Types of solar panels: a comparative overview of designs and tips for choosing panels
Alternative energy is developing as much as possible in Europe, showing the results of its promise. New types of solar panels appear, their efficiency increases.
If you want to ensure the operation of an industrial building or residential building due to the energy of the sun, you must first learn about the differences in equipment, understand which solar panels are suitable for the climatic conditions of a particular region.
We will help to understand this issue. The article describes the principle of operation of photovoltaic converters, provides an overview of different types of solar panels with an indication of their characteristics, advantages and disadvantages. After reading the material, you can make the right choice for arranging an effective solar system.
The content of the article:
- The principle of operation of solar panels
- Types of Photoelectric Converters
- Characteristics of silicon-based panels
- Overview of silicon-free devices
- Which solar panel to choose?
- Conclusions and useful video on the topic
The principle of operation of solar panels
The vast majority of solar panels are physically photovoltaic converters. The electricity generating effect occurs at the site of the semiconductor pn junction.
The panel consists of two silicon wafers with different properties. Under the influence of light in one of them there is a lack of electrons, and in the other - their excess. Each plate has copper conductive strips that connect to voltage converters.
An industrial solar panel consists of many laminated photovoltaic cells bonded to each other and mounted on a flexible or rigid substrate.
The efficiency of equipment depends largely on the purity of silicon and the orientation of its crystals. It is these parameters that engineers have been trying to improve in recent decades.The main problem in this case is the high cost of the processes that underlie the purification of silicon and the location of crystals in one direction on the entire panel.
Semiconductors of photoelectric converters can be made not only of silicon, but also of other materials - battery principle it does not change.
Types of Photoelectric Converters
Industrial solar panels are classified by their design features and the type of working photovoltaic layer.
There are these types of batteries by type of device:
- flexible panels;
- rigid modules.
Flexible thin-film panels are gradually occupying a larger niche in the market due to their mounting versatility, because you can install them on most surfaces with a variety of architectural forms.
According to the type of the working photovoltaic layer, solar cells are divided into such varieties:
- Silicon: monocrystalline, polycrystalline, amorphous.
- Tellurium cadmium.
- Based on indium-copper-gallium selenide.
- Based on gallium arsenide.
- Combined and multilayer.
Of interest to the general consumer are not all types of solar panels, but only the first two crystalline subspecies.
Although some other types of panels have high efficiency, but because of the high cost, they are not widely used.
Silicon photovoltaic cells are quite sensitive to heat. The base temperature for measuring power generation is 25 ° C. When it is increased by one degree, the efficiency of the panels decreases by 0.45-0.5%.
Next, solar panels that are of the greatest consumer interest will be examined in detail.
Characteristics of silicon-based panels
Silicon for solar panels is made from quartz powder - crushed quartz crystals. The richest deposits of raw materials are in Western Siberia and the Middle Urals, therefore, the prospects for this area of solar energy are almost limitless.
Even now, crystalline and amorphous silicon panels already occupy more than 80% of the market. Therefore, it is worth considering them in more detail.
Monocrystalline silicon panels
Modern single-crystal silicon wafers (mono-Si) have a uniform dark blue color over the entire surface. For their production, the most pure silicon is used. Monocrystalline photocells among all silicon wafers have the highest price, but also provide the best efficiency.
The high cost of production is due to the difficulty of orienting all silicon crystals in one direction. Due to such physical properties of the working layer, maximum efficiency is ensured only when the sunlight is perpendicular to the surface of the plate.
Monocrystalline batteries require additional equipment that automatically rotates them during the day so that the plane of the panels is as perpendicular to the sun's rays as possible.
Layers of silicon with one-sided oriented crystals are cut from a cylindrical metal bar, so the finished photovoltaic blocks have the form of a square rounded at the corners.
The advantages of single-crystal silicon batteries include:
- High efficiency with a value of 17-25%.
- Compactness - a smaller area of equipment placement per unit of power, in comparison with polycrystalline silicon panels.
