Efficiency-enhancing mirror concentrators for solar collectors. Solar panels and collectors: theory, applications, working homemade Solar wedge concentrators

(Canada) has developed a versatile, powerful, efficient and one of the most economical solar parabolic concentrators (CSP - Concentrated Solar Power) with a diameter of 7 meters, both for ordinary homeowners and for industrial use. The company specializes in the production of mechanical devices, optics and electronics, which helped it create a competitive product.

According to the manufacturer's assessment, the SolarBeam 7M solar concentrator is superior to other types of solar devices: flat solar collectors, vacuum collectors, solar concentrators of the "trough" type.

External view of Solarbeam solar concentrator

How it works?

The automatic solar concentrator tracks the movement of the sun in 2 planes and directs the mirror exactly at the sun, allowing the system to collect maximum solar energy from dawn to late sunset. Regardless of the season or place of use, SolarBeam maintains a sun pointing accuracy of up to 0.1 degrees.

The rays incident on the solar concentrator are focused at one point.

Calculations and design of SolarBeam 7M

Stress - testing

3D modeling and software stress testing methods were used to design the system. Tests are performed according to the FEM methodology (Finite Element Analysis) to calculate the stresses and displacements of parts and assemblies under the influence of internal and external loads in order to optimize and verify the design. This precise testing ensures that SolarBeam can operate under extreme wind and climatic conditions. SolarBeam has successfully passed wind load simulations up to 160 km/h (44 m/s).

Stress testing of the connection between the parabolic reflector frame and the column

Solarbeam hub mount photo

Stress Testing a Solar Concentrator Rack

Production level

Often, the high cost of manufacturing parabolic concentrators prevent their mass use in individual construction. The use of stamps and large segments of reflective material have reduced production costs. Solartron has used many of the innovations used in the automotive industry to reduce cost and increase output.

Reliability

SolarBeam has been tested in the harsh conditions of the north, providing high performance and durability. SolarBeam is designed for all weather conditions, including high and low ambient temperatures, snow load, icing and strong winds. The system is designed for 20 or more years of operation with minimal maintenance.

The SolarBeam 7M parabolic mirror can hold up to 475 kg of ice. This is approximately equal to 12.2 mm thick ice cover over the entire area of ​​38.5 m2.
The installation works normally in snowfalls due to the curved design of the mirror sectors and the ability to automatically perform "auto clearing of snow".

Performance (comparison with vacuum and flat collectors)

Q / A = F’(τα)en Kθb(θ) Gb + F’(τα)en Kθd Gd -c6 u G* - c1 (tm-ta) - c2 (tm-ta)2 – c5 dtm/dt

The efficiency for non-concentrating solar collectors was calculated using the following formula:

Efficiency = F Collector Efficiency - (Slope*Delta T)/G Solar Radiation

The performance curve for the SolarBeam concentrator shows an overall high efficiency over the entire temperature range. Flat plate and evacuated solar collectors show lower efficiency when higher temperatures are required.

Comparison graphs of Solartron and flat/vacuum solar collectors

Efficiency (COP) of Solartron as a function of temperature difference dT

It is important to note that the diagram above does not account for heat loss from wind. In addition, the data above indicates the maximum efficiency (at noon) and does not reflect the efficiency during for. The data is given for one of the best flat and vacuum collectors. In addition to high efficiency, SolarBeamTM produces an additional 30% more energy due to the dual axis tracking of the sun. In geographical regions where low temperatures prevail, the efficiency of flat and vacuum collectors is significantly reduced due to the large absorber area. SolarBeamTM has an absorber area of ​​only 0.0625 m2 compared to an energy collection area of ​​15.8 m2, thus achieving low heat loss.

Please also note that due to the dual axis tracking system, the SolarBeamTM hub will always operate at maximum efficiency. The effective area of ​​the SolarBeam collector is always equal to the actual surface area of ​​the mirror. Flat (fixed) collectors lose potential energy according to the equation below:
PL = 1 - COS i
where PL is the loss in energy in %, of the maximum at displacement in degrees)

Control system

SolarBeam controls use "EZ-SunLock" technology. With this technology, the system can be quickly installed and configured anywhere in the world. The tracking system tracks the sun with an accuracy of 0.1 degrees and uses an astronomical algorithm. The system has the possibility of general dispatching through remote networks.

Abnormal situations in which the "dish" will automatically be parked in a safe position.

