Photovoltaic solar panels absorb sunlight as a source of energy to generate electricity. The photovoltaic (PV) module is a connected packet connected to a photovoltaic solar cell that is usually 6x10 in size. The photovoltaic module is a photovoltaic arrangement of photovoltaic systems that produce and supply solar electricity in commercial and residential applications.
Each module is rated by DC output power under standard test conditions (STC), and typically ranges from 100 to 365 Watt (W). The efficiency of a module determines the area of ​​a module given the same rated output - an efficient 230% 230 W module will have twice the area of ​​an efficient 230 W module 16%. There are several commercially available solar modules that exceed the efficiency of 24%
A solar module can produce only limited power; most installations contain many modules. Photovoltaic systems typically include photovoltaic module arrays, inverters, battery packs for storage, interconnection cables, and optionally sun tracking mechanisms.
The most common application of solar panels is the solar water heating system.
The price of solar power continues to fall so that in many countries it is cheaper than ordinary fossil fuel electricity from the power grid, a phenomenon known as grid parity.
Video Solar panel
Theory and construction
Photovoltaic modules use light energy (photons) from the Sun to generate electricity through photovoltaic effects. The majority of modules use crystalline silicon wafer cells or thin film cells. Structural members (load carriers) of a module can be either upper or back layers. The cells should also be protected from mechanical damage and moisture. Most of the rigid, but semi-flexible modules based on thin-film cells are also available. The cells must be electrically connected in series, one to the other. Externally, most photovoltaic modules use MC4 connector types to facilitate easy weatherproof connections throughout the system.
The electrical connection module is made in series to achieve the desired output voltage or in parallel to provide the desired current capability. The conductor cable that takes current from the module may contain silver, copper or other non-magnetic conductive transition metal. Bypass diodes can be inserted or used externally, in case of partial shading modules, to maximize the output of the module section is still illuminated.
Some special solar PV modules include concentrators in which light is focused by the lens or mirror into smaller cells. This allows the use of cells at a cost per unit area (such as gallium arsenide) in a cost-effective way.
The solar panels also use metal frames which consist of rack components, brackets, reflector shapes, and troughs to better support panel structures.
Maps Solar panel
Efficiency
Depending on construction, photovoltaic modules can generate electricity from a wide range of light frequencies, but usually can not cover the entire solar range (specifically, ultraviolet, infrared and low light or diffuse). Therefore, a lot of solar energy is wasted by solar modules, and they can provide much higher efficiency when illuminated with monochromatic light. Therefore, another design concept is to break the light into six to eight different wavelength ranges that will produce different colors of light, and direct the beams to different cells set to that range. It has been projected to increase efficiency by up to 50%.
Scientists from Spectrolab, a Boeing subsidiary, have reported the development of multi-junction solar cells with efficiencies of over 40%, a new world record for photovoltaic solar cells. Spectrolab scientists also predict that concentrator solar cells can achieve efficiencies of more than 45% or even 50% in the future, with theoretical efficiency being about 58% in cells with more than three intersections.
Currently, the best achieved sunlight conversion rate (solar module efficiency) is approximately 21.5% in new commercial products that are typically lower than their cell efficiency in isolation. The most efficient mass-produced solar module has a power density rating of up to 175 W/m 2 (16.22 W/feet 2 ).
Research by Imperial College, London has shown that the efficiency of solar panels can be enhanced by studying the surface of light-receiving semiconductors with aluminum nanocylinders similar to those in the Lego block. The scattered light then runs along a longer path in the semiconductor which means that more photons can be absorbed and converted into currents. Although these nanocylinders have been used previously (aluminum is preceded by gold and silver), light scattering occurs in the near infrared region and visible light absorbs strongly. Aluminum was found to have absorbed the ultraviolet part of the spectrum, while the visible and near infrared spectral parts were found scattered by the aluminum surface. This, according to the study, can significantly reduce costs and increase efficiency because aluminum is more abundant and cheaper than gold and silver. The study also notes that the increase in current making thin film solar panels is technically feasible without "sacrificing power conversion efficiency, thus reducing material consumption".