- Durability - sufficient power generation efficiency is provided up to 25 years.
There are only two drawbacks to such batteries:
- High price and long payback.
- Sensitivity to pollution. Dust scatters light, therefore, the efficiency of the solar panels coated with it decreases sharply.
Due to the need for direct sunlight, single crystals solar panels are installed mainly in open areas or at heights. The closer the area is to the equator and the more sunny days are in it, the more preferable is the installation of this particular type of photovoltaic cells.
Polycrystalline Solar Panels
Polycrystalline silicon panels (multi-Si) have an uneven blue color due to the versatile orientation of the crystals. The purity of silicon used in their production is slightly lower than that of single-crystal analogues.
The multidirectionality of the crystals provides high efficiency with scattered light - 12-18%. It is lower than in unidirectional crystals, but in cloudy conditions, such panels are more effective.
The heterogeneity of the material also leads to a decrease in the cost of silicon production. The purified metal for polycrystalline solar panels is poured into molds without special tricks.
In production, special techniques are used to form crystals, but their orientation is not controlled. After cooling, silicon is cut into layers and processed according to a special algorithm.
Polycrystalline panels do not require constant orientation towards the sun, therefore, roofs of houses and industrial buildings are actively used for their placement.
The advantages of solar panels with multidirectional crystals include:
- High efficiency in ambient light.
- Possibility of stationary installation on the roofs of buildings.
- Lower cost in comparison with monocrystalline panels.
- Operation duration - the drop in efficiency after 20 years of operation is only 15-20%.
Disadvantages of polycrystalline panels are also available:
- Low efficiency with a value of 12-18%.
- Relative bulkiness - requires more space for installation per unit of power compared to single-crystal counterparts.
Polycrystalline solar panels are gaining an increasing market share among other silicon batteries. This is ensured by wide potential opportunities to reduce the cost of their production. The efficiency of such panels is also increasing annually, rapidly approaching 20% for mass products.
Amorphous Silicon Solar Panels
The mechanism for the production of amorphous silicon solar panels is fundamentally different from the manufacture of crystalline photovoltaic cells. Here, not pure non-metal is used, but its hydride, whose hot vapors are deposited on the substrate.
As a result of this technology, classical crystals are not formed, and production costs are sharply reduced.
At the moment, there are already three generations of panels made of amorphous silicon, in each of which the efficiency is noticeably increased. If the first photovoltaic modules had an efficiency of 4-5%, now the second generation models with an efficiency of 8-9% are massively sold on the market.
Amorphous panels of the latest development have an efficiency of up to 12% and are already beginning to appear on sale, but they are still quite expensive.
Due to the features of this production technology, it is possible to create a silicon layer on both a rigid and flexible substrate. Because of this, amorphous silicon modules are actively used in flexible thin-film solar modules. But options with elastic backing are much more expensive.
The physicochemical structure of amorphous silicon allows maximum absorption of photons of weak scattered light to generate electricity. Therefore, such panels are convenient for use in northern areas with large free areas.
The efficiency of amorphous silicon-based batteries does not decrease even at high temperatures, although they are inferior in this parameter to gallium arsenide panels.
To summarize, we can indicate the following advantages of amorphous solar panels:
- Versatility - the ability to manufacture flexible and thin panels, mounting batteries on any architectural form.
- High efficiency in ambient light.
- Stable work at high temperatures.
- Simplicity and reliability of the design. Such panels practically do not break.
- Preservation of performance in difficult conditions - less performance drop when dusty surface than crystalline analogues
The service life of such photovoltaic cells, starting from the second generation, is 20-25 years with a power drop of 15-20%. The disadvantages of amorphous silicon panels include only the need for larger areas to accommodate equipment of the required power.
Overview of silicon-free devices
Some solar panels made using rare and expensive metals have an efficiency of more than 30%. They are many times more expensive than their silicon counterparts, but nevertheless they have occupied a high-tech trading niche, thanks to their special characteristics.
