DIY solar concentrator. Solar Energy Concentrators Parabolic Mirror Manufacturing

In my distant childhood, I came across a reader on astronomy from those even more distant years, which I did not find when this astronomy was a subject at school. I read it to the holes and dreamed of a telescope to look at the night sky with at least one eye, but it did not work out. He grew up in a village where there was neither knowledge nor a mentor for this. So this hobby went away. But with age, I discovered that the desire remained. I searched the Internet, it turns out there are people who are keen on telescopic construction and assemble telescopes, and what kind of telescopes, and from scratch - a lot. From specialized forums I gathered information, theory, and decided to build a small telescope for a beginner.

Ask me earlier what a telescope is, I would say - a pipe, you look on one side, the other is directed to the object of observation, in a word, a telescope, but larger in size. But it turns out that for telescopic construction they use basically a different design, which is also called a Newtonian telescope. With a lot of advantages, it does not have many disadvantages compared to other telescope designs. The principle of its operation is clear from the figure - the light of distant planets falls on a mirror, which ideally has a parabolic shape, then the light is focused and carried out of the pipe using the second, set at 45 degrees in relation to the axis, diagonally, mirror, which is called so - diagonal. Then the light enters the eyepiece and into the eye of the observer.

A telescope is a precision optical instrument, so care must be taken in manufacturing. Before that, it is necessary to make calculations of the structure and installation locations of the elements. On the Internet, there are online calculators for calculating telescopes and it's a sin not to use it, but it doesn't hurt to know the basics of optics either. I liked the calculator.

To make a telescope, in principle, nothing supernatural is needed, I think that any household person in the back room has a small lathe, at least for wood, and even for metal. And if there is also a milling machine, I envy with white envy. And it is not at all uncommon now for home-made CNC laser machines for cutting on plywood and a 3D printing machine. Unfortunately, I have nothing on the farm from all of the above, except for a hammer, a drill, a hacksaw, a jigsaw, a vice and small hand tools, plus a bunch of cans, trays with a scattering of tubes, bolts, nuts, washers and other garage scrap metal, which seems to be and it is necessary to throw it out, but it's a pity.

When choosing the size of the mirror (diameter 114mm), it seems to me that I chose the golden mean, on the one hand, this size of the chassis is not quite small, on the other hand, the cost is not so huge that in case of a fatal failure, financially suffer. Moreover, the main task was to touch, understand and learn from mistakes. Although, as they say in all forums, the best telescope is the one in which one is observing.

And so, for my first, hopefully not the last, telescope, I chose a spherical main mirror with a diameter of 114mm and an aluminum coating, a focus of 900mm and a diagonal mirror in the shape of an oval with a small diagonal of one inch. With this mirror size and focal length, the differences in the shape of the sphere and the parabola are negligible, so an inexpensive spherical mirror can be used.

The inner diameter of the tube according to Navashin's book, The Telescope of the Amateur Astronomer (1979), for such a mirror should be at least 130mm. Of course, bigger is better. You can make the pipe yourself from paper and epoxy, or from tin, but it's a sin not to use ready-made cheap material - this time a meter-long PVH sewer pipe DN160, bought for 4.46 euros in a building store. The wall thickness of 4mm seemed to me sufficient in terms of strength. Sawing and processing is easy. Although there is also a 6mm wall thickness, it seemed to me a bit heavy. In order to cut, I had to brutally sit on it, no residual deformations were observed by eye. Of course, the aesthetes will say fi, how you can look at the stars through a pipe for an Aries. But for real handlers this is not an obstacle.

Here she is, beauty

Knowing the parameters of the mirror, you can calculate the telescope on the aforementioned calculator. Not everything is clear right away, but as the creation progresses, everything falls into place, the main thing, as always, is not to get hung up on theory, but to combine it with practice.

