DIY solar oven, DIY solar battery. Master Class

III th All-Russian full-time student conference “Eidos. Education”, St. Petersburg, March 24-26, 2016

III All-Russian full-time student conference

"Eidos. Education"

Type of work: research work in natural science

Borgolov Yura, 7B class, Ust-Orda Secondary School No. 1 named after V.B. Borsoeva, p. Ust-Ordynsky

Kondratiev Dima, 7B class, Ust-Orda Secondary School No. 1 named after V.B. Borsoeva, p. Ust-Ordynsky

Stepanov Pasha, 7B class, Ust-Orda Secondary School No. 1 named after V.B. Borsoeva, Ust-Ordynsky settlement, e-mail:

Supervisor : Khungureeva Lyudmila Grigoryevna, teacher of physics, Ust-Ordynskaya Secondary School No. 1 named after V.B. Borsoeva, Ust-Ordynsky settlement, e - mail :

Web -address where the work is located:

Why I chose this topic:

At the beginning of the school year, listening to the story class teacher about the rest in the Summer tent eco-tourist camp Zurbagan, we learned that there is no electricity in the camp. And when the birthday of one of the vacationers came, for two days all the people baked a cake from hatamal (dried cakes) with the help of solar energy. Therefore, we chose the topic: is it possible to bake a cake faster in extreme field conditions. The main idea of ​​our topic is the construction of a solar oven, the study of its capabilities. Our stove is designed for the camp, not only for esave firewood, but also to reduce the environmental burden associated with emissions harmful products combustion.

Target:

Study of a self-made solar oven

Tasks:

Explore ways to harness the energy of the sun

Build two models of solar ovens

Explore the energy efficiency of these models

Problem

With
Today, solar energy is gaining momentum. The sun is a widely available and practically inexhaustible source of energy. In search of materials on the use of solar energy, we found out that the energy received daily from the sun's rays is more than 18 trillion kW. This is enough for all mankind, but so far there are no effective technologies for extracting this energy.

Methods

theoretical analysis and synthesis;

concretization and analogy

modeling, classification

generalization, observation

experiment

Object of study

Solar energy, electric power energy saving

Subject of study

There are two types of self-made solar ovens.

Work plan:

Collected information on this issue;

Studied the objects of study;

Released a booklet;

We made a presentation of the booklet.

Conducted research

Concluded

Research results

Everything ingenious is simple: a solar oven.

As you know, the flow of heat that the sun sends us is very large, even in middle lane in summer it easily reaches one kilowatt per square meter. A kilowatt is about the same as an electric stove burner. And it's a sin to waste so much energy. We examined the types of solar ovens, studied the design of each of them.

There are currently three types of solar oven designs:

Booklet

Cut according to the scheme from any box right size. We glue the resulting design with foil. The jar or saucepan should be black. We stuff the saucepan into a transparent plastic bag, which we tightly tie. It will keep the heat in the pot. This stove is very light and can easily be carried around.

The undoubted advantage of this oven is its compactness.

Boxed

booklet

They are a heat-insulated box, most often made of ordinary metal or wood cardboard, the top of which is covered with transparent glass. One or more reflective mirrors are often added to such a box to increase heat collection. Such heaters are mainly used for relatively slow cooking of large volumes of food.

with mirror concentrate

booklet

These plates are an ordinary concave mirror that collects rays at its focus. It is not necessary to achieve the ideal geometry of such a mirror, since the focal point is usually a very large pot.

The table shows that furnaces with mirror concentrate are very time-consuming. Therefore, we decided to make a combined panel and box.

The combined oven was easy for us: according to the scheme, a suitable size oven was cut out of cardboard. The resulting design was pasted over with foil.

In order to make a box oven with our own hands, we needed:

Plywood sheet 3mm thick.

Sheet of roofing or galvanized iron 0.5 mm thick

Beam 4x4

Boards 2cm thick, total length 4m.

Glass fixing bead

Mirror

Black paint

Two glasses 50x50 cm

Pens

Furnace manufacturing process

With the help of dads, we cut out four racks from a bar (2 rear ones are 52.6 cm and 2 front ones are 26.7 cm), on which the stove will be held with screws or nails. From plywood (1.5x1.5 m) we cut out the supporting walls of the frame, Bottom part(60.5x67.5 cm) and assembled this frame:

The next stage is the manufacture of a frame of 4 boards 6 cm wide and 54.9 cm long, which we glue together, and also fasten the rail inside the frame. In the future, we insert two glasses for thermal insulation of the furnace.

We fix the frame itself on the supporting frame, which is attached to the racks.

P
After the supporting frame is fixed, we make a special box around the perimeter, in which the main frame will be located. The main frame will be movable.

Then, with metal scissors, we cut out the metal part where the heating will take place. We make cuts on the sides, make a bend, and insert the sheet inside the future stove and fix it.

Solar oven sheet insert. We cut out the glass, which is attached to the frame with a sealant. With the help of a bar on which the loop will be attached, we install a cover on which the mirrors will be fixed with glue. Then we attach the handles.

After the first part of the study, the metal part was painted black for efficiency.

At the elective course, we learned that the principle of operation of a solar oven, like solar collector based on the greenhouse effect. The sun's rays penetrate the glass and heat up the black surface of the inside of the stove, thus heating occurs. Because the interior is airtight and the glass prevents heat from escaping, the temperature inside the oven rises until radiation and energy gain balance each other. Thus, the temperature in the furnace can reach 120-150 degrees. This is enough to cook porridge, bake a cake, boil eggs, sausages. But in winter and spring, we want to use the solar oven as a water heater.

2. An individual goal was set for each participant of the project, namely: to study the dependence of temperature in models of ice melting in different experimental dishes. During the month, the temperature was measured in solar oven models. The time of ice melting in experimental dishes was observed and recorded.

3. Conducted arithmetic mean calculations and presented the results in the form of a table and a diagram. And based on the results obtained, they proposed measures aimed at the efficient use of solar thermal energy.