• If the coolant pressure in the circuit drops below 7 PSI
• When the wind speed is more than 75km/h
• In the event of a power outage, the UPS (uninterruptible power supply) moves the dish to a safe position. When power is restored, automatic sun tracking continues.

Monitoring

In any case, and especially for industrial applications, it is very important to know the status of your system to ensure reliability. You must be warned before a problem occurs.

SolarBeam has the ability to monitor through the SolarBeam Remote Dashboard. This panel is easy to use and provides important SolarBeam status, diagnostics and energy production information.

Remote configuration and management

SolarBeam can be remotely configured and changed on the fly. The "dish" can be controlled remotely using a mobile browser or PC, simplifying or eliminating on-site control systems.

Alerts

In the event of an alarm or service request, the device sends an e-mail message to designated service personnel. All alerts can be customized according to user preferences.

Diagnostics

SolarBeam has remote diagnostic capabilities: system temperatures and pressures, energy production, etc. At a glance, you can see the status of the system.

Reporting and charts

If energy production reports are needed, they can be easily obtained for each "dish". The report can be in the form of a graph or a table.

Mounting

SolarBeam 7M was originally designed for large-scale CSP installations, so installation was made as simple as possible. The design allows quick assembly of the main components and does not require optical alignment, which makes installation and start-up of the system inexpensive.

Installation time

A team of 3 can install one SolarBeam 7M from start to finish in 8 hours.

Accommodation Requirements

SolarBeam 7M is 7 meters wide with 3.5 meters of indentation. When installing multiple SolarBeam 7Ms, each system should be given an area of ​​approximately 10 x 20 meters to ensure maximum solar collection with the least amount of shading.

Assembly

The parabolic hub is designed to be assembled on the ground using a mechanical lift system, allowing for quick and easy installation of trusses, mirror sectors and mounts.

Areas of use

Electricity generation with ORC (Organic Rankine Cycle) installations.

Industrial water desalination plants

Thermal energy for the desalination plant can be supplied by SolarBeam

In any industry where a lot of thermal energy is required for the technological cycle, such as:

• Food (cooking, sterilization, obtaining alcohol, washing)
• Chemical industry
• Plastic (Heating, exhaust, separation, …)
• Textile (bleaching, washing, pressing, steaming)
• Petroleum (sublimation, clarification of petroleum products)
• And much more

Installation location

A suitable location for installation are regions that receive at least 2000 kWh of sunlight per m2 per year (kWh/m2/year). I consider the following regions of the world to be the most promising producers:

• Regions of the former Soviet Union
• Southwestern USA
• Central and South America
• North and South Africa
• Australia
• Mediterranean countries in Europe
• Middle East
• Desert plains of India and Pakistan
• Regions of China

Solarbeam-7M Model Specification

• Peak power - 31.5 kW (at a power of 1000 W / m2)
• The degree of energy concentration - more than 1200 times (spot 18cm)
• Maximum focus temperature - 800°С
• Maximum coolant temperature - 270°С
• Operational efficiency - 82%
• Reflector diameter - 7m
• The area of ​​the parabolic mirror - 38.5m2
• Focal length - 3.8m
• Power consumption of servomotors - 48W+48W / 24V
• Wind speed during operation - up to 75km/h (20m/s)
• Wind speed (in safe mode) - up to 160 km / h
• Sun tracking in azimuth - 360°
• Sun tracking vertical - 0 - 115°
• Support height - 3.5m
• Reflector weight - 476 kg
• Total weight -1083 kg
• Absorber size - 25.4 x 25.4 cm
• Absorber area -645 cm2
• The volume of the coolant in the absorber - 0.55 liters

Reflector overall dimensions

The main task of a solar collector is to convert the energy received from the sun into electricity. The principle of operation and the design of the equipment are simple, so it is technically easy to make it. As a rule, the received energy is used for heating buildings. Making a solar collector for heating a house with your own hands must begin with the selection of all components.

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Design and principle of operation

Heating a house with the help of converting solar energy into electrical energy is used, as a rule, as an additional source of heat, and not the main one. On the other hand, if you install a high-power structure, and convert all the appliances in the house to electricity, then you can only get by with a solar collector.

But it is worth remembering that heating with the help of solar collectors without additional heat sources is possible only in the southern regions. In this case, there should be a lot of panels. They must be positioned in such a way that they do not have a shadow (for example, from trees). Panels should be placed with the front side in the direction that is maximally illuminated by the sun throughout the day.