Where to begin? I started, in my opinion, with the most difficult thing - the diagonal mirror mount. As I already wrote, making a telescope requires precision, but that does not negate the possibility of adjusting the position of the same diagonal mirror. Without fine adjustment - nothing. There are several diagonal mirror mounting schemes, on one stand, on three stretch marks, on four and others. Each has its own pros and cons. Since the dimensions and weight of my diagonal mirror, and hence its mountings, let's face it, are small, I chose a three-beam mount system. I used a 0.2mm thick stainless steel adjusting sheet as stretchers. As reinforcement, I used copper couplings for a 22mm pipe with an outer diameter of 24mm, slightly smaller than the size of my diagonal, as well as an M5 bolt and M3 bolts. The central M5 bolt has a tapered head, which, when pushed into the M8 washer, works like spherical bearing, and allows you to tilt the diagonal mirror during adjustment with the M3 adjusting bolts. First I soldered the washer, then cut it roughly at an angle and adjusted it to 45 degrees on a sheet of coarse sandpaper. Both parts (one filled completely, the other 5mm through the hole) took less than 14ml of a five-minute two-component epoxy glue Moment. Since the dimensions of the assembly are small, it is very difficult to place everything and for all this to work properly, the adjustment arm is not enough. But it turned out very, very not bad, the diagonal mirror is adjusted smoothly enough. I dipped bolts and nuts in hot wax so that the resin would not stick when pouring. Only after the manufacture of this unit did I order the mirrors. The diagonal mirror itself was glued to double-sided foam tape.

There are some photos of this process under the spoiler.

Diagonal Mirror Assembly

The manipulations with the pipe were as follows: I sawed off the excess, well, since the pipe has a bell of a larger diameter, I used it to strengthen the area of attachment of the diagonal braces. I cut out the ring and put it on the pipe with epoxy. Although the rigidity of the pipe is sufficient, in my opinion it will not be superfluous. Further, as the components arrived, I drilled and cut holes in it, pasted it over with a decorative film on the outside. Highly important point- painting of the pipe from the inside. It should be such that it absorbs light as much as possible. Unfortunately, the paint on sale, even matte, is not suitable at all. There are specials. paints for this, but they are expensive. I did this - on the advice of one forum, I covered the inside with paint from a spray can, then poured rye flour into the pipe, closed the two ends with a film, twisted it well - shook it, shook out what did not stick and blew it out with paint again. It turned out very well, you look like a chimney.

The main mirror was mounted using two 12mm thick plywood disks. One with a diameter of 152mm for the tube, the second with a diameter of the main mirror 114mm. The mirror rests on three circles of leather glued to the disk. The main thing is that the mirror is not rigidly clamped, I screwed on the corners, wrapped them with electrical tape. The mirror itself is held by rails. Two discs have the ability to move relative to each other to adjust the main mirror using three M6 adjusting bolts with springs and three locking bolts, also M6. According to the rules, there must be holes in the disks to cool the mirror. But since my telescope will not be stored at home (it will be in the garage), then temperature equalization is not relevant either. In this case, the second disc also acts as a dustproof rear cover.

In the photo, the mount is already with a mirror, but without the rear disc.

Photo of the manufacturing process itself.

Mounting the main mirror

I used a Dobson mount as a support. There are a lot of different modifications on the Internet, depending on the availability of tools and materials. Consists of three parts, the first in which the telescope tube itself is clamped -

The orange circles are sawn-off rounds of pipes, into which are inserted circles of 18mm plywood and filled with epoxy resin. The result is a component part of a plain bearing.

The second - where the first is placed, allows the telescope tube to move vertically. And the third is a circle with an axis and legs, on which the second part is placed, which allows it to rotate.

Pieces of Teflon are screwed in the places where the parts are supported, allowing the parts to be easily and without jerks moving relative to one another.

After assembly and primitive tuning, the first tests were passed.

The problem immediately appeared. I ignored the advice of smart people not to drill holes for the main mirror mounts without testing. It's good that I sawed the pipe with a margin. The focal length of the mirror turned out to be not 900mm, but about 930mm. I had to drill new holes (the old ones were sealed with electrical tape) and move the main mirror further. I simply could not catch anything in focus, I had to raise the eyepiece itself from the focuser. The disadvantage of this solution is that the fastening and adjusting bolts from the end do not hide in the pipe. but stick out. In principle, not a tragedy.

I took it off my hand with my mobile phone. At that time, there was only one 6mm eyepiece, the degree of magnification is the ratio of the focal lengths of the mirror and the eyepiece. In this case, it turns out 930/6 = 155 times.
Test number 1. To the object 1 km.

Number two. 3 km.

The main result has been achieved - the telescope is working. It is clear that better alignment is needed to observe the planets and the Moon. A collimator was ordered for her, well, another 20mm eyepiece, and a filter for the full moon. After that, all the elements from the pipe were removed and put back more carefully, stronger and more accurately.