- The efficiency of solar panels can be calculated with the MPP (maximum power point) value of solar panels
- Solar inverters convert DC power into AC power by performing the MPPT process: the solar inverter sample outputs Power (curve IV) of the solar cell and implements proper resistance (load) to the solar cell to obtain maximum power.
- MPP (Maximum power point) of the solar panel consists of MPP (V mpp) and MPP current voltage (I mpp): it is the capacity of the solar panel and the higher value can make MPP higher.
The micro-inverted solar panel is a parallel cable, which produces more output than the normal panel connected in series with the output of the series determined by the lowest performing panel (this is known as the "Christmas light effect"). The micro inverter works independently so each panel contributes the maximum possible output given the available sunlight.
Technology
Most current solar modules are produced from crystalline silicon solar cells (c-Si) made from multicrystalline silicon and monocrystalline. In 2013, crystalline silicon accounts for more than 90 percent of PV production worldwide, while the rest of the market as a whole consists of thin film technology using cadmium telluride, CIGS and amorphous silicon
Appeared, third generation solar technology uses sophisticated thin film cells. They result in a relatively high conversion efficiency for low cost compared to other solar technologies. Also, multimeter cells with high cost, high efficiency, and very dense are preferably used in solar panels on the spacecraft, as they offer the highest ratio of the power generated per kilogram that is lifted into space. MJ cells are semiconducting compounds and are made of gallium arsenide (GaAs) and other semiconductor materials. Another emerging PV technology using MJ-cells is the concentrator photovoltaic (CPV).
Thin film
In rigid thin film modules, cells and modules are produced on the same production line. Cells are made on glass or superstrate substrates, and electrical connections are made in situ , called "monolithic integration". Substrate or superstrate laminated with encapsulation to the front or back sheet, usually another sheet of glass. The major cell technologies in this category are CdTe, or a-Si, or Si-Si uc-Si tandem, or CIGS (or variants). Amorphous silicon has a sunlight conversion rate of 6-12%
Flexible flexible cell cells and modules are made on the same production line by storing photoactive layers and other layers required on flexible substrates. If the substrate is an insulator (eg polyester film or polyimide) then monolithic integration can be used. If the conductor then another technique for electrical connection should be used. The cells are assembled into modules by coating them onto a transparent colored fluoropolymer on the front side (usually ETFE or FEP) and a polymer suitable for binding to the final substrate on the other side.
Smart solar module
Some companies began to embed electronic devices into PV modules. It enables tracking of maximum power point (MPPT) for each module individually, and measurement of performance data for error monitoring and detection at the module level. Some of these solutions utilize a power optimizer, a DC-to-DC converter technology developed to maximize the power harvest of a solar photovoltaic system. In about 2010, such electronics can also compensate for the shadow effect, where shadows fall in the module section causing the electrical output of one or more cell strings in the module to fall to zero, but not having the output of all modules dropping to zero.
Performance and degradation
Module performance is generally assessed under standard test conditions (STC): 1000 W/m 2 radiation, solar spectrum from AM 1.5 and module temperature at 25 Â ° C.
The electrical characteristics include nominal power (P MAX , measured in W), open circuit voltage (V OC ), short-circuit current (I SC , measured in amperes), maximum electric voltage (V MPP ), maximum power current (I MPP ), peak power, (peak wattage, W p ), and module efficiency (%).
Nominal voltage refers to the battery voltage that the module is best suited for charging; this is the residual term of the days when solar modules were only used to charge the battery. The actual output voltage of the module changes when the lighting conditions, temperature and load change, so there is never a special voltage in which the module operates. The nominal voltage allows the user, at a glance, to ensure the module is compatible with the given system.
Open circuit voltage or V OC is the maximum voltage the module can generate when it is not connected to the circuit or electrical system. V OC can be measured with a voltmeter directly on the illuminated module terminal or on the disconnected cable.