Solar energy concentrators

Although today there are many varieties of such devices, the principle of operation is the same for all. Any scheme takes solar energy and transfers it to the consumer, representing a circuit with a serial arrangement of devices. Components that produce electricity are solar panels or collectors.

The collector consists of tubes that are connected in series with the inlet and outlet. They can also be arranged in the form of a coil. Inside the tubes is process water or a mixture of water and antifreeze. Sometimes they are filled with just air flow. The circulation is carried out due to physical phenomena, such as evaporation, changes in the state of aggregation, pressure and density.

Absorbers perform the function of collecting solar energy. They have the form of a solid black metal plate or a structure of many plates interconnected by tubes.

For the manufacture of the housing cover, materials with high light transmission are used. Often this is either plexiglass or tempered types of ordinary glass. Polymeric materials are sometimes used, but plastic collectors are not recommended. This is due to its large expansion from heating by the sun. As a result, depressurization of the housing may occur.

If the system will be operated only in autumn and spring, then water can be used as a heat carrier. But in the winter it must be replaced with a mixture of antifreeze and water. In classical designs, the role of the coolant is played by air that moves through the channels. They can be made from a regular profiled sheet.

Experience in operating a solar battery made independently (solar battery part 3).

If the collector needs to be installed to heat a small building that is not connected to an autonomous heating system of a private house or centralized networks, then a simple system with one circuit and a heating element at its beginning will do. The scheme is simple, but the feasibility of its installation is disputed, since it will only work in sunny summer. However, circulation pumps and additional heaters are not required for its operation.

With two circuits, everything is much more complicated, but the number of days when electricity will be actively generated increases several times. In this case, the collector will process only one circuit. Most of the load is placed on a single device that runs on electricity or another type of fuel.

Although the performance of the device directly depends on the number of sunny days per year, and the price is too high, it is still very popular among the population. No less common is the production of solar heat exchangers with their own hands.



Temperature classification

Solar systems are classified according to various criteria. But in devices that can be made independently, you should pay attention to the type of coolant. Such systems can be divided into two types:

• use of various liquids;
• air structures.

The former are used most often. They are more productive and allow you to directly connect the collector to the heating system. Temperature classification is also common. within which the device can operate:



DIY solar battery Part11

The last type of solar systems works thanks to a very complex principle of solar energy transmission. The equipment needs a lot of space. If you place it in a country cottage, then it will occupy the predominant part of the site. To produce energy, you will need special equipment, so it will be almost impossible to make such a solar system on your own.






DIY manufacturing

The process of making a solar heater with your own hands is quite exciting, and the finished design will bring many benefits to the owner. Thanks to such a device, it is possible to solve the problem of space heating, water heating and other important household tasks.



Materials for self-production

An example is the process of creating a heating device that will supply heated water to the system. The cheapest way to produce a solar collector is to use wooden blocks and plywood as the main materials, as well as chipboard boards. As an alternative, you can use aluminum profiles and metal sheets, but they will cost more.

All materials must be moisture resistant, that is, meet the requirements for outdoor use. Qualitatively manufactured and installed solar collector can serve from 20 to 30 years. In this regard, the materials must have the necessary performance characteristics for use throughout the entire period. If the case is made of wood or chipboard, then to extend the service life it is impregnated with water-polymer emulsions and varnish.

Overview: Homemade solar panel (battery).

The necessary materials for manufacturing can either be bought on the market in the public domain, or you can make a design from improvised materials that can be found in any household. Therefore, the main thing you need to pay attention to is the price of materials and components.

Arrangement of thermal insulation

To reduce heat loss, insulating material is laid on the bottom of the box. For it, you can use foam, mineral wool, etc. Modern industry provides a large selection of different heaters. For example, using foil would be a good option. It will not only prevent heat loss, but will also reflect the sun's rays, which means it will increase the heating of the coolant.

In the case of using polystyrene foam or polystyrene for insulation, grooves can be cut for the tubes and mounted in this way. As a rule, the absorber is fixed to the bottom of the housing and laid on the insulating material.

Collector heat sink

The heat sink of the solar collector is an absorbent element. It is a system consisting of tubes through which the coolant moves, and other parts, usually made from copper sheets.

The best material for the tubular part is copper. But home craftsmen invented a cheaper option - polypropylene hoses, which are twisted into a spiral shape. Fittings are used to connect to the system at the inlet and outlet.