Purpose of the study - where and in what dishes you can quickly boil water or bake a cake. To do this, we put ice cubes from the refrigerator into experimental dishes and recorded the temperature and time of their melting:

Timet, min

in the sun

cardboard solar oven

solar box oven

Iron

4.32

5.40

3.10

glass

22.20

15.02

7.12

ceramic

10.48

14.31

14.12

Wooden

23.20

23.20

23.45

Temperature, ° With

33

30

38

Conclusion : the solar box oven is an energy efficient design, as the table shows that the temperature is higher in it. Ice melted faster in a metal bowl. Because metal is a good conductor of heat.

We continue the research in a box oven with a black painted metal box and covered with plastic:

with a metal box and covered with plastic

Wooden stove with black painted metal box

Wooden stove with black painted metal box and covered with plastic

Iron

2.56

2.55

2.49

2.45

glass

3.16

3.16

3.12

3.11

ceramic

4.12

4.10

4.17

4.15

Wooden

6.23

7.00

7.00

6.56

Conclusion : in a wooden box oven with a black painted metal box and covered with plastic, the temperature is higher. Ice melted faster in a metal bowl.

Solar ovens undoubtedly save electrical energy, which means saving the family budget. However, we think that in order to successfully work on the problem of energy saving, not only the material and technical base, intellectual resources are needed, but also the desire to do this. And for this it is necessary to inform the population, in particular, our parents, neighbors, classmates, about the state of energy resources in our village, region, country. For this purpose, we have published a campaign booklet about solar ovens.

Nature provides us with an unpretentious way of extracting free solar energy. After all, everything ingenious is simple. Alas, we hardly ever use it. We can only hope that in the future the use of solar energy will still begin everywhere.

Resources:

Peryshkin A.V., Physics Grade 7:- M.: Bustard, 2015

Lukashik V.I., Ivanova E.V., collection of problems in physics for grades 7-9, M .: "Enlightenment", 2003

The main conclusions of the work, its purpose and application.

About 35% of all electricity in the world is used for domestic household needs. But do we need so much energy? Is it possible to use it more rationally? We thought about how much energy a person really needs for life support, and how much is wasted. After all, we have to pay for our comfort with the destruction of forests, the flooding of cities! The use of solar energy has a number of invaluable advantages:

1. Unlimited use process in time.

Unlike oil, natural gas and coal, reserves that will be depleted in

coming decades or centuries, the sun will shine for billions more years. 2.Renewability. 3.Global availability.

The sun shines on everything the globe

4. Solar ovens save money.

5.Environmental friendliness.

Saving firewood, gas and other energy sources will significantly reduce the burden on the environment associated with emissions of harmful combustion products. Their environmental friendliness is beyond doubt.

All these advantages should be the reason for the rapid growth of solar energy around the world.

Reflection.

In the course of the project, we visited the museum in Irkutsk "Baikal Ecological Wave", the center of folk art crafts, searched for material in the library, on sites on the Internet. It was very interesting to learn everything new and new in physics, to look for answers to my questions, to talk with passionate people. And there was no end of delight when they made stoves with their own hands. As for the experiments with furnaces… At first we did not believe the results, but when we were able to explain them from the point of view of physics, we felt success. We think we did very well. Problems and difficulties arose, as without them, but they were overcome.

Self-esteem :

We started working on our project in the international year of light and light technologies.We tried to achieve the goals that we set for ourselves. We are looking forward to summer. We want to conduct serious research with our models. And we really hope that our research will be useful not only to us, but to everyone who became interested in our work during the study, but also to everyone who is interested after getting acquainted with our project. And the topic of our next project will be “The use of solar panels”.

The potential of solar heat can be used not only to generate electricity at large power plants or to heat housing and utility complexes, but also in the ordinary household sphere of human activity, for example, for cooking. The very idea of ​​\u200b\u200bcreating a stove that runs exclusively on solar energy is so relevant that craftsmen have long been able to put it into practice. This article will help you make a solar oven with your own hands, without making special efforts so that you can provide yourself and your friends with a delicious hot lunch. The very forces of nature will assist you in this. It is clear that the cooking time in a solar oven will be much longer,than in a conventional oven or on an electric stove. However, such a design can be placed next to a barbecue or barbecue, thereby giving newness to your site.

For the manufacture of a solar furnace, inexpensive and commonly available materials are used:

bars;
- plywood 6-10 mm;
- roofing iron 0.5mm (galvanized);
- glass 3-4 mm;
- insulation (mineral wool).
- mirror.

First of all, we make the frame of the solar furnace from 40x40 bars and plywood. The thicker the plywood, the stronger the structure will be.

We make a glass frame that is attached to the body with hinges.

From roofing iron 0.5 mm. cut out inner part furnace (casing). At the same time, we cut the sheet according to the drawing.

After the casing is ready, with the help of nails we nail it inside the casing. Then we process the edges sandpaper so that there are no burrs.

We install the glass in the frame on a transparent silicone sealant and fix it with glazing beads.

We mount the reflective panel on the hinges.

Do not forget to attach handles for carrying the solar oven and for opening the glass door.

Carefully insulate mineral wool on the sides, between the metal casing and the body, and the bottom of the furnace. Then we sew the bottom with plywood.

We paint the metal casing with heat-resistant, black matte paint.

Glue a mirror onto the reflective panel ( mirror tiles)

The solar oven is ready to go. The first use of the solar oven, it is necessary to produce without food. Since the paint, in the early days, may give off an unpleasant odor.

Do not forget to treat the oven body with paint, antiseptic, to prevent atmospheric exposure.

The oven must be placed in direct sunlight. If the sun is low, use a reflector for maximum efficiency.

For faster cooking, use black cookware, preferably thin aluminum.

Second production method. Unfortunately, no photos.

So, to build a solar oven, we need the following materials:

1. wooden or metal box
2. a piece of dark cardboard, preferably black
3. several pieces of small, black-colored stones
4. glass according to the size of the box
5. four pieces of tin as reflectors.

Let's start with the construction of the main frame. It can be cooked from metal corners, but it is best to knock down from bars and boards. Choose the size and shape of the box to your taste, depending on the type and amount of food being cooked. It does not have to be a strictly square or rectangular stove. You can give the design any shape, such as hexagonal, round, and even elliptical. Here, perhaps, everything depends on your imagination and desire to do something unusual and original.