And finally, the goal of all this is observation. Unfortunately, there were practically no starry nights in November. Of the objects that he managed to observe only two, the Moon and Jupiter. The moon does not look like a disc, but a majestically passing landscape. With a 6mm eyepiece, only part of it can be accommodated. And Jupiter with its satellites is just a fairy tale, given the distance that separates us. It looks like a striped ball with satellite stars on the line. It is impossible to distinguish the colors of these lines; here you need a telescope with a different mirror. But all the same - fascinating. To photograph objects you need both optional equipment and another type of telescope - high-aperture with a short focal length. Therefore, here is only a photo from the vastness of the Internet, accurately illustrating what is visible with such a telescope.

Unfortunately, to observe Saturn, you have to wait for spring, but for now, Mars and Venus are in the near future.

It is clear that mirrors are by no means all of the building costs. Below is a list of what was purchased besides this.

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

In fact, the device, invented by the great Greek, was the first concentrator of solar radiation, which collected the sun's rays into one energy beam. And in 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 concepts, 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 hub is familiar to everyone from childhood. This is an ordinary biconvex lens, with which it was possible to burn out various figures, inscriptions, even whole pictures, when the sun's rays were collected by such a lens into a small point on wooden board, a piece 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 low cost, are practically used very little, since they have large dimensions. Their use is justified where the dimensions of the concentrator are not critical.

Refractory Solar Concentrator

A prismatic concentrator of solar radiation is devoid of 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 rear face reflects, and radiation is already coming out of the lateral 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, reflex concentrators work on the principle of collecting the reflected energy into an energy beam. sunlight... By 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 given by parabolic concentrators. But to build systems solar heating mainly flat or parabolic cylindrical systems are used.

Parabolic (reflex) solar concentrators

Practical application of solar concentrators

Actually, the main task of any solar concentrator- to collect the sun's radiation into a single energy beam. And you can use this energy in different ways. It is possible to heat water with 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 for additional lighting. solar panels to increase the output power. And it can be used as an external heat source for Stirling engines. The parabolic concentrator provides a focus temperature of the order of 300 ° C - 400 ° C. If, for example, a stand for a teapot and frying pans are placed in the focus of such a relatively small mirror, then you will get a solar oven, on which you can very quickly cook food, boil water. A focused heater with a coolant will allow you to quickly heat even running water, which can then be used in economic purposes, for example, for a shower, washing dishes.

Simplest schemes water heating by solar concentrator

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

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

The main disadvantage of a parabolic concentrator is that it must be constantly oriented towards the sun. In industrial helium plants, special tracking systems are used that rotate mirrors or refractors to follow the movement of the sun, thereby ensuring the reception and concentration of the maximum amount of solar energy. For individual use, it will hardly be advisable to use such tracking devices, since their cost can significantly exceed the cost of a simple reflector on an ordinary 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 an installation site and prepare the base and fasteners accordingly. Thoroughly wash the antenna, dry it, stick a mirror film on the receiving side of the plate.

In order for the film to lie flat, without wrinkles and folds, it should be cut into strips no more than 3 - 5 centimeters wide. If the concentrator is supposed to be used as a solar oven, it is recommended to cut a hole with a diameter of about 5 - 7 centimeters in the center of the plate. A bracket with a cookware support (burner) will be passed through this hole. This will keep the food container immobile when the reflector is turned in the sun.

If the plate is small in diameter, it is also recommended to cut the strips into pieces about 10 cm long. Glue each piece separately, carefully adjusting the joints. When the reflector is ready, it should be mounted on a support. After that, it will be necessary to determine the focal point, since the optical focal 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 arm yourself with dark glasses, a wooden board and thick gloves. Then you need to direct the mirror directly to the sun, catch a sunbeam on the board and, bringing the board closer or away from the mirror, find the point where this bunny will have minimum dimensions- a small point. Gloves are needed in order to protect your hands from burns if they accidentally fall into the range of the beam. Well, when the focal point is found, it only remains to fix and mount it. necessary equipment.

Options self-made solar concentrator there are many. In the same way, you can make a Stirling engine from the materials at hand. And this engine can be used for a variety of purposes. How long will there be enough imagination, desire and patience.

Start-up company GoSol is committed to making solar energy available to everyone on a global scale. To this end, she set up an initiative to develop and distribute instructions for assembling solar concentrators from local materials that could be effective sources of heat for cooking, washing, heating water and heating.