Improvised materials and means are allowed to use various, that is, almost any that are on the farm. A do-it-yourself heat collector can be made from an old refrigerator, polypropylene and polyethylene pipes, steel panel radiators and other improvised means. An important factor when choosing a heat exchanger is the thermal conductivity of the material from which it is made.




The ideal option for creating a homemade water collector is copper. It has the highest thermal conductivity. But the use of copper pipes instead of polypropylene does not mean that the device will produce much more warm water. On equal terms, copper pipes will be 15-25% more efficient than installing polypropylene counterparts. Therefore, the use of plastic is also advisable, besides, it is much cheaper than copper.

When using copper or polypropylene, all connections (threaded and welded) must be sealed. Possible arrangement of pipes - parallel or in the form of a coil. The top of the main structure with tubes is covered with glass. With the form in the form of a coil, the number of connections and, accordingly, the possible formation of leaks is reduced, and a uniform movement of the coolant through the tubes is also ensured.

Not only glass can be used to cover the box. For these purposes, translucent, matte or corrugated materials are used. You can use acrylic modern analogues or monolithic polycarbonates.

In the manufacture of the classic version, you can use tempered glass or plexiglass, polycarbonate materials, etc. A good alternative would be the use of polyethylene.

It is important to consider that the use of analogues (corrugated and matte surfaces) helps to reduce the light transmission. In factory models, special solar glass is used for this. It has a little iron in its composition, which ensures low heat loss.

Accumulative tank of the installation

To create a storage tank, you can use any container with a volume of 20 to 40 liters. A scheme with several tanks is also used, which are interconnected into one system. It is desirable to insulate the tank, otherwise the heated water will quickly cool down.

If you look, then there is no accumulation in this system, and the heated coolant must be used immediately. Therefore, the storage tank is used for:

• maintaining pressure in the system;
• antechamber replacement;
• hot water distribution.

Of course, a solar collector made by oneself at home will not provide the quality and efficiency characteristic of factory-made models. Using only improvised materials, it is not worth talking about a high efficiency. In industrial designs, such indicators are several times higher. However, the financial costs will be much less here, as improvised means are used. A do-it-yourself solar installation will significantly increase the level of comfort in a country house, as well as reduce the cost of other energy resources.

(Canada) has developed a versatile, powerful, efficient and one of the most economical solar parabolic concentrators (CSP - Concentrated Solar Power) with a diameter of 7 meters, both for ordinary homeowners and for industrial use. The company specializes in the production of mechanical devices, optics and electronics, which helped it create a competitive product.

According to the manufacturer's assessment, the SolarBeam 7M solar concentrator is superior to other types of solar devices: flat solar collectors, vacuum collectors, solar concentrators of the "trough" type.

External view of Solarbeam solar concentrator

How it works?

The automatic solar concentrator tracks the movement of the sun in 2 planes and directs the mirror exactly at the sun, allowing the system to collect maximum solar energy from dawn to late sunset. Regardless of the season or place of use, SolarBeam maintains a sun pointing accuracy of up to 0.1 degrees.

The rays incident on the solar concentrator are focused at one point.

Calculations and design of SolarBeam 7M

Stress - testing

3D modeling and software stress testing methods were used to design the system. Tests are performed according to the FEM methodology (Finite Element Analysis) to calculate the stresses and displacements of parts and assemblies under the influence of internal and external loads in order to optimize and verify the design. This precise testing ensures that SolarBeam can operate under extreme wind and climatic conditions. SolarBeam has successfully passed wind load simulations up to 160 km/h (44 m/s).

Stress testing of the connection between the parabolic reflector frame and the column

Solarbeam hub mount photo

Stress Testing a Solar Concentrator Rack

Production level

Often, the high cost of manufacturing parabolic concentrators prevent their mass use in individual construction. The use of stamps and large segments of reflective material have reduced production costs. Solartron has used many of the innovations used in the automotive industry to reduce cost and increase output.

Reliability

SolarBeam has been tested in the harsh conditions of the north, providing high performance and durability. SolarBeam is designed for all weather conditions, including high and low ambient temperatures, snow load, icing and strong winds. The system is designed for 20 or more years of operation with minimal maintenance.

The SolarBeam 7M parabolic mirror can hold up to 475 kg of ice. This is approximately equal to 12.2 mm thick ice cover over the entire area of ​​38.5 m2.
The installation works normally in snowfalls due to the curved design of the mirror sectors and the ability to automatically perform "auto clearing of snow".