Rare metal solar panels
There are several types of solar panels made of rare metals, and not all of them have an efficiency higher than that of single-crystal silicon modules.
However, the ability to work in extreme conditions allows manufacturers of such solar panels to produce competitive products and conduct further research.
The main alloys used for the manufacture of photovoltaic cells are cadmium telluride (CdTe), indium copper gallium selenide (CIGS) and indium copper selenide (CIS).
Cadmium is a toxic metal, and indium, gallium and tellurium are quite rare and expensive, so the mass production of solar panels based on them is even theoretically impossible.
The efficiency of such panels is at the level of 25-35%, although in exceptional cases it can reach up to 40%. Previously, they were mainly used in the space industry, but now a new promising direction has appeared.
Due to the stable operation of rare metal solar cells at temperatures of 130-150 ° C, they are used in solar thermal power plants. In this case, the rays of the sun from tens or hundreds of mirrors are concentrated on a small panel, which simultaneously generates electricity and ensures the transfer of thermal energy to the water heat exchanger.
As a result of heating the water, steam forms, which causes the turbine to rotate and generate electricity. Thus, solar energy is converted into electrical energy simultaneously in two ways with maximum efficiency.
Polymer and organic analogues
Photovoltaic modules based on organic and polymer compounds began to be developed only in the last decade, but researchers have already made significant progress. European company shows the most progress Heliatek, which has already equipped several high-rise buildings with organic solar panels.
The thickness of its roll type film construction Heliafilm is only 1 mm.
In the manufacture of polymer panels, substances such as carbon fullerenes, copper phthalocyanine, polyphenylene and others are used. The efficiency of such solar cells already reaches 14-15%, and the cost of production is several times less than crystalline solar panels.
The issue of the period of degradation of the organic working layer is acute. So far, it is not possible to reliably confirm the level of its efficiency after several years of operation.
The benefits of organic solar panels are:
- the possibility of environmentally friendly disposal;
- low cost of production;
- flexible design.
The disadvantages of such photocells include the relatively low efficiency and the lack of reliable information on the periods of stable operation of the panels. It is possible that in 5-10 years all the disadvantages of organic solar cells will disappear, and they will become serious competitors for silicon wafers.
Which solar panel to choose?
The choice of solar panels for country houses at a latitude of 45-60 ° is not difficult. Here, it is worth considering only two options: polycrystalline and single-crystal silicon panels.
If there is a shortage of space, it is better to give preference to more efficient models with one-sided orientation of crystals, with an unlimited area it is recommended to purchase polycrystalline batteries.
Choosing a specific manufacturer, the required capacity and additional equipment is better with the participation of managers of companies involved in the sale and installation of such equipment. You should be aware that the quality and price of photovoltaic modules at the largest manufacturers differ little.
Please note that when ordering a turnkey set of equipment, the cost of the solar panels themselves will be only 30-40% of the total. The payback periods of such projects are 5-10 years, and depend on the level of energy consumption and the possibility of selling surplus electricity to the city network.
Some craftsmen prefer to assemble solar panels with their own hands. On our site there are articles with a detailed description of the manufacturing technology of such panels, their connection and arrangement of heating solar systems.
We advise you to familiarize yourself with:
- How to make a solar battery with your own hands: self-assembly instruction
- Solar heating systems: analysis of heating technology based on solar systems
- Connection diagram for solar panels: to the controller, to the battery and to the serviced systems
Conclusions and useful video on the topic
The presented videos show the operation of various solar panels in real conditions. They will also help to understand the issues of choosing related equipment.
Rules for choosing solar panels and related equipment:
Types of solar panels:
Testing of single-crystal and polycrystalline panels:
For the population and small industrial facilities, there is no real alternative to crystalline silicon panels. But the pace of development of new types of solar panels allows us to hope that soon the energy of the sun will become the main source of electricity in many country houses.
We offer everyone interested in the issue of choosing and using solar panels to leave comments, ask questions and participate in discussions. The contact form is located in the lower block.