The peak power rating, W p , is the maximum output under standard test conditions (not the maximum possible output). Typical modules, which can measure about 1 m² or 3 ft 3 in 7 inches, will be rated from as low as 75 W to as high as 350 W, depending on efficiency. At the time of the test, the binned test module complies with their test results, and the typical manufacturer may rate their modules in 5 W increments, and assign values ​​to/- 3%,/- 5%, 3/-0% or 5/-0%.
The ability of solar modules to withstand damage caused by rain, hail, heavy snow loads, and heat and cold cycles varies by manufacturer, although most of the solar panels in the US market are UL registered, meaning they have gone through testing to withstand hail. Many crystalline silicon module manufacturers offer limited guarantees that guarantee electricity production for 10 years at 90% of measured power output and 25 years at 80%. Installations intended to withstand extreme environments such as heavy hail or heavy snow will require extra protection in the form of steep installations, sturdy frames and stronger glass.
The potential of induced degradation (also called PID) is the potential performance degradation caused in the crystalline photovoltaic module, caused by so-called wild currents. This effect can cause a power loss of up to 30%.
The biggest challenge to photovoltaic technology is said to be the purchase price per watt of electricity generated, new materials and manufacturing techniques continue to increase prices for power performance. The problem lies in the enormous activation energy that must be overcome for photons to generate electrons for the purpose of harvesting. Advances in photovoltaic technology have brought the process of "doping" the silicon substrate to lower the activation energy thus making the panel more efficient in converting photons into electrons that can be taken.
Chemicals such as Boron (p-type) are applied to semiconductor crystals to create donor and acceptor energy levels much closer to the valence band and the conductor. Thus, the addition of Boron impurities allows the activation energy to be reduced by 20-fold from 1.12 eV to 0.05 eV. Since the potential difference (E B ) is very low, Boron is able to ionize thermally at room temperature. This allows the carrier of free energy in the conduction and valence bands to enable the conversion of photons into larger electrons.
Maintenance
The efficiency of solar panel conversion, usually in the 20% range, is reduced by dust, dust, pollen, and other particles accumulated in solar panels. "Dirty solar panels can reduce their power capability by up to 30% in dust/pollen or desert areas," says Seamus Curran, professor of physics at the University of Houston and director of the Institute for NanoEnergy, specializing in the design, engineering and assembly of structures nano.
Paying for cleaned solar panels is often not a good investment; researchers found the panels that have not been cleaned, or rained, for 145 days during the dry season in California, lost only 7.4% of their efficiency. Overall, for a typical 5 kW residential solar system, washing the panels in mid-summer will translate into just $ 20 profit in electricity production until the summer dry season ends - about 2 ½ months. For larger commercial roof systems, greater financial losses but still rare enough to ensure the cost of washing the panels. On average, panels lose slightly less than 0.05% of their overall efficiency per day.
Recycle
Most solar modules can be recycled including up to 95% of certain semiconductor materials or glass as well as large quantities of non-ferrous metals and metals. Some private companies and nonprofit organizations are currently involved in the recovery and recycling operations for the final module of its lifetime.
The chances of recycling depend on the type of technology used in the module:
- Silicon-based modules: aluminum frames and connection boxes unloaded manually at the beginning of the process. The modules are then destroyed at different factories and fractions separated - glass, plastic and metal. It is possible to recover more than 80% of incoming weight. This process can be done by flat glass recyclers because the morphology and composition of PV modules are similar to flat glasses used in the building and automotive industry. Glass taken for example, ready to be accepted by foam glass and glass insulation industry.
- Non-silicon-based modules: they require special recycling technologies such as the use of chemical baths to separate different semiconductor materials. For the cadmium telluride module, the recycling process begins by destroying the module and then separating the different fractions. The recycling process is designed to recover up to 90% of the glass and 95% of the semiconducting material contained. Several commercial-scale recycling facilities have been made in recent years by private companies. For aluminum flat plate reflectors: reflector trendiness has been brought about by their fabrication using a thin layer (about 0.016 mm to 0.024 mm) of Aluminum coating present in non-recycled plastic food packages.