Performance (comparison with vacuum and flat collectors)

Q / A = F’(τα)en Kθb(θ) Gb + F’(τα)en Kθd Gd -c6 u G* - c1 (tm-ta) - c2 (tm-ta)2 – c5 dtm/dt

The efficiency for non-concentrating solar collectors was calculated using the following formula:

Efficiency = F Collector Efficiency - (Slope*Delta T)/G Solar Radiation

The performance curve for the SolarBeam concentrator shows an overall high efficiency over the entire temperature range. Flat plate and evacuated solar collectors show lower efficiency when higher temperatures are required.

Comparison graphs of Solartron and flat/vacuum solar collectors

Efficiency (COP) of Solartron as a function of temperature difference dT

It is important to note that the diagram above does not account for heat loss from wind. In addition, the data above indicates the maximum efficiency (at noon) and does not reflect the efficiency during for. The data is given for one of the best flat and vacuum collectors. In addition to high efficiency, SolarBeamTM produces an additional 30% more energy due to the dual axis tracking of the sun. In geographical regions where low temperatures prevail, the efficiency of flat and vacuum collectors is significantly reduced due to the large absorber area. SolarBeamTM has an absorber area of ​​only 0.0625 m2 compared to an energy collection area of ​​15.8 m2, thus achieving low heat loss.

Please also note that due to the dual axis tracking system, the SolarBeamTM hub will always operate at maximum efficiency. The effective area of ​​the SolarBeam collector is always equal to the actual surface area of ​​the mirror. Flat (fixed) collectors lose potential energy according to the equation below:
PL = 1 - COS i
where PL is the loss in energy in %, of the maximum at displacement in degrees)

Control system

SolarBeam controls use "EZ-SunLock" technology. With this technology, the system can be quickly installed and configured anywhere in the world. The tracking system tracks the sun with an accuracy of 0.1 degrees and uses an astronomical algorithm. The system has the possibility of general dispatching through remote networks.

Abnormal situations in which the "dish" will automatically be parked in a safe position.

• If the coolant pressure in the circuit drops below 7 PSI
• When the wind speed is more than 75km/h
• In the event of a power outage, the UPS (uninterruptible power supply) moves the dish to a safe position. When power is restored, automatic sun tracking continues.

Monitoring

In any case, and especially for industrial applications, it is very important to know the status of your system to ensure reliability. You must be warned before a problem occurs.

SolarBeam has the ability to monitor through the SolarBeam Remote Dashboard. This panel is easy to use and provides important SolarBeam status, diagnostics and energy production information.

Remote configuration and management

SolarBeam can be remotely configured and changed on the fly. The "dish" can be controlled remotely using a mobile browser or PC, simplifying or eliminating on-site control systems.

Alerts

In the event of an alarm or service request, the device sends an e-mail message to designated service personnel. All alerts can be customized according to user preferences.

Diagnostics

SolarBeam has remote diagnostic capabilities: system temperatures and pressures, energy production, etc. At a glance, you can see the status of the system.

Reporting and charts

If energy production reports are needed, they can be easily obtained for each "dish". The report can be in the form of a graph or a table.

Mounting

SolarBeam 7M was originally designed for large-scale CSP installations, so installation was made as simple as possible. The design allows quick assembly of the main components and does not require optical alignment, which makes installation and start-up of the system inexpensive.

Installation time

A team of 3 can install one SolarBeam 7M from start to finish in 8 hours.

Accommodation Requirements

SolarBeam 7M is 7 meters wide with 3.5 meters of indentation. When installing multiple SolarBeam 7Ms, each system should be given an area of ​​approximately 10 x 20 meters to ensure maximum solar collection with the least amount of shading.

Assembly

The parabolic hub is designed to be assembled on the ground using a mechanical lift system, allowing for quick and easy installation of trusses, mirror sectors and mounts.

Areas of use

Electricity generation with ORC (Organic Rankine Cycle) installations.

