Solar concentrators. Home heating with a DIY solar collector DIY solar water heating concentrator

written after reading an article in Photon International 12/2012. All photos and data are from this source.

Briefly:
1) The capacity of CSP (Concentrated Solar Power) stations around the world increased by 1 GW in 2012. This market is growing by >100% every year (not a typo!).
2) Installed capacity: 2.8 GW, 2.9 under construction, 7 GW planned.
3) The most popular is the technology of parabolic reflectors, but concentrators-towers and concentrators on Fresnel lenses are gaining strength.

Now more. The market is growing like this:


(in light brown and brown: annual installed and installed capacity (GW) of CSP. Source: Photon International 12/2012)

How will CSP technologies develop? Let's look at this picture:


(explanation of the "legend" from left to right: general, parabolic reflectors, towers, parabolic dishes, linear Fresnel reflectors. The first diagram - at the end of 2012, the second: under construction, the last: planned)

It is obvious that parabolic reflectors are "today", but concentrator towers will be popular "tomorrow". The largest project under construction in this area to date is the 392 MW Ivanpah Solar Electric Generating Station in southern California. 170,000 mirrors will focus the light onto the towers.

CLFRs are gradually winning back the market: there is an increase from 1 to 7%. The largest project in this area is a 100 MW project in Rajasthan from Avera Solar.

What are parabolic reflectors?

This is a system where parabolic mirrors, turning along their axis, focus the sun's rays on a heat-absorbing tube. Such a system allows you to concentrate 100 times and heat the heat carrier (special oil) up to 400 degrees. Through the heat exchanger, the hot oil gives off energy to the steam, which, in turn, rotates the turbine. New systems in this area may include a battery in the form of a molten salt tank (up to 8 hours). The system is already well known (since the 80s).

Disadvantages and advantages:

1. proven technology.


2. But, high costs relative to other, "green" sources (eg PV).


3. But, the low temperature of the coolant.


4. But, in some cases, such systems require the provision of water, which is not easy in a desert environment.


5. But, the installation site should not have a slope of more than 1%.

What are concentrators - towers?
This is a system where often thousands of rotating mirrors track the sun and focus the energy onto a power receiver. You can concentrate energy 1000 times. Tower height from 5 to 165 m. Mirrors from 1.1 to 120 sqm. Temperature from 440 to 550 degrees Celsius. Water or molten salt is used to transfer heat.

Disadvantages and advantages:

1. They allow to achieve higher temperatures, higher efficiency, lower energy cost than parabolic reflectors.


2. Does not require ultra flat terrains (can be set at 5% gradient).


3. The energy reserve in the tank with molten salt is up to 15 hours.


4. But, the history of using such systems is shorter and therefore the risk of lending is higher.


5. But, the price is still high.

What are concentrator systems with linear Fresnel reflectors?
These are simpler systems compared to parabolic channels. Light is concentrated 30 times, and instead of oil, water is used for heat transfer.

Disadvantages and advantages:
Simple design, low energy cost.
But, high technological risk: the technology has not yet been tested as parabolic reflectors.

Today, concentrators are fighting for their existence: solar panels that are becoming cheaper and already familiar are putting pressure on this market.

• 1 installed watt from concentrators today costs about $5 (parabolic concentrators),


• 1 installed watt for concentrator towers is about $7 (the price remains the same if the energy is stored in the sand for 6-7 hours, $10 if the reserve is for 12-15 hours).


• 1 installed watt for conventional panels is about $1.

Generation of 1 kWh will cost 14-35 cents. According to the goal of the US Department of Energy, in 2020 the cost of el. energy from hubs in southern California should be 6 cents.

However, do not forget that this is a much younger industry that follows the path of traditional photovoltaics made 10 years ago. There is a potential for price reduction in this area, and I am sure that there will be enough "place in the sun" for all technologies.

But I also remember the optimism with which Siemens took up concentrators (Siemens recently announced the end of work in this area) and I remember the enthusiasm for thin-film silicon photovoltaics. In both cases, the window of opportunity closed with a bang for many pockets.