“GoSol.org's mission is to eradicate energy poverty and minimize the impact of global warming by expanding our DIY technology and breaking down all barriers to free access to solar energy. energy. With your help, we want to engage communities, entrepreneurs and craftsmen to harness the world's most powerful energy source. All materials and tools necessary for the implementation of these technologies have already been produced and are abundant 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. On this moment The initiative has raised about $ 27,000 and just recently GoSol released its first solar concentrator instruction manual.

Read also: Ripasso solar concentrator - the most efficient way to convert solar energy?

Free step by step guide contains all the information you need 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 plant from GoSol, will take up approximately 1.5 cubic meters of space. The work on its manufacture will take about a week. The materials for its construction will be iron corners, plastic boxes, steel rods, and the main working element - a reflecting hemisphere - is proposed to be made from pieces of ordinary bathroom mirrors.

The solar concentrator can be used for baking, frying, heating water or preserving food through dehydration. The device can also serve as a demo example. effective 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 burning wood with clean energy from the sun.

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

A free solar concentrator instruction is available on the GoSol website, and in order 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 advance faster and on a larger scale, then you can support the company financially - the startup is still accepting cash contributions, the reward for which will depend on the amount donated.

See also: Ukrainian solar concentrator "Diversity" - freely available instructions

Video: GoSol.org Free The Sun Campaign for Builders

ecotechnica.com.ua

Homemade solar concentrator made of mirror film

A huge amount of free energy of the sun, water and wind and many other things that nature can give, people have been using for a long time. For some, this is a hobby, while others cannot survive without devices that can extract energy "from the 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 the summer is quite hot, and it is a pity when the free energy of nature is wasted. There have been successful designs of solar powered stoves, but they use one-piece or prefabricated parabolic mirrors. Firstly, it is expensive, and secondly, it makes the structure heavier and therefore not always convenient in operation, for example, when a light weight of the finished concentrator is required. An interesting model of a home-made parabolic solar concentrator was created by a talented inventor. It does not require mirrors to make it, therefore it is very light and will not be a heavy burden on a hike.

Very few things are required to create a homemade film-based solar concentrator. All of them are sold in 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 chipboard sheet 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 of a chipboard of the size you need with 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, one could be limited to one, but it was necessary to increase the space to form a sufficient concavity of the parabolic mirror. Otherwise, the focus of the beam 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. From the side, carefully so that there are even edges, make a small hole into which you firmly insert a thin hose. For tightness, the connection of the hose and the ring can also be sealed. Pull a mirror film over the ring. Pump the air from the unit body and thus form a spherical mirror. Bend the hose and pinch it with a clothespin. Make a comfortable stand for the finished hub. 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 handled carelessly! Watch the video for making a solar stove.

Used material from the site zabatsai.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 the most powerful source of free energy, but no one understood how to use this energy. According to the ancient writers Plutarch and Polybius, the first person to practically use solar energy was Archimedes, who, with the help of some optical devices invented by him, managed to collect the sun's rays into a powerful beam and burn the Roman fleet.

Refractory Solar Concentrator

Unlike refractory, reflex concentrators work on the principle of collecting reflected sunlight into an energy beam. By 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 given by parabolic concentrators. But for the construction of solar heat supply systems, mainly flat or parabolic-cylindrical systems are used.

Parabolic (reflex) 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 different ways. It is possible to heat water with 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 for additional lighting of solar panels to increase the power output. And it can be used as an external heat source for Stirling engines. The parabolic concentrator provides a focus temperature of the order of 300 ° C - 400 ° C. If, for example, a stand for a teapot and frying pans are placed in the focus of such a relatively small mirror, then you will get a solar oven, on which you can very quickly cook food, boil water. A focused heater with a coolant will allow you to quickly heat up even running water, which can then be used for household purposes, for example, for a shower, washing dishes.

The simplest schemes for heating water with a solar concentrator

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

How to make your own solar concentrator

Homemade solar concentrator - oven

To determine the focal point, you need to arm yourself with dark glasses, a wooden board and thick gloves. Then you need to direct the mirror directly to the sun, catch a sunbeam on the board and, bringing the board closer or away relative to the mirror, find the point where this bunny will have its minimum size - a small point. Gloves are needed in order to protect your hands from burns if they accidentally fall into the range of the beam. Well, when the focal point is found, it will only be necessary to fix it and mount the necessary equipment.

There are many options for self-manufacturing solar concentrators. In the same way, you can make a Stirling engine from the materials at hand. And this engine can be used for a variety of purposes. How long will there be enough imagination, desire and patience.

solarb.ru

This homemade product 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 the 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 N latitude.