Industrial water desalination plants

Thermal energy for the desalination plant can be supplied by SolarBeam

In any industry where a lot of thermal energy is required for the technological cycle, such as:

• Food (cooking, sterilization, obtaining alcohol, washing)
• Chemical industry
• Plastic (Heating, exhaust, separation, …)
• Textile (bleaching, washing, pressing, steaming)
• Petroleum (sublimation, clarification of petroleum products)
• And much more

Installation location

A suitable location for installation are regions that receive at least 2000 kWh of sunlight per m2 per year (kWh/m2/year). I consider the following regions of the world to be the most promising producers:

• Regions of the former Soviet Union
• Southwestern USA
• Central and South America
• North and South Africa
• Australia
• Mediterranean countries in Europe
• Middle East
• Desert plains of India and Pakistan
• Regions of China

Solarbeam-7M Model Specification

• Peak power - 31.5 kW (at a power of 1000 W / m2)
• The degree of energy concentration - more than 1200 times (spot 18cm)
• Maximum focus temperature - 800°С
• Maximum coolant temperature - 270°С
• Operational efficiency - 82%
• Reflector diameter - 7m
• The area of ​​the parabolic mirror - 38.5m2
• Focal length - 3.8m
• Power consumption of servomotors - 48W+48W / 24V
• Wind speed during operation - up to 75km/h (20m/s)
• Wind speed (in safe mode) - up to 160 km / h
• Sun tracking in azimuth - 360°
• Sun tracking vertical - 0 - 115°
• Support height - 3.5m
• Reflector weight - 476 kg
• Total weight -1083 kg
• Absorber size - 25.4 x 25.4 cm
• Absorber area -645 cm2
• The volume of the coolant in the absorber - 0.55 liters

Reflector overall dimensions

Energy sources such as electricity, coal and gas are constantly becoming more expensive.

People need to think more about using greener systems heating.

Therefore, it was developed technical innovation in the field of alternative heat sources. Solar collectors have been used for this.

Solar collector for heating

The surface of this device has low reflectivity, due to which heat is absorbed. For space heating this mechanism uses the light of the sun and its infrared radiation.

To heat the water and heat the house, the power of a simple solar collector is enough. It depends on the design of the unit. A person can independently make the installation of equipment. For this, you do not need to use expensive tools and materials.

Reference. The efficiency of professional devices is 80—85% . Homemade ones are much cheaper, but their efficiency no more than 60-65%.

Design

The structure of the equipment is simple. The device is a rectangular plate consisting of several layers:

• framed anti-reflective tempered glass cover;
• absorber;
• bottom insulation;
• side insulation;
• pipeline;
• glass curtain;
• aluminum weatherproof case;
• connecting fittings.

The system includes 1-2 collectors, storage capacity and avankameru. The design is organized closed, so the sun's rays fall only into it and turn into heat.

Principle of operation

The basis of the operation of the installation is a thermosyphon. The coolant inside the equipment circulates on its own, which will help to abandon the use of the pump.

Heated water tends to rise, thereby pushing the cold water and transporting it to the heat source.

The collector is tubular radiator, which is mounted in a wooden box, one plane of which is made of glass. Pipes in the manufacture of the unit are used steel. The diversion and supply are carried out by pipes used in the plumbing device.

The structure works like this:

1. The collector converts solar energy into heat.
2. Fluid enters storage tank through the supply line.
3. The circulation of the coolant occurs independently or with the help of an electric pump. The liquid in the installation must meet several requirements: they will not evaporate at high temperatures, be non-toxic, frost-resistant. Usually take distilled water mixed with glycol in a ratio of 6:4.

solar concentrator

solar energy storage device has the function of a heat carrier. Serves to focus energy on the emitter receiver inside the product.

There are the following types:

• parabolic-cylindrical concentrators;
• concentrators on flat lenses ( fresnel lens);
• on spherical lenses;
• parabolic concentrators;
• solar towers.

Hubs reflect radiation from a large plane to a small one which helps to reach high temperatures. The liquid absorbs heat and moves to the heating object.

Important! The price of devices is not cheap, and also they require constant skilled maintenance. Such equipment is used in hybrid systems, most often on an industrial scale, and allows you to increase the performance of the collector.

Types of solar collectors

Currently, there are several varieties of solar heating collectors.

Flat, do-it-yourself installation

This device consists of a panel in which the absorber plate is mounted. This type of device is the most common. The cost of the units is affordable and depends on the type of coating, manufacturer, power and heating area. Prices for equipment of this type - from 12 thousand rubles.

Photo 1. Five flat-type solar collectors installed on the roof of a private house. The appliances are tilted.

Scope of application

Similar collectors often installed in private homes for room heating and hot water supply. Devices manage to heat water for a summer shower in the country. It is appropriate to operate them in warm and sunny weather.

Attention! Collector surface cannot be obscured by other buildings, trees and houses. This has a negative impact on performance. Equipment is mounted on the roof or facade of the building, as well as on any suitable surface.