Let's talk about the disadvantages. Mirrors need to be cleaned. Moreover, their surface must be perfect and must remain so. all the time station operation.


(cleaning

The total amount of solar energy that reaches the Earth's surface in just a week exceeds the energy reserves of oil, uranium, coal and gas worldwide. There are many ways to save solar heat. One such solution is solar concentrators. This is a special device for collecting solar energy, which performs the function of heating the heat-transfer material. Usually used for space heating and hot water needs. It is in this property that it differs from solar panels, which directly produce electricity.

Device

The main function of a solar concentrator is to focus solar radiation on the emitter receiver, which is located on the focal line or focal point of the solar energy collector.

The device of the solar concentrator assumes the presence of the following elements:

• Lenses or reflectors that are used as a concentrator of sunlight.
• Base structure on which lenses or reflectors are mounted.
• A heat-receiving element, which often acts as a solar collector.
• Pipelines that supply and discharge coolant.
• Tracking system drive mechanism. This mechanism in most cases includes:
  - Electronic signal conversion unit.
  — Sun direction sensor.
  – An electric motor with a gearbox that rotates the structure of the solar concentrator in two planes.

Depending on the design, the device may also include Fresnel lenses, a thermometer, a control valve, a heating circuit, a circulation pump, and a number of other elements.

Operating principle

The principle of operation of solar concentrators lies in the focusing of the sun's rays on a container with a coolant.

The work of the coolant is to absorb solar energy. Depending on the method used to concentrate solar energy, the following can be used:

• Parabolic trough concentrators that focus solar radiation on oil or water pipes
• Heliocentric towers.
• Special parabolic mirrors.

Solar radiation in certain models of concentrators can be concentrated:

• At the focal point.
• Along the focal line where the receiver is located.

Everything looks like this:

• Achieving high temperatures in concentrators is ensured by reflecting solar radiation from a larger surface onto a smaller surface of the receiver-absorber.
• The heat-carrier fluid that passes through the receiver absorbs heat as much as possible and transfers it to the consumer.

The temperature in the receiver reaches high values, but the concentrators are able to focus only direct solar radiation. As a result, their effectiveness in cloudy or foggy weather is significantly reduced. The highest efficiency indicators are shown in regions with a high degree of insolation, for example, in equatorial or desert regions.

In order to use solar radiation as efficiently as possible, it is necessary to ensure that the solar concentrators are oriented in the direction of the sun. For this purpose, the hubs are equipped with a tracker, that is, a special tracking system. It turns the system directly "face" to the sun.

Single-axis servo systems rotate the system from east to west. In turn biaxial systems from north to south, to orient the system to the Sun all year round.

On an industrial scale, a parabolic-cylindrical mirror concentrator provides focusing of solar radiation, providing more than a hundredfold of its concentration. As a result, the liquid heats up to almost 400 degrees. Passing through a series of heat exchangers, the liquid generates steam, which rotates the turbine of the steam generator. To minimize heat loss, the receiving tube is surrounded by a transparent glass tube that extends along the focal line of the cylinder.

Kinds

According to the constructive scheme of work, concentrators are divided into the following varieties:

• Parabolic solar concentrators.

• Parabolic trough concentrators.

• Solar towers.

• Concentrators on spherical lenses.

• Concentrators on Fresnel lenses, that is, flat lenses.

Solar concentrators are also classified into the following types:

• Strongly concentrating (Ks≥100) and weakly concentrating (Ks<100). Это зависит от уровня повышения плотности излучения, либо степени его концентрации.
• Selective and non-selective systems, that is, according to the degree of influence of concentrated radiation on spectral characteristics.
• Refractive (lens) and reflective (mirror) systems - according to the nature of the interaction of sunlight with
  optical elements of solar concentrators.
• Without tracking, equatorial, azimuth-zenithal system - according to the sun tracking scheme.
• Single- and multi-element systems - according to the number of optical elements that sequentially participate in the process of radiation concentration.
• With a tracking receiver, with a tracking reflector - according to the method of tracking the sun.
• liquid or air-convective heat removal - according to the heat removal method.