When the box is done, it is necessary to cover the bottom and inner walls with black cardboard or thick paper. The color of the skin must be black, as it absorbs the sun's rays more efficiently. It is necessary to fasten the paper to the box with carnations with a large hat or self-tapping screws with a washer.

Now cut the reflectors out of tin to fit the box, file all sides with sandpaper or a file to remove burrs, and attach four reflectors to the top of the box. This can be done with the help of metal or plastic corners, or simply screw the tin with screws and bend it at the required angle to the Sun. It would be more correct to install reflectors on window hinges, which can be bought on the market or at any hardware store. With the help of loops, you can easily adjust the reflectors depending on the position of the Sun in the sky.

Tin reflectors concentrate and redirect the sun's rays into wooden box, thus ensuring high-quality and fast cooking.

The last step in making a solar cooker is cutting and installing the glass, which will perform the main function of absorbing sunlight, which will be converted into heat energy to heat food. In addition, the glass is a cover for your solar oven.

Now it remains only to find on your site or elsewhere a few dark stones of medium size and put them on the bottom of the box. If you come across stones that are too light, try repainting them black and letting them dry completely. What are the stones for? They will be a kind of storage of solar heat. With their help, you can adjust the temperature in the stove, removing or, conversely, placing new stones. Hot stones will allow you to cook dinner even at a time when the Sun is not so bright and warm.

If you want to know exactly what the temperature is inside your "solar oven", don't be too lazy to install a small food thermometer, which can be purchased at any grocery store.

The heating time of the solar stove is about 20-30 minutes, depending on the time of day and the amount of solar activity.

That's it, your oven is ready. Enjoy only clean and healthy food!

And now a master class on how to make the solar battery itself.

So what is solar battery , panel (sat)? Essentially, it is a container containing an array of solar cells. Solar cells are the ones that actually do all the work of converting solar energy into electricity. Unfortunately, in order to obtain sufficient power for practical application, you need a lot of solar cells. Also, solar cells are VERY fragile. Therefore, they are united in the SB. The battery contains enough cells to produce high power and protects the cells from damage. Doesn't sound too difficult. I'm sure I can do it myself.

I started my project, as usual, by searching the net for information on homemade SBs and was shocked at how little there was. The fact that few people have made their own solar panels made me think that it must be very difficult. The idea was shelved, but I never stopped thinking about it.

After some time, I came to the following conclusions:
- the main obstacle in the construction of the SB is the acquisition of solar cells at a reasonable price
- new solar cells are very expensive and difficult to find in normal quantities for any money
- defective and damaged solar cells are available on eBay and other places much cheaper
- solar cells of the "second grade" can possibly be used to make a solar battery

When it dawned on me that I could use defective items to make my SB, I set to work. Started by buying items on eBay.

Bought several blocks of monocrystalline solar cells measuring 3x6 inches. To make a SB, it is necessary to connect 36 such elements in series. Each element generates about 0.5V. 36 cells connected in series will give us about 18V, which will be enough to charge 12V batteries. (Yes, such a high voltage is really necessary for efficient charging 12V batteries). Solar cells of this type are thin as paper, fragile and brittle like glass. They are very easy to damage.

The seller of these items dipped sets of 18 pcs. in wax for stabilization and delivery without damage. Wax is a headache when removing it. If you have the opportunity, look for items that are not covered with wax. But remember that they can get more damage in transit. Note that my elements already have wires soldered on. Look for elements with already soldered conductors. Even with such elements, you need to be prepared to do a lot of work with a soldering iron. If you buy elements without conductors, get ready to work with a soldering iron 2-3 times more. In short, it is better to overpay for already soldered wires.

I also bought a couple of sets of elements without wax filling from another seller. These items came packaged in a plastic box. They dangled in the box and chipped a little on the sides and corners. Minor chips don't really matter. They will not be able to reduce the power of the element enough to worry about it. The items I bought should be enough to assemble two SBs. I know I might break a couple while reassembling, so I bought a little more.

Solar cells are sold in a wide range of shapes and sizes. You can use larger ones or smaller ones than my 3" x 6". Just remember:
- Cells of the same type produce the same voltage regardless of their size. Therefore, to obtain a given voltage, the same number of elements will always be required.
- Larger elements can generate more current, and smaller ones, respectively, less current.
- general power of your battery is defined as its voltage multiplied by the generated current.

Using larger cells will produce more power at the same voltage, but the battery will be larger and heavier. Using smaller cells will make the battery smaller and lighter, but will not deliver the same amount of power. It is also worth noting that the use of cells in one battery different sizes- bad idea. The reason is that the maximum current generated by your battery will be limited by the current of the smallest cell, and larger cells will not work at full capacity.

The solar cells I chose are 3x6 inches and are capable of generating about 3 amps of current. I plan to connect 36 of these elements in series to get a voltage of just over 18 volts. The result should be a battery capable of delivering about 60 watts of power in bright sunlight. Doesn't sound very impressive, but it's still better than nothing. Moreover, this is 60W every day when the sun is shining. This energy will be used to charge the battery, which will be used to power lamps and small equipment just a few hours after dark. It's just that when I go to sleep, my energy needs are reduced to zero. In short, 60 watts is quite enough, especially considering that I have a wind generator that also produces energy when the wind blows.

After you buy your solar cells, store them in a safe place where they won't break, play with, or be eaten by your dog until you're ready to install them in your solar panel. The elements are very fragile. Rough handling will turn your expensive solar cells into little blue shiny and useless shards.

So, the solar battery is just a shallow box. I started by building such a box. I made it shallow so the sides don't obscure the solar cells when the sun is at an angle. Made from 3/8" plywood with 3/4" battens. The sides are glued and screwed into place. The battery will contain 36 3x6 inch cells. I decided to divide them into two groups of 18 pieces. just to make it easier to solder them in the future. Hence the central bar in the middle of the box.

Here is a small sketch showing the dimensions of my SB. All measurements are in inches (sorry, metric fans). The 3/4" thick beading goes around the entire plywood sheet. The same side goes in the center and divides the battery into two parts. In general, I decided to do so. But in general, the dimensions overall design not critical. You can freely vary everything in your sketch. I give the dimensions here for those people who constantly whine so that I include them in my sketches. I always encourage people to experiment and invent their own ideas rather than blindly follow instructions written by me (or anyone else). Perhaps you can do better.

