hole on the side so that there are even edges, into which tightly insert a thin hose. To ensure a tight seal, the connection between the hose and the ring can also be treated with sealant.
Stretch a mirror film over the ring.
Pump out the air from the installation body and thus form a spherical mirror. Bend the hose and clamp it with a clothespin.
Make a convenient stand for the finished concentrator. The energy of this installation is enough to melt an aluminum can.

Attention! Parabolic solar reflectors can be dangerous and can cause burns and eye damage if not handled carefully!
Watch the solar oven manufacturing process in the video.

Material used from the site zabatsay.ru. How to make a solar battery - .