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

Parabolic antenna.

Any antenna can be used - iron, plastic or fiberglass. The antenna should be panel type, not mesh antenna. Antenna area and shape are important here. Remember, 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 rotary mechanism for the antenna assembly. It can be ordered on Ebay or Aliexpress.

You will need a roll of aluminum foil or lavsan mirror film used for greenhouses. The glue with which the film will stick to the parabola.

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

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

All you need to do is attach the lavsan mirror film or aluminum foil to the antenna mirror.

Such a film can be ordered on Aliexpress, if suddenly you do not find the film in stores.

This is almost as easy as it sounds. You just need to take into account that if the antenna, for example, is 2.5 m in diameter, and the film is 1 m wide, then you do not need to cover the antenna with a film in two passes, folds and irregularities will form, which will worsen the focusing of solar energy. Cut it out in small strips and attach it to the antenna with glue. Make sure the antenna is clean before applying tape. If there are places where the paint is swollen, clean them sandpaper... You need to align all the irregularities. Please note that the LNB is removed from its place, otherwise it may melt. After gluing the film and installing the antenna in place, keep your hands or face away from the head mount - 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 operation according to the scheme from the archive

Itself can be made on the basis of the front hub of a VAZ car.

Who cares the photo is taken from here: Rotary mechanism

Step 3 Create a heat exchanger-collector

To make a heat exchanger, you need a copper tube rolled into a ring and placed in the focus of our concentrator. But first we need to know the size of the focal point of the dish. To do this, remove the LNB converter from the plate, leaving the converter mounting racks. Now you need to turn the plate in the sun, after fixing 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 that, turn the antenna away from the sun, remove the board from the mount. All manipulations with the antenna, its turns, are carried out so that you do not accidentally put your hand into the focus of the mirror - this is dangerous, you can get severely 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 tube you will need. The author needed 6 meters of pipe with a spot size of 13 cm.

Swivel mechanism I think that instead of a rolled tube, you can put a radiator from a car stove, there are rather small radiators. The radiator should be blackened for better heat absorption. If you decide to use a tube, you should try to bend it without kinking or kinking. Usually, for this, the tube is filled with sand, closed on both sides and bent on some kind of mandrel. suitable diameter... The author poured water into the tube and put it in freezer with the open ends facing up to prevent water from flowing out. The ice in the tube will create pressure from the inside to avoid kinking. This will allow the pipe to bend with a smaller bend radius. It must be rolled up along a cone - each turn should not be much 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 that you don't get scalded by the steam or hot water after putting it back in place.

Step 4. Putting it all together and trying it out.

Assembly Assembly Now you have a mirror parabola, a sun tracker housed in a waterproof container, or a plastic container, a complete manifold. All that remains to be done is to put the manifold back in place and try it out. 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 around during the day for the sun. And the seasonal positions of the luminary (up / down) can be manually adjusted once a week. You can, of course, add a tracking mechanism in the vertical direction - then you will get an almost automatic operation of the installation. If you plan to use the water to heat the pool or as hot water in the plumbing, you will need a pump that will pump the water through the manifold. If you will heat a container with water, you must take measures to avoid boiling water and an explosion of the tank. This can be done using electronic thermostat, which, in case of achievement set temperature, will deflect the mirror from the sun using the tracking mechanism.

On my own behalf, I will add that when using the collector in winter, it is necessary to take measures so that the water does not freeze at night and in inclement weather. To do this, it is better to make a closed cycle - on one side a collector, and on the other a heat exchanger. Fill the system with oil - it can be heated to a higher temperature, up to 300 degrees, and will not freeze in the cold. A source

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usamodelkina.ru

The most popular ways to use solar energy to heat water is to create flat or vacuum solar collectors. However, there are still methods with a fairly high efficiency index that help to use the energy of the sun to heat water. This article will discuss one such method, 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 antenna 2) mirror film 3) copper tube 4) salt 5) black heat-resistant paint 6) mullite crystal fiber

Consider 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 sun rays 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 the following video material:

As shown in the video, a small solar concentrator can burn wood, melt lead, that is, the temperature that occurs at the point where the sun's rays are concentrated 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 turned towards 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 a lot of energy.

The efficiency of a concentrator is highly dependent on the cleanliness of the reflective surface, so mirrors need to be kept clean.