Peculiarities

• The radiation of the sun in some concentrators is focused at the focal point, in others - along the focal line, where the receiver is located. When radiation is reflected from a larger surface to a smaller one, a high temperature of the receiver is reached, this heat is removed by the coolant.
• The efficiency of concentrators is significantly reduced during cloudy periods, since only direct solar radiation is focused. In this regard, such systems have a high efficiency in regions where the level of insolation is especially high: in the equatorial region and deserts. To improve the efficiency of the application of solar radiation, concentrators are often equipped with tracking systems that provide accurate orientation to the sun.
• Since the cost of solar concentrators is quite high, and tracking systems need periodic maintenance, in most cases their use is limited to industrial power generation systems. In addition, such installations can be used in hybrid systems, for example, in conjunction with hydrocarbon fuels. In this case, the storage system will reduce the cost of electricity produced.

Application

• Parabolic-cylindrical solar concentrators and towers work optimally in the structure of large systems connected to a network of power plants with a capacity of 30-200 MW.
• Disk-type systems are made of modules and can be used in stand-alone installations and groups with a total power of several megawatts.

Parabolic trough solar concentrators are currently one of the most advanced solar energy technologies. Most likely, they will be used in industry in the near future. Thanks to their efficient heat storage capacity, tower-type stations can also become stations of the near future. Due to the modular nature of the "trays", they can be used in small installations.

"Plates" and towers make it possible to provide higher efficiency values ​​while obtaining energy at a lower cost. However, this requires a significant reduction in capital costs. Currently, only parabolic concentrators have already been tested and will soon be improved. Tower solar concentrators require the demonstration of operational reliability and efficiency. For poppet-type systems, the development of an inexpensive concentrator and the creation of a commercial engine are needed.

Parabolic concentrators

Benefits - Proven technology.

Disadvantages:

• High costs.
• Low coolant temperature.
• We need an ultra-flat landscape.

towers

Advantages:

• Higher efficiency.
• higher temperature.
• Lower cost of energy.
• You don't need an ultra-flat landscape.

Disadvantages:

• High price.
• Low prevalence.

Solar concentrators with linear Fresnel reflectors

Advantages:

• Low energy cost.
• Simple design.

Ever since the beginning of our millennium, the possibility and methods of using the energy of the sun's rays have been concerned about the most outstanding minds of mankind. Even then, people perfectly understood that the celestial body named the Sun is a source of radiation of inexhaustible energy. However, no one figured out how to "tame" and use it to their advantage at that distant time. According to sources that have survived to this day, the writers of antiquity, Plutarch and Polybius, indicated that the person who first wrote the drawings with his own hand and assembled a working invention was Archimedes.

It was a device that, by means of some devices based on optics, concentrated the radiation of solar radiation into one powerful stream. Subsequently, the invention was used to destroy the imperial fleet of the Romans, who arrived with predatory goals.

At its core, the invention of a wise Greek engineer, which he assembled with his own hands, is the first parabolic concentrator based on solar energy created on planet Earth, the principle of which was to concentrate radiation in one small beam.

In the area affected by such a beam, the temperature level could reach from 300 to 400 degrees Celsius. Such energy, concentrated on the hull of any of the ships of the Roman navy (which at that time consisted entirely of wood), would have been enough to ignite a sea vessel. Today, one can only make assumptions about what specific invention Archimedes gave the world, but based on modern knowledge and ideas about technologies and achievements in this field of energy, there were only two possible options.

Let's start with the fact that the very name that the invention received is a solar concentrator, this name speaks for itself.

A lens convex on both sides is an example of a simple concentrator.

This is a device that, by capturing solar radiation by a certain bending of the surface, concentrates the rays at one point, achieving multiple indicators of an increase in energy. We all remember from our young past an ordinary lens, convex on both sides - this is an example of the simplest concentrator. In sunny weather, by adjusting the angle of incidence of the sun's radiation with one's own hands, it was possible to burn everything that came to mind, any figure or inscription, on a wooden surface or on paper.