Since 2010, there is an annual European conference that brings together producers, recyclers, and researchers to see the future of PV module recycling.
Production
In 2010, a 15.9 GW solar PV system installation was completed, with a survey of PV solar prices and market research firm PVinsights reporting a 117.8% growth in solar PV installation on a year-on-year basis.
With more than 100% year-over-year growth in PV system installations, PV module makers dramatically increased their solar module shipments by 2010. They are actively expanding their capacity and transforming themselves into gigawatt GW players. According to PVinsights, five of the ten PV module companies in 2010 are GW players. Suntech, First Solar, Sharp, Yingli and Trina Solar are GW manufacturers now, and most of them double their shipments by 2010.
The basis for producing solar panels revolves around the use of silicon cells. These silicon cells are usually 10-20% efficient in converting sunlight into electricity, with the new production model now exceeding 22%.
In order for solar panels to be more efficient, researchers around the world have tried to develop new technologies to make solar panels more effective in converting sunlight into energy.
By 2014, the world's four largest solar module manufacturers in terms of capacity delivered during calendar year 2014 are Yingli, Trina Solar, Sharp Solar, and Canadian Solar.
Price
The average price information is divided into three price categories: those who buy small quantities (all module sizes in kilowatts range each year), medium-range buyers (typically up to 10 MWp per year), and large quantities of buyers (self-explanatory - and with access to the lowest price). In the long run there is clearly a systematic reduction in the price of cells and modules. For example, in 2012 it is estimated that the quantity cost per watt is about US $ 0.60, which is 250 times lower than the cost in 1970 of US $ 150. A study 2015 shows price/kWh down 10% per year since 1980 , and predicts that diesel fuel can contribute 20% of total electricity consumption by 2030, while the International Energy Agency estimates 16% by 2050.
The cost of real world energy production depends heavily on local weather conditions. In cloudy countries such as the United Kingdom, the cost per kWh produced is higher than in brighter countries such as Spain.
Following the RMI element, Balance-of-System (BoS), this is a non-module non-module non-module solar module (such as wiring, converters, racking systems and various components) making up about half of the total installation cost.
For a merchant solar power plant, where electricity is sold to the electricity transmission network, the cost of solar energy should be in line with wholesale electricity prices. This point is sometimes called 'wholesale grid parity' or 'busbar parity'.
Some photovoltaic systems, such as roof installations, can supply power directly to power users. In this case, installation can be competitive when the output cost matches the price at which the user pays for electricity consumption. This situation is sometimes called 'retail box parity', 'socket similarity' or 'dynamic grid parity'. Research conducted by UN-Energy in 2012 shows bright areas of the country with high electricity prices, such as Italy, Spain and Australia, and regions using diesel generators, have reached the parity of the retail grid.
According to India's latest solar market research, 2018 by Loom Solar "India's premium solar brand store" , the average solar panel price range is Rs. 30 to 45 per watt , and most solar panel requests are 1 kW to 10 kW for home, office and commercial space.
Install and track
The photovoltaic systems installed in the ground are usually large, utility-scale solar power plants. Their solar modules are held in place by shelves or frames attached to ground-based mounting support. Land-based installation support includes:
- Pole mounts, which are pushed directly to the ground or pinned on the concrete.
- Foundation mounts, such as concrete slabs or footing poured
- Rinse footing, such as concrete or steel laden boulders to secure the solar module system in position and does not require soil penetration. This type of mounting system is perfect for sites where excavation is not possible such as enclosed landfills and simplifies the decommissioning or relocation of solar module systems.
The roof-mounted solar system consists of a solar module held by a shelf or framework mounted on a roof-mounted mounting support. Root-based installation support includes:
- The mountain pillar, which is attached directly to the roof structure and can use additional rails to install the modular shelf or frame.
- Rinse footing, such as heavy-duty concrete or steel chunks to secure the panel system in position and does not require through penetration. This mounting method allows for the decommissioning or relocation of solar panel systems without any adverse effects on the roof structure.
- All cables connecting solar modules adjacent to energy harvesting equipment must be installed in accordance with local electrical codes and must be run in a channel suitable for climatic conditions
The solar tracker increases the amount of energy produced per module at the cost of mechanical complexity and maintenance requirements. They sense the direction of the Sun and tilt or rotate the modules necessary for maximum exposure to light. Alternatively, the rack keeps the module while the sun moves across the sky. The shelf fixed the angle when the module is on hold. A slope angle equivalent to the latitude of the installation is common. Most of the fixed shelves are mounted on poles above the ground. Panels facing West or East can provide slightly lower energy, but balance the supply, and can provide more power during peak demand.
Standard
Standards commonly used in photovoltaic modules:
- IEC 61215 (crystalline silicon performance), 61646 (thin film performance) and 61730 (all modules, security)
- ISO 9488 Solar energy - Vocabulary.
- UL 1703 from Underwriters Laboratories
- UL 1741 from Underwriters Laboratories
- UL 2703 from Underwriters Laboratories
- CE mark
- Series of Electrical Safety Tester (EST) (EST-460, EST-22V, EST-22H, EST-110).
Apps
There are many practical applications for the use of solar panels or photovoltaics. First can be used in agriculture as a source of electricity for irrigation. In the solar panels health care can be used to cool the medical supply. It can also be used for infrastructure. The PV modules are used in photovoltaic systems and include a wide range of electrical devices:
- Photovoltaic power generation
- The roof solar PV system
- standalone PV system
- Solar hybrid power system
- Photovoltaics are concentrated
- The solar plane
- Solar-pumped laser
- The solar vehicle
- Solar panels in spacecraft and space stations
Limitations
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- Pollution and Energy in Production
Solar panels have become a well known method for generating clean emissions free electricity. However, it only produces direct electrical current (DC), which is not a commonly used equipment. Solar photovoltaic systems (solar PV systems) are often made solar PV panels (modules) and inverters (convert DC to AC). The solar PV panels are primarily made of photovoltaic solar cells, which have no fundamental difference with materials for making computer chips. The process of producing solar PV cells (computer chips) is energy intensive and involves highly toxic and environmental toxic chemicals. There are several solar PV manufacturing factories around the world that produce PV modules with energy produced from PV. This measure greatly reduces the carbon footprint during the manufacturing process. Managing chemicals used in the manufacturing process is subject to local factory laws and regulations.
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- Impact on Electrical Network
With the increasing levels of roof photovoltaic systems, the flow of energy becomes 2 directions. When there are more local generations than consumption, electricity is exported to the grid. However, the power grid is traditionally not designed to handle two-way energy transfers. Therefore, some technical problems may occur. For example in Queensland Australia, there are more than 30% of households with roofing PV by the end of 2017. The very popular California duck curve appears very often for many communities from 2015 onwards. The problem of excess voltage can come out because electricity is flowing from this PV household back to the network. There are solutions to manage more voltage problems, such as setting the power factor of PV inverter, new voltage and energy control equipment at power distributor level, re-conductor power cable, demand side management, etc. There are often limitations and costs associated with this solution.
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- Implications for Electricity Billing and Energy Investment
There is no silver bullet in electricity or energy demand and bill management, because the customer (site) has a different specific situation, eg. different comfort/convenience requirements, different electricity rates, or different usage patterns. Electricity rates may have several elements, such as daily access and meter costs, energy costs (based on kWh, MWh) or peak demand costs (eg prices for the highest 30min energy consumption in a month). PV is a promising choice to reduce energy costs when electricity prices are high and continue to rise, as in Australia and Germany. But for sites with top peak demand costs in place, PV may be less attractive if peak demands mostly occur in the afternoon until late afternoon, for example housing communities. Overall, energy investment is largely an economical and better decision to make investment decisions based on systematic evaluation of options in operational improvement, energy efficiency, onsite generation and energy storage.
Gallery
See also
References
Source of the article : Wikipedia
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