You will also be interested in:

flat collector design

The composition of the device:

• protective glass;
• copper pipes;
• thermal insulation;
• absorbent surface with a high degree of absorption;
• aluminum frame.

The collector, which has a tubular coil, is a classic option. As an alternative in home-made designs, they use: polypropylene material, aluminum beverage cans, rubber garden hoses.

The bottom and edges of the system must be thermally insulated. If the absorber is in contact with the body, then heat loss is possible. The outer part of the device is protected by tempered glass with special properties. Antifreeze is taken as a coolant.

Operating principle

The liquid is heated and enters the storage tank, from which it moves to the collector in a cooled form. The structure is available in two versions.: single-circuit and double-circuit. In the first case the liquid goes straight to the tank, in the second- passes through a thin tube through the water in the tank, warming up the volume of the room. As it moves, it cools and moves back into the collector.

Photo 2. Scheme and principle of operation of a flat-type solar collector. The arrows indicate the parts of the device.

Advantages and disadvantages

Units of this type have the following advantages:

• high performance;
• low cost;
• long-term operation;
• reliability;
• the possibility of self-made installation and maintenance.

Flat-plate collectors are suitable for operation in southern areas with a warm climate. Their downside is high windage due to the large surface, so strong winds can disrupt the structure. Performance drops in cold winter weather. Ideally, the unit should be installed on the south side of the site or house.

Vacuum

device consists of separate tubes, combined at the top and forming a single panel. In fact, each of the tubes is an independent collector. This is an efficient modern look, usable even in cold weather. Vacuum devices are more complex in relation to flat ones, therefore they are more expensive.

Photo 3. Vacuum-type solar collector. The device consists of many tubes fixed in one structure.

Scope of application

Apply for hot water supply and heating of large visits. Most often used in summer cottages and in private households. Mounted on the facades of buildings, pitched or flat roofs, special supporting structures. They function in cold climates and with short daylight hours without compromising efficiency. Due to the high efficiency, they are also used on agricultural land, industrial enterprises. This type is common in European countries.

Design

The device includes:

• thermal storage (water tank);
• circuit for the circulation of the heat exchanger;
• the collector itself;
• sensors;
• receiver.

The design of the unit is a series of tubular profiles installed in parallel. The receiver and vacuum tubes are made of copper. The glass tube block is separated from the outer circuit, so that the activity of the collector does not stop when it fails 1-2 tubes. Polyurethane insulation is used as additional protection.

Reference. A distinctive feature of the collector is the composition of the alloy from which the pipes are made. This is aluminum coated and polyurethane protected copper.

Operating principle

Construction work based on zero vacuum thermal conductivity. An airless space is formed between the tubes, which reliably retains the heat generated from the sun's rays.

The vacuum manifold works like this:

• the energy of the sun is received by a tube inside a vacuum flask;
• the heated liquid evaporates and rises to the condensation area of ​​the pipe;
• the coolant flows down from the condensation zone;
• the cycle is repeated anew.

Thanks to this work much higher heat transfer and heat loss is low. Energy can be stored due to the vacuum layer, which effectively captures heat.

Photo 4. Scheme of the device of a vacuum solar collector. The components of the device are indicated by arrows.

Advantages and disadvantages

The advantages of this type of device:

• durability;
• stability in operation;
• affordable repair, it is possible to replace only one element that has failed, and not the entire structure;
• low windage, the ability to withstand gusts of wind;
• maximum absorption of solar energy.

The equipment is expensive, which can only be recouped in a few years after use. The price of components is also high, and their replacement may require the help of a professional. The system is not capable of self-cleaning from ice, snow, frost.

Types of vacuum manifolds

Products are of two types: with indirect and direct heat supply. The functioning of structures with indirect supply is carried out from the pressure in the pipes.

In devices with direct heat supply, the heat carrier container and glass vacuum devices are mounted to the frame at a certain angle, through a rubber connecting ring.

Equipment connects to the water lines through a constipation valve, and the fixing valve controls the water level in the tank.

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Air

Water has a much higher heat capacity than air. However, its use is associated with a number of everyday problems during operation (pipe corrosion, pressure control, change in physical state). Air collectors not so whimsical, have a simple design. Devices cannot be considered a full-fledged replacement for other types, but they are able to reduce utility costs.

Scope of application

This type of equipment is used in air heating of houses, drainage systems and for air recovery (treatment). It is used for drying agricultural products.