If these shortcomings do not scare you, then to build a concentrator you need a parabolic satellite dish, 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 to one point. In principle, you can even make a kind of antenna yourself from sheets of cardboard, but the effectiveness of such a system depends very much on the quality of the parabola.

After cleaning the antenna surface, the author proceeded to pasting it with a mirror film. It is best to use a metallized film with an adhesive layer to create a mirror surface. It is quite simple to glue the surface with such a film on 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 dish 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 paste over the entire surface of the antenna quite smoothly and in quality.

After the antenna acquires mirror surface it is necessary to determine the focal point, it will be the place of concentration of the reflected sunlight from the antenna surface. Usually the focal point at the solar antenna is located just in the area of the converter, but if you built the parabola yourself, then the easiest way to determine the focal point is using the experimental method. It is necessary to take a piece of thicker plywood and gradually move it away from the concentrator until the sun spot 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 temperature is 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 report the temperature to the water. For this, the author used a copper tube. He tamped salt into it, and began to wind more around the pipe. The salt inside the copper tube is needed to prevent the tube from flattening during winding.

The author notes that in order to use the maximum energy from the sun, the heat exchanger can be painted black. Since the heat exchanger will experience high temperatures, heat-resistant paint must be used for painting.

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

Use refractory materials to insulate the heat sink, as this area will concentrate the heat. The author of this concentrator used for these purposes mullite-crystalline fiber, which is used in gas forges and muffle furnaces... The glass must also be tempered so as not to deform from temperature.

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

Below is the connection diagram of the solar concentrator:

usamodelkina.ru

Solar thermal concentrator. Solar energy.

An increasing number of great minds are interested in alternative energy. I'm not an exception. 🙂

It all started with a simple question: "Is it possible to turn a brushless motor into a generator?" Why? -Make a wind generator.

A wind turbine to generate electricity - not really convenient solution... Variable wind power, chargers, batteries, inverters, a lot of not a penny equipment. In a simplified scheme, the wind turbine copes with water heating very well. For the load is ten, and it is absolutely not picky about the parameters of the electricity supplied to it. You can get rid of complicated expensive electronics. But the calculations showed significant construction costs to spin up the 500 W generator. The power carried by the wind is calculated by the formula P = 0.6 * S * V3, where: P - power, Watt S - area, m2 V - wind speed, m / s

The wind blowing on 1 m2 at a speed of 2 m / s "carries" an energy of 4.8 watts. If the wind speed increases to 10 m / s, then the power will increase to 600 watts. The best wind turbines have an efficiency of 40-45%. With this in mind, for a 500 watt generator with a wind of say 5 m / s. An area swept by the wind turbine propeller is required, 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 limitation). By the way, in some countries the installation of a windmill 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 15 by 50 kilometers in size, I thought: “This is how much ice! How much does it need to be heated to melt it !? " And all this will be done by the Sun in a dozen and a half days. In reference books you can find the density of energy 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 (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 question, I made the first parabolic heat concentrator from cardboard (focus in the parabola bowl). The pattern of the sectors was pasted over with ordinary food foil. It is clear that the surface quality and the reflectivity of the foil are very far from ideal.

But the task was to heat a certain volume of water using the “collective farm” methods in order to find out what power can be obtained taking into account all losses. The pattern can be calculated using the Exel ParabAnt-v2.rar file that 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 temperature, 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, it is possible to determine what practical power can be obtained from one square meter of the surface on which the sunlight falls.

A half of an aluminum can, painted black on the outside, was taken as a volume for water.

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

Experiment # 1

was held at about 7 am at the end of May. Morning is far from 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 W / m2 It should be noted here that a round open pot is far from the best option for getting a good result. Part of the energy is spent on heating the can itself, part is emitted into the environment, including carried away by air currents. In general, even in such far from ideal conditions, you can at least get something.

Experiment # 2

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

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

This made it possible to project the rays onto one surface of the heater and obtain a high temperature in focus. The parabola can easily burn through a sheet of paper in a matter of seconds. The experiment was carried out at about 7 am in early June. According to the results of the experiment with the same volume of water and the same container, a power of 28 watts was obtained, which corresponds to approximately 102 watts / sq.m. This is less than in the first experiment. This is due to the fact that the sun's rays from the parabola fell on the round surface of the can not everywhere optimally. Some of the rays passed by, some fell tangentially. The jar was cooled by the fresh morning breeze on one side, while it was warmed up 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 # 3

Realizing that a decent result can be obtained by making the right heat sink, the following design was made: a tin can inside, painted black, has pipes for supplying and removing water. Hermetically sealed with transparent double glass. Thermally insulated.