Such a lens belongs to the group of refractor concentrators. In addition to convex lenses, Fresnel lenses, which are a prism, also belong to the same group of concentrators. Long focus concentrators are assembled using so-called linear lenses. Such hubs are very inexpensive and easy to assemble with your own hands without the help of a qualified engineer (if you decide to do this, there are enough videos uploaded on the network, the request is homemade solar reflector). However, in practice they are used quite infrequently, one of the reasons for this is their rather large dimensions. Such concentrators, including home-made ones, are used in those places where the area and the space they occupy, which are not critical for its owner, allow it.

Such a disadvantage is absent in the prism concentrator of solar radiation. In addition, this equipment can partially concentrate a part of the diffusion radiation, thereby significantly increasing the power of the generated energy ray flux. The trihedral prism, with the use of which this mechanism is built, simultaneously performs the functions of both the initiator of the radiation of the point of concentration of the beam, and the reception of this radiation. In addition to everything, the rear face of the polyhedron reflects the energy flow of the solar radiation received by the front face, and the side face is responsible for the emission of radiation. The principle of operation of this equipment is based on the mechanism of maximum reflective effect on the sun's rays until they hit the side face.

The reflex solar concentrator, in comparison with the refractory ones, functions by combining the energy of the beam of reflected solar radiation. Based on the shape of the structure, such concentrators are divided into subspecies and are called parabolic and parabolic. If you understand the efficiency of these devices, then the most powerful source of energy will be a parabolic concentrator, it produces up to 10 thousand units of concentration.

Parabolic concentrator delivers up to 10 thousand units of concentration

However, to create energy solar heating systems (especially for heating in winter), they mostly resort to installing parabolic or flat devices, and besides, such a system is easy to install with your own hands.

Solar concentrators their practical use and application

In principle, the main function of solar concentrators of any design is to collect the radiation coming from the sun and concentrate it at one point. To determine the scope of this energy is the choice of the owner of this equipment. Using completely free and renewable energy, it is possible to heat water for household and hygiene needs. The amount of heated water will depend only on the size of the plate and the overall design of the concentrator. Smaller parabolic concentrators can be used as a cooking oven that will operate solely on concentrated solar radiation.

In winter, concentrators can be used as an additional source of sunlight for photovoltaic solar panels, thereby increasing their output power in conditions of lack of solar radiation.

Parabolic concentrators can be used as an oven for food preparation

In fact, the use of crystalline batteries to increase the efficiency is a pretty good idea, given the low cost of concentrators. Moreover, you will not need a patent for such a design. It will turn out a kind of homemade solar power supply system.

It is also possible to use the device as an autonomous source of energy for the Stirling engine (a patent for such an engine was obtained by its inventor a very long time ago). Concentrators of the parabolic group create a temperature in the range from 300 to 400 °C at the point of collection of sunlight.

If you put a metal stand for dishes and place a kettle on it in the area of ​​​​concentration of rays coming from a relatively small plate, you can boil water without using electricity without any problems. By placing the heater at the point of energy concentration, you will quickly heat up running water in large enough volumes for further use in household needs. You can water the garden, wash the dishes, take a shower.

By placing a Stirling engine correctly selected in terms of power in the focus of the beam, you will get a small thermal and electric station.

Stirling engines are designed to work in tandem with a solar concentrator

For example, one company called Qnergy has developed and filed a patent, launching the QB-3500 Stirling engines, which are designed specifically to work in tandem with a solar reflector solar concentrator. At its core, such a device can be considered an electric current generator, where the Stirling engine performs the main function. Note that such a system also requires batteries to store the energy received. Such a power plant produces an electric current with a power of 3500 watts. The output inverter produces a standard voltage of 220 volts, a frequency of 50 Hz. This power of electric current is enough for you to fully meet the needs of a house in which a family of four lives. The use of such batteries is also effective for a country house. The concentrator installed on your site will have the appearance of a satellite dish without violating the external aesthetics.

By the way, one of the manufacturers registered a patent for a device where, using the principle of the Stirling engine, you can create a system that will basically operate a reciprocating or rotational movement (does not require the installation of batteries). An example of such a system is a water pump for a well or other purposes.