Design

Consists of:

• an adsorber, a heat-absorbing panel inside the case;
• external insulation made of tempered glass;
• thermal insulation between the housing wall and the absorber;
• sealed housing.

Photo 5. Air solar collector for heating a house. The device is fixed vertically on the wall of the building.

The device is located close to the heating object due to large heat losses in the air lines.

Operating principle

Unlike water collectors, air do not accumulate heat, but immediately release it into insulation. Sunlight hits the outer part of the device and heats it up, the air begins to circulate in the structure and heats the room.

You can design an air manifold yourself, using improvised materials in the manufacture: beer cans made of copper or aluminum, chipboard panels, aluminum and metal sheets.

Photo 6. Scheme of the device of an air solar collector. The drawing shows the main parts of the device.

Advantages and disadvantages

Advantages:

• low cost of the device;
• the possibility of self-installation and repair;
• simplicity of design.

Of the shortcomings: limited scope (only heating), low efficiency. At night, the equipment will work to cool the air if it is not closed.

Choosing a set of solar collectors for the heating system

Device selection depends on the goals for which the work of the structure will be directed. The solar system is used to support air, provide hot water, heat water for the pool.

Power

To calculate the possible output of a solar system, you need to know 2 parameters: solar insolation in a certain region at the right time of the year and the effective absorption area of ​​the collector. These numbers must be multiplied.

Is it possible to use the collector in winter

Vacuum devices cope with work in cold climates. flat show low performance in cold weather and are better suited for the southern regions.

Less suitable for functioning in the cold aerial structure as at night it is not able to heat the air.

Trouble with heavy rainfall, because in winter the equipment often falls asleep with snow and regular cleaning is required. Frosty air takes away the accumulated heat, and the collector itself can be damaged by hail.

Scope consideration

In industry, the use of solar systems is more common. Solar energy is used in the operation of power plants, steam generators, water desalination plants. For heating water, heating a summer house or a bath in domestic conditions, vacuum collectors are more often installed, less often flat ones. Air systems help reduce the cost of heating by heating the air during the day.

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

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

parabolic antenna.

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

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

You will need a roll of aluminum foil or lavsan mirror film used for greenhouses. Glue with which the film will be glued to the parabola.

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

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

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

Such a film can be ordered on Aliexpress, if you don’t find it in stores

This is almost as easy to do as it sounds. It is only necessary to take into account that if the antenna, for example, has a diameter of 2.5 m, and the film is 1 m wide, then it is not necessary to cover the antenna with a film in two passes, folds and irregularities will form, which will worsen the focusing of solar energy. Cut it into small strips and fix it to the antenna with glue. Make sure the antenna is clean before sticking the film. If there are places where the paint is swollen, clean them with sandpaper. You need to smooth out all the irregularities. Please note that the LNB must be removed from its place, otherwise it may melt. After sticking the film and installing the antenna in place, do not put your hands or face near the head attachment point - you risk serious sunburn.

Step 2 tracking system.

As it was written above - the author bought a tracking system on Ebay. You can also look for rotary sun tracking systems. But I found a simple circuit with a penny price that tracks the position of the sun quite accurately.

Parts list:
(downloads: 450)
* U1/U2 - LM339
* Q1 - TIP42C
*Q2-TIP41C
*Q3-2N3906
*Q4-2N3904
* R1 - 1meg
* R2 - 1k
* R3 - 10k
* R4 - 10k
* R5 - 10k
* R6 - 4.7k
* R7 - 2.7k
* C1 - 10n ceramic
* M - DC motor up to 1A
* LEDs - 5mm 563nm

Video of the operation of the solar tracker according to the scheme from the archive

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

For those interested, the photo was taken from here:

Step 3 Creating a heat exchanger-collector

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

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

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

Step 4 Putting it all together and trying it out.

Now you have a mirrored parabola, a solar tracking module placed in a waterproof container, or a plastic container, a complete collector. All that remains to be done is to install the collector in place and test it in operation. You can go further and improve the design by making something like a pan with insulation and putting it on the back of the collector. The tracking mechanism must track movement from east to west, i.e. turn during the day to follow the sun. And the seasonal positions of the star (up / down) can be adjusted manually once a week. You can, of course, add a tracking mechanism vertically as well - then you will get almost automatic operation of the installation. If you are planning to use the water for pool heating or as hot water in the plumbing, you will need a pump that will pump the water through the manifold. If you heat a container of water, you need to take measures to avoid boiling water and explosion of the tank. You can do this using