The general scheme is as follows:

Heating takes place as follows: rays from the solar concentrator (1) penetrate through the glass into the can of the heat collector (2), where, falling on the black surface, they heat it up. Water, in contact with the surface of the can, absorbs heat. Glass poorly transmits infrared (thermal) radiation, so losses due to heat radiation are minimized. Since over time the glass heats up with warm water and begins to radiate heat, double glazing was used. Ideal if there is a vacuum between the glasses, but this is an elusive task at home. On the reverse side of the can is thermally insulated with foam, which also limits the radiation of thermal energy into the environment.

The heat receiver (2) is connected with pipes (4,5) to the tank (3) (in my case plastic bottle). The bottom of the tank is 0.3m above the heater. This design provides convection (self-circulation) of water in the system.

Perfectly expansion tank and the tubes must also be thermally insulated. The experiment was carried out at about 7 am in the middle of June. The results of the experiment are as follows: Power 96.8 watts, which corresponds to approximately 342 watts / sq. M.

Those. the efficiency of the system has improved more than 3 times only due to the optimization of the design of the heat sink!

During experiments 1, 2, 3, the parabola aiming at the sun was done manually, "eyeballs". The parabola and heating elements were held by hands. Those. the heater was not always in the focus of the parabola, as a 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 have been made on my part to provide a disgusting environment for the experiment. Far from ideal conditions, namely: - not perfect surface concentrators - not ideal reflective properties of concentrator surfaces - not ideal orientation to the sun - not ideal position of the heater - not ideal time for experiment (morning)

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

Experiment # 4

Next, the heating element was fixed motionlessly relative to the solar concentrator. This made it possible to increase the power to 118 watts, which corresponds to approximately 419 watts / sq.m. And this is in the morning! From 7 to 8 in the morning!

There are other methods of heating water using Solar collectors... Collectors with vacuum tubes are expensive, while flat collectors have high temperature losses during the cold season. The use of solar concentrators can solve these problems, however, it 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 application of solar concentrators is to reduce its windage. Those. the concentrator must withstand wind loads. Hubs assembled from separate segments can be used to reduce windage. Such mirrored concentrators can be quite flat compared to a parabola bowl, and the "perforated" 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 for several seconds.

The main disadvantages of such a system are the need for constant tracking of 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. An unnecessary parabolic antenna (you can also find instructions on how to make parabolic dishes yourself on the Internet).

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

3. Heat receiver - 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 - mount for the heat sink. In the case of using an antenna, the heat sink can be fixed in the place where the converter is attached.

Solar concentrator production steps:

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

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

Sticking a mirror film on 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 pipes to it.

Fixing the heat sink in the focus of the concentrator

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

Important: It must be remembered that the temperature at the point of concentration can reach 300-500 degrees, therefore, when working with a solar parabolic concentrator, you must observe safety measures - 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 like this:

Diagram of a homemade solar concentrator with a heat exchange tank

Based on materials from the site solarsistem.ru

Well, this is how the work of a homemade solar concentrator looks like in the video (very similar to an experiment with a "solar boiler", isn't it?):

solar-news.ru How to change the mixer in the bathroom with your own hands

DIY heating from polypropylene pipes

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

A good mirror will help you see various details of the moon, planets solar system and other objects in deep space, while a poor quality mirror will only give you vague 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 choose to make their own mirrors rather than buy cheap industrial designs. The second reason is that you will gain necessary knowledge for the production of high-quality optical devices, and as you know, you do not have to carry knowledge on your shoulders.

Step 1: Materials

The blank glass is made of a material with a low coefficient of expansion (Pyrex, borosilicate glass, Duran 50, Zerodur, 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: Prepare the workpiece

Glass blanks often come with surface markings. The “round mark” in the lower part is left by the stove, and the upper marks appeared as a result of the temperature difference during the cooling of the glass.

Let's start by finishing the edges of the glass to limit the risk of chipping. A sharpening stone is an excellent tool for this operation. Don't forget about funds individual protection respiratory organs and remember that glass and stone should be moistened with water (since 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 smooth the surface, use a coarse silicon carbide (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 pits and potholes.

Step 3:

This tool will be used to create a concave surface on the glass blank.

Cover the glass plastic wrap... Let's make a cardboard cylinder around the workpiece and fill the gypsum inside. Let it dry, then remove the cardboard. Peel off the glass carefully and process any burrs at the edges.