The parabolic concentrator must be systematically rotated to follow the rays of the sun as the earth rotates during the day

The main disadvantage that a parabolic concentrator has is that it must be systematically monitored by turning it in the direction of the sun's rays as the earth rotates during the day. Where concentrators are used at large thermal power plants on an industrial scale, special systems for tracking the movement of the sun are additionally mounted to the battery group. Such systems rotate the mirrors following its movement. This guarantees a constant and efficient reception of the incoming solar radiation at the most effective angle. But the use of such equipment in private, most likely, will not be very appropriate, due to the fact that the acquisition costs will be much higher than the cost of a standard tripod-mounted reflector.

How to make a solar radiation concentrator yourself?

To study this issue, one can refer to the experience of the inventor from Vladivostok, Yuri Rylov, who has a patent for the heating system he created. For a long time, his large country house, with a total area of ​​​​more than 400 square meters, is completely heated on the basis of a battery system, where the coolant is heated by a solar concentrator.

Yury Rylov's concentrator works more than twice as efficiently as solar panels

The entire system, for which he received a patent as a result, was developed by the craftsman himself. Its concentrator works more than twice as efficiently as solar panels.

There are a number of reasons for this, one of them is the system of concentrators, for which the inventor received a patent, it accumulates the energy of almost the entire incoming spectrum of solar radiation. The next reason is that the system was supplemented with a sun tracking mechanism (considering the scope of the equipment in this case, this may be justified).

However, problems arose with the introduction of the system into mass production. Under the created device more than five years ago, the inventor received a patent of the Russian Federation, but so far it has not received wide industrial distribution. This is rather strange, since according to Rylov, his concentrator allows you to heat the entrance of a five-story house, providing it with hot water. For eight hours of operation, the equipment heats up a cubic meter of water. During the same time, the concentrator will produce 80 kW of electricity. In addition, the inventor faced the problem of protecting intellectual property in Russia. It is necessary to deal with fixing the ownership of your device in those countries where it is possible to establish such production, officials do not help to obtain a patent abroad.

The easiest way to build your own homemade hub is to make one from an old satellite dish.

So, the easiest way to build your own homemade hub is to make it based on an old satellite dish. Before assembling the mechanism, determine the purpose of its use, and then select the location of the concentrator. Thoroughly clean the antenna and attach a reflective film to the working side.

For even laying of the film and to avoid possible wrinkles, cut the film into strips no larger than fifty millimeters. If you decide to use the concentrator as a solar oven, it will be better when you make a hole about 70 millimeters in diameter in the central part of the plate. Pass the fastening of the food container through it. The device guarantees a fixed position of the container with the heated object during the turns of the device behind the sun.

If you only have a plate with a small diameter at your disposal, it is worth cutting the tape into strips of 100 millimeters. Each strip must be glued separately, carefully and accurately aligning the joints.

When you have finished pasting the reflective element, determine where the point of concentration of the rays is. This must be done because the shape of the dish often does not guarantee the coincidence of the focal point and the location of the signal receiving head.

Homemade solar concentrator oven

To begin with, it is worth identifying the place of concentration, for this, put on sunglasses. Take a wooden board and tight mittens. Point the reflector towards the sun and focus the captured rays on the board, then adjust the distance until you get the most efficient, concentrated beam of energy, do this until you get its smallest size. The mittens you wear will protect your skin from sunburn if you accidentally put your hands in the focus area of ​​​​the rays. After you determine the point of concentration, you will only have to fix the structure and finish its installation in the optimal place. As they say in inventor circles, "The only thing left to do is get a patent." Use the results of your work, getting an inexhaustible and free source of energy.

Stirling engine can be assembled using improvised, common materials

There are many options for manufacturing concentrators based on solar radiation. In the same way, you yourself, using improvised, common materials, can assemble a Stirling engine (it is really possible, although, at first glance, it seems unattainable), and you can use the capabilities of this engine for a variety of purposes for a long time. All restrictions depend only on your patience and imagination.

Details Published: 10/12/2015 08:32

This free step-by-step guide contains all the information you need to build your own 0.5 kW solar concentrator. 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, as GoSol's solar plant is named, will take up approximately 1.5 cubic meters of space. Work on its manufacture will take about a week. The materials for its construction will be iron corners, plastic boxes, steel bars, and the main working element - a reflective hemisphere - is proposed to be made from pieces of an ordinary bathroom mirror.

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

The GoSol instruction can be used not only for the creation and practical application, but also for the sale of solar concentrators, which will help to significantly lower the threshold for accessing 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 in other ways.

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

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. If you believe the ancient writers Plutarch and Polybius, then the first person to practically use solar energy was Archimedes, who, using some optical devices he invented, managed to collect the sun's rays into a powerful beam and burn the Roman fleet.

In essence, 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 at the focus of this concentrator, the temperature could reach 300 ° C - 400 ° C, which is quite enough to ignite the wooden ships of the Roman fleet. One can only guess what kind of device Archimedes invented, although, according to modern ideas, he had only two options.

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

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

Refractory Solar Concentrator

The prismatic concentrator of solar radiation is deprived of this shortcoming. Moreover, such a device is also capable of concentrating part of the diffuse radiation, which significantly increases the power of the light beam. The trihedral prism, on the basis of which such a concentrator is built, is both a radiation receiver and a source of an energy beam. In this case, the front face of the prism receives radiation, the back face reflects, and radiation is already emerging from the side face. The operation of such a device is based on the principle of total internal reflection of rays before they hit the side face of the prism.

Unlike refractor concentrators, reflex concentrators work on the principle of collecting reflected sunlight into an energy beam. According to their design, they are divided into flat, parabolic and parabolic-cylindrical concentrators. If we talk about the effectiveness of each of these types, then the highest degree of concentration - up to 10,000 - is given by parabolic concentrators. But for the construction of solar heating systems, mainly flat or parabolic-cylindrical systems are used.

Parabolic (reflector) solar concentrators

Practical application of solar concentrators

Actually, the main task of any solar concentrator is to collect the radiation of the sun into a single energy beam. And you can use this energy in various 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 cooker.

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 about 300°C - 400°C. If, for example, a stand for a kettle or frying pans is placed in the focus of such a relatively small mirror, then you get a solar oven, on which you can cook food and boil water very quickly. A heater with a heat carrier placed at the focus will quickly heat up even running water, which can then be used for household purposes, for example, for showering, washing dishes.

The simplest scheme for heating water with a solar concentrator

If a Stirling engine of suitable power is placed at the focus of a parabolic mirror, then a small thermal power plant can be obtained. For example, Qnergy has developed and launched 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 an electric current with a power of 3500 watts. The output of the inverter is a standard voltage of 220 volts 50 hertz. This is quite enough to provide electricity to a house for a family of 4, a dacha.

By the way, using the principle of operation of Stirling engines, many craftsmen make devices with their own hands that use rotational 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 installations, special tracking systems are used that rotate mirrors or refractors following the movement of the sun, thereby ensuring the reception and concentration of the maximum amount of solar energy. For individual use, it would hardly be advisable to use such tracking devices, since their cost can significantly exceed the cost of a simple reflector on a conventional 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 hub will be used, and then, based on this, choose the 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 dish.

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 you intend to use the concentrator as a solar oven, it is recommended to cut a hole in the center of the dish with a diameter of about 5 - 7 centimeters. Through this hole, a bracket with a support for dishes (burner) will be passed. This will ensure the immobility of the container with the cooked food when the reflector is turned to the sun.

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

Homemade solar concentrator - oven

To determine the focal point, you need to arm yourself with dark glasses, a wooden plank and thick gloves. Then you need to direct the mirror directly at the sun, catch a sunbeam on the board and, bringing the board closer or further away from the mirror, find the point where this sunbeam will have the minimum size - a small point. Gloves are needed in order to protect your hands from burns if they accidentally fall into the beam area. Well, when the focus point is found, it remains only 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 improvised materials yourself. And you can use this engine for a variety of purposes. How much imagination, desire and patience is enough.