View of one of the halves of my future battery. This half will house the first group of 18 elements. Notice the small holes in the sides. This will be the bottom of the battery (the top is at the bottom in the photo). These are ventilation holes designed to equalize the air pressure inside and outside the SB and serve to remove moisture. These holes should only be at the bottom of the battery, otherwise rain and dew will get inside. The same ventilation holes must be made in the central dividing bar.

Next, I cut out two pieces of fiberboard that fit the size. They will serve as substrates on which solar cells will be assembled. They should fit freely between the sides. It is not necessary to use exactly perforated fiberboard sheets, I just had these on hand. Any thin, rigid, and non-conductive material will do.

To protect the battery from weather troubles, we close the front side with plexiglass. These two pieces of plexiglass were cut out to cover the entire battery. I didn't have one large enough piece. Glass can also be used, but glass breaks. Hail, rocks, and flying debris can shatter glass or bounce off plexiglass. As you can see, a picture is starting to emerge of how the solar battery will look like in the end.

Oops! In the photo, two sheets of plexiglass are connected on the central partition. I drilled holes around the edge to seat the plexiglass on the screws. Be careful when drilling holes near the plexiglass edge. You will press hard - it will break, which happened to me. In the end, I just glued the broken off piece and drilled a new hole nearby.

After that, I painted all the wooden parts of the solar panel with several coats of paint to protect them from moisture and environmental influences. I painted the box inside and out. When choosing the type of paint and its color was used scientific approach. I swirled all the paint from the leftovers I had in the garage and chose the can that had enough paint to do the job.

The substrates were also painted in several layers on both sides. Make sure you paint everything well, otherwise the wood may warp from moisture. And this can damage the solar cells that will be glued to the substrates.

Now that I have the base for the SB, it's time to prepare the solar cells.

As I said before, removing wax from solar cells is a real headache. After some trial and error, I finally found a good way. But I still recommend buying items from someone who doesn't wax them.

The first step is to "dip" in hot water to melt the wax and separate the elements from each other. Do not let the water boil, otherwise the steam bubbles will strongly hit the elements one against the other. Boiling water may also be too hot, electrical contacts may be broken in the elements. I also recommend immersing the elements in cold water and then heating them slowly to avoid uneven heating. Plastic tongs and a spatula will help separate the elements once the wax has melted. Try not to pull hard on the metal conductors - they can break. I discovered this when I was trying to separate my elements. It's good that I bought them with a margin.

Here is the final version of the "installation" that I used. My friend asked what I was cooking. Imagine her surprise when I answered, "Solar cells." First " hot tub» for melting wax is in the background on the right. In the foreground on the left is hot soapy water and on the right is clean hot water. Temperatures in all pots are below the boiling point of water. First, melt the wax in a distant pan, transfer the elements one by one to soapy water to remove wax residues, and then rinse in clean water. Lay items out on a towel to dry. You can change the soapy water and rinse water more often. Just do not drain the used water into the sewer, because. the wax will harden and clog the drain. This process removed virtually all of the wax from the solar cells. Only a few left thin films, but this will not interfere with the soldering and operation of the elements. Washing with solvent will probably remove the wax residue, but it can be dangerous and smelly.

Several separated and cleaned solar cells are dried on a towel. Once separated and the protective wax removed, they became surprisingly difficult to handle and store due to their brittleness. I recommend leaving them in the wax until you are ready to install them in your Sat. This will keep you from breaking them before you can use them. Therefore, build the base for the battery first. It's time for me to install them.

I started by drawing a grid on each base to make it easier to set up each element. Then I laid out the elements on this grid reverse side up so they can be soldered together. All 18 cells for each half of the battery must be connected in series, after which both halves must also be connected in series to obtain the required voltage.

Soldering the elements together is difficult at first, but I quickly got used to it. Start with just two items. Place the connecting wires of one of them so that they cross the solder points on the back of the other. You also need to make sure that the spacing between the elements matches the markup.

I used a low power soldering iron and rosin core solder rod. Also, before soldering, I smeared the solder points on the elements with flux using a special pencil. Do not put pressure on the soldering iron! The elements are thin and fragile, press hard and break. I was sloppy a couple of times - I had to throw out a few elements.

I had to repeat soldering until a chain of 6 elements was obtained. I soldered the connecting busbars from the broken elements to the back of the last element of the chain. I made three such chains, repeating the procedure twice more. There are 18 cells in total for the first half of the battery.

Three chains of elements must be connected in series. Therefore, we rotate the middle chain by 180 degrees with respect to the other two. The orientation of the chains turned out to be correct (the elements are still lying upside down on the substrate). The next step is to glue the elements into place.

Gluing the elements will require some skill. We apply a small drop of silicone sealant in the center of each of the six elements of one chain. After that, turn the chain face up and place the elements according to the markup that was applied earlier. Lightly press down on the elements, pressing in the center to stick them to the base. Difficulties arise mainly when flipping a flexible chain of elements. A second pair of hands won't hurt.

Do not apply too much glue and do not glue the elements anywhere but the center. The elements and the substrate on which they are mounted will expand, contract, bend and deform with changes in temperature and humidity. If you glue the element over the entire area, it will break over time. Gluing only in the center allows the elements to freely deform separately from the base. The elements and the base can be deformed in different ways and the elements will not break.

Here is the fully assembled half of the battery. I used a copper braid from a cable to connect the first and second chain of elements.

You can use special tires or even ordinary wires. I just had a copper braid from the cable at hand. We make the same connection with reverse side between the second and third chain of elements. With a drop of sealant, I attached the wire to the base so that it would not “walk” or bend.

Test the first half of the solar battery in the sun. With a weak sun in a haze, this half generates 9.31V. Hooray! Works! Now I need to make another half of the same battery.

After both bases with elements are ready, I can place them in place in the prepared box and connect.

Each of the halves is placed in its place. I used 4 small screws to secure the base with the cells inside the battery.

I passed the wire for connecting the halves of the battery through one of the ventilation holes in the central side. Here, too, a couple of drops of sealant will help secure the wire in one place and prevent it from dangling inside the battery.

Each the solar panel in the system must be provided with a blocking diode connected in series with the battery. The diode is needed to prevent the discharge of batteries through the battery at night and in cloudy weather. I used a 3.3A Schottky diode. Schottky diodes have a much lower voltage drop than conventional diodes. Accordingly, there will be less power loss on the diode. I bought a set of 25 31DQ03 diodes on eBay for just a couple of bucks. I will still have a lot of diodes for my future SBs.

At first I planned to attach a diode outside the battery. But after looking specifications diodes, I decided to put them inside the battery. For these diodes, the voltage drop decreases with increasing temperature. There will be a high temperature inside my battery, the diode will work more efficiently. We use some more silicone sealant to secure the diode.

I drilled a hole in the bottom of the battery near the top to get the wires out. The wires are tied into a knot to prevent them from being pulled out of the battery, and secured with the same sealant.

It is important to let the sealant dry before we put the plexiglass in place. I recommend based on previous experience. Vapors from silicone can form a film on the inside surfaces of plexiglass and elements if you do not allow the silicone to air dry.

And some more sealant to seal the outlet.

I screwed a two-pin connector onto the output wire. The socket of this connector will be connected to the battery charge controller that I use for my wind turbine. Thus, the solar battery will be able to work with it in parallel.

This is what the finished SB looks like with the Plexiglas screen screwed on. Plexiglas is not sealed yet. At first I did not seal the joints. Did a little testing first. According to the results of the tests, I needed access to the insides of the battery, a problem was discovered there. I lost contact on one of the elements. Maybe this happened due to a temperature difference or due to careless handling of the battery. Who knows? I disassembled the battery and replaced this damaged element. Since then there have been no problems. In the future, I may seal the joints under the plexiglass with sealant or cover them with an aluminum frame.

Here are the voltage test results of the completed battery in the bright winter sun. The voltmeter shows 18.88V with no load. This is exactly as I expected.

And here is the current test under the same conditions (bright winter sun). Ammeter shows 3.05A - current short circuit. This is just close to the calculated current of the elements. The solar panel works great!

Solar battery at work. I move it around a couple of times a day to keep it aligned with the sun, but it's not that big of a deal. Perhaps someday I will build an automatic system for tracking the sun.

Using the free energy of the sun is very tempting. Freebie - she always beckons.

I already wrote about, and this article is about how to cook food using light from the sun.

First, about a homemade solar oven.

Making a solar oven with your own hands is very simple, you just need to concentrate the incident light at one point and you're done.

Here is a simple way to concentrate - use film and water.

On such an installation, you can melt metal and cook food.

The installation is stationary and is suitable for a country house or cottage. Well, or a shelter located so that electricity cannot be supplied to it.

It is the latter condition - the inaccessibility of electricity most often becomes the reason for the manufacture of a solar furnace. The sun doesn't shine every day, of course. sufficient, but saving gas or gasoline on clear days while cooking is a very good idea.

A portable solar concentrator is easy to make from a mirror film.

The main thing to give the mirror layer a concavity is to glue the central part to the bottom, before fixing the edges of the mirror film.

How to make a solar oven with your own hands

This video shows the drawings of a solar oven and the theory of its operation.

And here is the continuation - step by step manufacturing solar oven.

Demonstration of the solar oven.

As you can see, the solar oven is very simple to manufacture and works even in winter, unless, of course, the day is sunny.

However, you can’t take such structures on a hike, and sometimes, especially if you travel in winter in the steppe or mountainous areas, you have to carry fuel with you. In such trips, a portable solar oven is very appropriate.

Here finished example a portable solar stove in the form of a pipe that runs exclusively on solar energy - not a drop of fuel is used to cook barbecue and other yummy.

Where to buy a solar oven

Camping Solar Oven Portable
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July 10th, 2017

In fact, there are several such structures in the world. Let's start with Solar Furnace in France, i.e. from France.

The Solar Furnace in France is designed to generate and concentrate the high temperatures needed for various processes.

This is done by capturing the sun's rays and concentrating their energy in one place. The structure is covered with curved mirrors, their radiance is so great that it is impossible to look at them, to the point of pain in the eyes. In 1970, this structure was erected, the Eastern Pyrenees were chosen as the most suitable place. And up today The furnace remains the largest in the world.

The array of mirrors is entrusted with the functions of a parabolic reflector, and a high temperature regime in the focus can reach up to 3500 degrees. Moreover, you can regulate the temperature by changing the angles of the mirrors.

The Solar Furnace, using the natural resource of sunlight, is considered an indispensable way to obtain high temperatures. And they, in turn, are used for various processes. So, the production of hydrogen requires a temperature of 1400 degrees. Test modes of materials, carried out in high-temperature conditions, provide for a temperature of 2500 degrees. So tested spacecraft and nuclear reactors.

So the Solar Furnace is not only an amazing building, but also a vital and efficient one, while it is considered an environmentally friendly and relatively cheap way to get high temperatures.

The array of mirrors acts as a parabolic reflector. The light is focused in one center. And the temperature there can reach temperatures at which steel can be melted.

But the temperature can be adjusted by setting the mirrors at different angles.

For example, temperatures around 1400 degrees are used to produce hydrogen. Temperature 2500 degrees - for testing materials in extreme conditions. For example, this is how nuclear reactors and spacecraft are tested. But temperatures up to 3500 degrees are used for the manufacture of nanomaterials.

The Solar Furnace is an inexpensive, efficient and environmentally friendly way to produce high temperatures.

In the south-west of France, grapes take root remarkably and all kinds of fruits ripen - it's hot! Among other things, the sun shines here almost 300 days a year, and in terms of the number of clear days, these places are perhaps second only to the Côte d'Azur. If we characterize the valley near Odeio from the point of view of physics, then the power of light radiation here is 800 watts per 1 square meter. Eight powerful incandescent bulbs. A little? It is enough for a piece of basalt to spread into a puddle!

- The solar oven in Odeyo has a capacity of 1 megawatt, and this requires almost 3 thousand meters of mirror surface, says Serge Chauvin, curator of the local solar museum. — And to collect light from such large surface you need a focal point with a diameter of a dinner plate.

Opposite the parabolic mirror, heliostats are installed - special mirror plates. There are 63 of them with 180 sections. Each heliostat has its own "point of responsibility" - the sector of the parabola, on which the collected light is reflected. Already on a concave mirror, the rays of the sun are going to a focal point - that same stove. Depending on the intensity of the radiation (read - the clarity of the sky, time of day and season), temperatures can be very different. In theory - up to 3800 degrees Celsius, in reality it went up to 3600.

- Together with the movement of the sun, heliostats also move across the sky, Serge Chauvin begins his tour. — Each has an engine installed at the back, and all together they are centrally controlled. It is not necessary to install them in an ideal position - depending on the tasks of the laboratory, the degree at the focal point can vary.

The solar oven in Odeyo began to be built in the early 60s, and was put into operation in the 70s. For a long time it remained the only one of its kind on the planet, but in 1987 a copy was erected near Tashkent. Serge Chauvin smiles: "Yes, yes, exactly a copy."

The Soviet stove, by the way, also remains operational. True, not only experiments are carried out on it, but also some practical tasks are performed. True, the location of the furnace does not allow reaching the same high temperatures as in France - at the focal point, Uzbek scientists manage to get less than 3000 degrees.

The parabolic mirror consists of 9000 plates - facets. Each of them is polished, has an aluminum coating and is slightly concave for better focusing. After the furnace building was built, all bevels were installed and manually calibrated - it took three years!

Serge Chauvin leads us to a site near the kiln building. Together with us - a group of tourists who arrived in Odeyo by bus - the flow of lovers of scientific exoticism does not dry out. The museum curator was about to demonstrate the hidden potential of solar energy.

Madame and Monsieur, your attention!- Serge, although he looks more like a scientist, is more like an actor. — The light emitted by our star makes it possible to instantly heat materials, ignite and melt them.

A solar oven worker picks up an ordinary branch and places it in a large vat with a mirrored interior. It takes Serge Chauvin a few seconds to find a focus point, and the stick instantly flares up. Wonders!

While the French grandparents are gasping and groaning, the museum worker moves to a free-standing heliostat and moves it exactly so that the reflected rays hit a small copy of the parabolic mirror installed right there. This is another illustrative experiment showing the possibilities of the sun.

— Madame and Monsieur, now we will melt the metal!

Serge Chauvin sets a piece of iron in the holder, moves the vise in search of a focus point and, having found it, moves away a short distance.

The sun is doing its job.

A piece of iron instantly heats up, begins to smoke and even spark, succumbing to hot rays. Literally in 10-15 seconds, a hole the size of a coin of 10 euro cents is burned in it.

— Voila! Serge exults.

While we are returning to the museum building, and the French tourists are seated in the cinema hall to watch a scientific film about the work of the solar furnace and laboratory, the caretaker tells us some interesting things.

- Most often, people ask why all this is necessary, Serge Chauvin throws up his hands. — From the point of view of science, the possibilities of solar energy have been studied, applied where possible in everyday life. But there are tasks that, due to their scale and complexity of execution, require installations like this one. For example, how do we model the effect of the sun on the skin spaceship? Or the heating of the descent capsule returning from orbit to Earth?

In a special refractory container, installed at the focal point of the solar furnace, it is possible to recreate such, without exaggeration, unearthly conditions. It has been calculated, for example, that a skin element must withstand temperatures of 2500 degrees Celsius - and this can be tested empirically here in Odeyo.

The caretaker leads us through the museum, where various exhibits are installed - participants in numerous experiments carried out in the oven. Our attention is drawn to the carbon brake disc…

- Oh, this thing is from the wheel of a Formula 1 car, Serge nods. — Its heating under certain conditions is comparable to what we can reproduce in the laboratory.

As mentioned above, the temperature at the focal point can be controlled using heliostats. Depending on the experiments carried out, it varies from 1400 to 3500 degrees. lower limit needed for hydrogen production in the laboratory, range from 2200 to 3000 - for testing various materials under extreme heat conditions. Finally, above 3000 is the area of ​​work with nanomaterials, ceramics and the creation of new materials.

— The furnace in Odeyo does not perform practical tasks, Serge Chauvin continues. — Unlike our Uzbek colleagues, we do not depend on our own economic activity and we do science only. Among our customers are not only scientists, but also a variety of departments, such as defense.

We are just stopping at a ceramic capsule, which turns out to be the hull of a drone ship.

“The War Department built a smaller diameter solar oven for their own practical needs here in the valley near Odeyo, Serge says. — It can be seen from some sections of the mountain road. But for scientific experiments they still contact us.

The caretaker explains the advantage of solar energy over any other in the course of scientific tasks.

- First, the sun shines for free, He curls his fingers. — Secondly, mountain air contributes to conducting experiments in a "pure" form - without impurities. Thirdly, sunlight allows materials to be heated much faster than any other apparatus, which is extremely important for some experiments.

It is curious that the furnace can work practically all year round. According to Serge Chauvin, the best month for experiments is April.

- But if necessary, the sun will melt a piece of metal for tourists even in January, the caretaker smiles. — The main thing is that the sky is clear and cloudless.

One of undeniable advantages The very existence of this unique laboratory is its complete openness to tourists. Up to 80 thousand people come here every year, and this does much more to popularize science among adults and children than a school or university.

Font-Romeu-Odeillo is a typical French pastoral town. Its main difference from thousands of the same is the coexistence of the sacrament household life and science. Against the background of a 54-meter mirror parabola - mountain dairy cows. And constant hot sun.

Now let's move on to another building.

Forty-five kilometers from Tashkent, in the Parkent district, in the foothills of the Tien Shan, at an altitude of 1050 meters above sea level, there is a unique structure - the so-called Big Solar Furnace (BSP) with a capacity of a thousand kilowatts. It is located on the territory of the Institute of Materials Science NPO "Physics-Sun" of the Academy of Sciences of the Republic of Uzbekistan. There are only two such furnaces in the world, the second is in France.

The BSP was put into operation back in the Soviet Union in 1987,” says the scientific secretary of the Institute of Materials Science of the NPO “Physics-Sun”, Candidate of Technical Sciences Mirzasultan Mamatkasymov. “Sufficient funds are allocated from the state budget to preserve this unique object. Two laboratories of the institute are located here, four - in Tashkent, where the main scientific base is located, on which the study of chemical and physical properties new materials. We are in the process of synthesizing them. We experiment with these materials by observing the melting process at different temperatures.

BSP is a complex optical-mechanical complex with automatic control systems. The complex consists of a heliostat field located on a mountainside and directing the sun's rays into a paraboloid concentrator, which is a giant concave mirror. At the focus of this mirror, the highest temperature is created - 3000 degrees Celsius!

The heliostat field consists of sixty-two heliostats arranged in a checkerboard pattern. They provide the mirror surface of the concentrator with a light flux in the mode of continuous tracking of the Sun throughout the day. Each heliostat, measuring seven and a half by six and a half meters, consists of 195 flat mirror elements called "facets". The reflecting area of ​​the heliostat field is 3022 square meters.

The concentrator, on which the heliostats direct the sun's rays, is a cyclopean structure forty-five meters high and fifty-four meters wide.

It should be noted that the advantage of solar furnaces, compared with other types of furnaces, is the instantaneous achievement of a high temperature, which makes it possible to obtain clean materials without impurities (also thanks to the purity of the mountain air). They are used for oil and gas, textile and a number of other industries.

Mirrors have certain period operation and sooner or later fail. In our workshops, we manufacture new mirrors that we install to replace the old ones. There are 10700 of them only in the concentrator, and 12090 in heliostats. The process of making mirrors takes place in vacuum plants where aluminum is sprayed onto the surface of the spent mirrors.

Ferghana.Ru:- How do you solve the problem of finding specialists, because after the collapse of the Union, there was an outflow of them abroad?

Mirzasultan Mamatkasymov:- At the time of the launch of the installation in 1987, specialists from Russia and Ukraine worked here, who trained ours. Thanks to our experience, we now have the opportunity to train specialists in this field on our own. Young people come to us from the Faculty of Physics of the National University of Uzbekistan. I myself have been working here since 1991 after graduating from university.

Ferghana.Ru:- When you look at this grandiose structure, at the openwork metal constructions, as if floating in the air and at the same time supporting the "armor" of the concentrator, frames of science fiction films pop up in my memory ...

Mirzasultan Mamatkasymov:- Well, in my lifetime no one has tried to shoot science fiction using these unique "settings". True, Uzbek pop stars came to shoot their videos.

Mirzasultan Mamatkasymov:- Today we will melt briquettes pressed from powdered aluminum oxide, the melting point of which is 2500 degrees Celsius. During the melting process, the material flows down an inclined plane and drips into a special pan, where granules are formed. They are sent to a ceramic workshop located near the BSP, where they are crushed and used to make various ceramic products, ranging from small thread guides for the textile industry to hollow ceramic balls that look like billiard balls. Balls are used in the oil and gas industry as floats. At the same time, evaporation from the surface of oil products stored in large containers at oil depots is reduced by 15-20 percent. Behind last years we have made about six hundred thousand of these floats.

We manufacture insulators and other products for the electrical industry. They are characterized by increased wear resistance and strength. In addition to aluminum oxide, we also use a more refractory material - zirconium oxide with a melting point of 2700 degrees Celsius.

The melting process is controlled by the so-called "vision system", which is equipped with two special television cameras. One of them directly transmits the image to a separate monitor, the other - to a computer. The system allows both to observe the melting process and to carry out various measurements.

It should be added that the BSP is also used as a universal astrophysical instrument that opens up the possibility of conducting studies of the starry sky at night.

In addition to the above works, the institute pays great attention to the manufacture of medical equipment based on functional ceramics (sterilizers), abrasive instruments, dryers, and much more. Such equipment has been successfully implemented in medical institutions our republic, as well as to similar institutions in Malaysia, Germany, Georgia and Russia.

In parallel, solar installations were developed at the Institute low power. So, for example, scientists of the institute created solar furnaces with a capacity of one and a half kilowatts, which were installed on the territory of the Tabbin Institute of Metallurgy (Egypt) and at the International Metallurgical Center in Hyderabad (India).

Scientists have long found a way to use solar energy to power various devices or even residential facilities. On the shelves of stores there are many different equipment that runs on solar panels. But not everything must be purchased for money, since some units can be assembled at home from improvised materials. This is a solar oven.

Solar ovens have long been available in stores or online. They are equipped with many useful gadgets making it easier to operate the equipment.

The solar oven is light, it can be folded like a suitcase in a few minutes and also quickly expanded into working position is the perfect travel tool.

Furnaces made in industrial scale, combine all the positive properties of solar parabolic-cylindrical concentrators, as well as vacuum tubes. Thanks to this, the heating temperature reaches 300 degrees Celsius.

To control the temperature, a thermometer is also built into the equipment - this is an integral part of the control unit.

Also, a thermostat with a specific setting is mounted in the oven. operating temperature, as well as a system for turning mirrors.

AT modern device set a timer, which, after a certain time, will begin to close the mirrors inside the solar oven. When the set time arrives, the timer will also beep to let you know that the dish is ready.

The electronic part of the equipment is powered by solar energy through a battery installed in the housing.

When assembled, the suitcase has the following dimensions:

• length 75 cm;
• height 40 cm;
• thickness - 11 cm.

The weight is quite small and comfortable for carrying over a long distance - only 4 kg.

Using the oven, you can cook vegetables, mushrooms, meat or even bake pies. The main advantage is environmental friendliness and saving on electricity. The equipment does not pollute the environment at all.

Varieties of solar ovens

Modern devices are available in three main varieties:

1. Boxed.
2. With mirror concentrator.
3. Combined.

box oven

The equipment is a heat-insulated box covered with mirror material or plastic. To increase the collection of heat, several mirrors are added inside, which serve as reflectors.

This type of equipment is used for slow cooking. Since at self-manufacturing the box can be of any size, then large volumes of food can be cooked on it. Store samples are not large.

Furnace with concentrator

The device is a concave mirror that collects the sun's rays in its focus and redirects it to a point set by the user. When making it yourself, there is no need to observe the ideal geometry of the mirror, since the focus will be on a large pot or other container with food.

A feature of the structure is the achievement of a high heating temperature. The equipment is convenient to use when you need to warm up a small amount of food.

But the stove also has a design flaw: it is necessary to constantly monitor the rays of the sun and from time to time turn the mirror, redirecting the beam in the required direction. If you do not skillfully handle the oven, you can burn your hands and eyes. But by following safety precautions, this trouble can be avoided.

Combined

The combined type is a combination of the two previous options. A pot with food to be heated is placed in a box, which is framed on one side by a concave plate with mirror surface. The furnace quickly develops and gathers in working position.

DIY step-by-step instructions for making a solar oven

Assembling a solar oven with your own hands is not difficult. Can be used different methods based on drawings which are very simple and intuitive.

Users may have questions about the dimensions of the ovens. It is advisable to rely on the following tips:

1. If you need to make a stove for a summer residence, or a country house, then you need to think about the need for a more solid and fixed structure.
2. If the device is needed for a hike, then the design should be collapsible and as light as possible - for ease of transportation.
3. If the furnace is planned to be moved by car, then the design can be made more complex, but it must still be collapsible.

The simplest option for a solar oven is to use an ordinary umbrella. For manufacturing, there is no need to use drawings, since the device is as simple and understandable as possible.

A mirror film or aluminum foil is glued to the open umbrella from the inside. The handle must be detached so that it does not interfere when placed in the center of the warming dish. This is all the necessary work. The oven is completely ready for use.

Now you need to stick a stand into the ground, where the pot and teapot will be attached, and place an impromptu mirror near the objects and focus the sun's beam on the container with food.

Some masters use broken mirror and the inside of the umbrella is covered with a kind of mosaic. But the design in this case is heavy, and not collapsible.

boxed

When assembling a box structure, several main factors must be considered:

1. The walls located on the inside of the box are covered with foil, and should have a very good reflection.
2. The pan that fits inside must absorb the sun's rays, and therefore it is advisable to paint it black or smoke it.
3. Thermal insulation must be at a high level. The walls of the box should fit snugly against each other so that the heat does not go out. To implement high-quality thermal insulation, ordinary cardboard or other natural materials are used that will not emit harmful substances when heated. After assembly, the temperature inside the oven can reach 170 degrees Celsius. But at the same time, you should not be afraid of the fire of the box, since this temperature will not be enough.

If you approach the construction of the structure with all responsibility, then the furnace will last up to 10 years or longer.

Non-separable unit:

1. A reliable box is knocked down from the boards.
2. Black paper (compacted) is placed inside over the entire area. This is necessary so that the energy of the sun is absorbed by the device as much as possible.
3. Based on the dimensions of the received box, reflectors are cut out of tin. The edges before installation should be rounded and sanded to avoid cuts.
4. Reflectors are fixed on top of the box. Ordinary hinges or screws are used - at the discretion of the master. After the sheets are bent under right angle to accumulate the sun's rays on a specific object inside the unit.
5. The lid must be glass. Thus, ultra-violet rays converted into heat energy needed to heat food.
6. Under the stove, it is desirable to build a small platform of bricks. They will accumulate the received heat.
7. If you want to monitor the temperature, you should attach a thermometer to the box.

This type of solar oven is ideal for country conditions. It will not be possible to take it with you on a trip due to the relatively large weight, dimensions and inseparability.

Mirror with reflector

To make a mirror oven with a reflector, you can use the umbrella option that was presented above, or assemble the structure according to the drawing.

1. You will need to cut the petals out of cardboard in the amount of 12 pieces.
2. After all the parts are connected along the long side.
3. Next, the inner part of the resulting "plate" is fastened.
4. All parts are pulled together with wire or a good rope at the base.
5. The plate is covered with foil, which reflects the sun's rays well.

Combination oven

The combined type is the easiest to manufacture, and is a concentrator, which is made from several flat mirrors. You will also need a pan with good thermal insulation.

To isolate the internal object, ordinary plastic bags are used.

As a mirror, you can use thick cardboard, to which aluminum foil is glued.

The design is remarkable in that it can be folded and carried. Approximate dimensions are 33 by 33 cm. But larger sizes can also be assembled if desired.

Assembly process:

1. First you need to prepare the basis for the body. It is advisable to use a sheet of plywood. An aluminum or steel rod is placed in the center and securely fastened. Length - half a meter. A thread is preliminarily made on the rod in order to place a stand on it in the future.
2. Grooves are made in which stiffeners made of plywood are placed.
3. The walls are assembled from the same plywood. You will need four rectangular sheets. On the one hand, they should be cut out with a curved arc, and grooves should be made with the arc for fastening to the ribs.
4. The parts to be joined are covered with glue and connected. For additional fixation, it is desirable to use paper clips. After the box has dried, shake the blanks, gently pull the walls to make sure they are reliable. If the design has passed the test, you can proceed to the next step. But in case some part dangles, then it will need to be put in place, poured with glue again.

After creating the box, you can move on to the mirror.

1. You need a triangular thick cardboard with a smooth texture.
2. All cardboard parts are overlapped and on top of the attached ribs.
3. After fixing, the cardboard is covered with a layer of glue. After that, aluminum foil is applied.
4. A stand is placed on the rod at a point equal to half the radius of the mirror surface.

The DIY solar oven is ready for use. Aluminum is also used instead of wood for the box. It conducts heat well and does not corrode.

The instructions will answer the question of how to make a solar oven at home.

Advantages and disadvantages

Self-assembled solar ovens are varied in size, but identical in structure, and therefore there are no difficulties with assembly. With the help of stoves, you can easily accumulate heat to heat food. The principle of operation is based on absorbing the energy of sunlight and redirecting them to the desired object.

Solar ovens have the following advantages:

1. Cheapness. For work it is not necessary to buy fuel and use additional energy sources. It only needs sunlight to work.
2. Food is prepared as safely as possible - do not be afraid of fire, as when making a fire.
3. The stove is easy to care for and easy to operate - you just need to direct the sun's beam to the desired object through the mirror surface.
4. Mobility. The stove is quickly assembled and disassembled. Therefore, there are no problems with transportation.
5. Environmental friendliness.
6. Food is heated evenly and there is no risk of burning. The food does not need to be stirred.

These qualities have provided solar ovens with great popularity among travelers. The oven is easy to cook food. For cooking, you only need to direct the sun's ray to the desired object.

Comparative characteristics of the thermal power of the oven and the cooking time