Step 4: Coating with ceramic tiles

We need a solid surface in order to sand the glass. That is why the bulge of the workpiece must be covered with ceramic tiles.

We glue the tile to the gypsum base with epoxy resin.

Note to avoid placing tiles or holes in the center. Instead, move the tile slightly to avoid any center defect on the mirror surface.

Step 5: start sanding

Put some wet sand on the surface of the tile and start rubbing the glass over it.

After a few passes, turn the mirror and continue sanding in the other direction. This ensures good handling, from all angles and will prevent mistakes.

Step 6:

Continue sanding until you get the desired curve. To estimate the curvature, you must use a calculator from the Sagitta measurement set.

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

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

Focal ratio f / 4.75. Sagitta of my 20 cm mirror is 0.254 cm.

Step 7: smooth the surface

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

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

Moving on to Silicon Carbide # 320. After you've reached this step, you should start seeing some reflections as you peer into the mirror blank.

Step 8:

We need to make another tool for this operation. You can make it out of plaster or thick plywood. She will be covered soft material- resin.

Resin conifers- very sticky and difficult to clean.

Make another cylinder around the base to fit. Melt a large number of resin and pour it into the cylinder. Let the resin cool and remove the cardboard cover. After that, we begin to shape the surface, it is necessary to give it a slight bulge. The created channels will also help you with glass processing.

Step 9: polish

Put some wet cerium powder on top of the resin and start rubbing against it with a mirror. Cerium will penetrate the resin surface. Use a soapy lubricant if needed.

Step 10: making a Foucault tester

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

The tester uses this principle so that you can visually see errors in the range of 1 millionth cm. By adding the Ronchi display 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 in the back allows you to adjust the tilt angle.

Step 11: making the 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 should get a paraboloid.

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

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

There is also a comprehensive checklist of different tricks to correct surface errors.

Step 12: surface inspection with a Foucault tester

This is how the reflection in the Foucault tester looks like, which is equipped with a Ronchi grid.

Depending on the case (the mesh cuts the light before or after the radius of curvature), you can interpret the lines and infer the shape of the surface.

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

Step 14: aluminum

In order to completely complete the craft, it must be sent for aluminizing. The mirror currently reflects only 4% of the light. The 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 an imprint of the center - 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…

Hello everyone! Vitaly Solovey with you. Today my article will be on the topic of parabolic mirrors and the energy of the sun in general. A couple of years ago, on the Internet in the United States, I came across a device that was unique at that time - a parabolic mirror, which is also called a concentrator of direct sunlight. Visually, it resembles a satellite dish with a mirrored surface inside.

The principle of operation of this dish is such that when the sun's rays hit the mirror surface, the rays are reflected and accumulated at one point. This is due to the parabolic shape of the dish and the light beam is reflected at exactly the same angle at which it hit the mirror surface.

With the correct execution of the so-called convex mirror, the temperature in the place of accumulation of rays can reach 2000 degrees Celsius.

In support of this, I will give a video.

The surface of a parabolic mirror can be either solid, that is, without seams, or from pieces of mirrors or reflective film. In the video above, the mirror consisted of 5,800 individual small mirrors. But the difficulty lies in placing them all correctly. Place all 5800 mini mirrors at the correct angle.

Also, the surface can be covered with pieces of reflective silver film, which is also not gud, since due to the numerous seams, the sun's rays are slightly scattered and the effect will be much weaker.

The solution in this situation may be if the convex plate itself is made from several longitudinal parts, on which a reflective film is evenly glued.

In this case, the reflected rays at the most correct angle will focus on the cluster point. But the most effective way production is still a natural glass mirror of a parabolic shape, which, of course, will cost unmeasured for the use of the mirror in everyday life.

Simplest and most effective option What I found is a method of vacuum forming a parabolic mirror.

During gluing, it is better to spread the film with the mirror side to the tabletop, and cover it with a glued dish and press it a little.

Now, to form a parabolic shape for the film, you need to pump out the air from the resulting vessel. To do this, we will drill a hole in any part of the plastic container and insert a bicycle valve there.

Important! The spool is required to be installed reverse side inside out, since we will pump out the air, and not pump it inside the vessel.

And here's what should ideally come out:

That's all for now, in subsequent articles I will talk about other, no less important applications of a parabolic mirror. And finally, a video on how to make a fire using toilet paper and a tablespoon: