Solar Photovoltaic Panels.

September 17, 2021 batteries, cells, module, panels, power, PV, silicon, solar, system, wiring No Comments

PV panels, also known as solar panels, capture the sun’s energy and convert it into electricity. Electricity generated by PV panels is mostly used for powering household appliances and equipment.

Solar panels consist of a series of silicon solar cells covered by a sheet of glass and held together by a metal frame, with wiring and circuitry in and behind the cells to collect the flow of electrical current out of the solar cells. Each solar panel, also referred to as a solar module, is typically about 4 feet by 6 feet in size, and weighs approximately 30 pounds.

Thanks to the development of solar panels, we can harness the energy of an inexhaustible source of power (the sun). Solar panel systems work very simply:

• During the day, solar cells in your solar panels absorb the energy from sunlight.
• Circuits within the cells collect that energy and turn it into direct current (DC) energy.
• The DC electricity is passed through a device called an inverter to convert it to the usable alternating current (AC) electricity that comes out of your wall outlets.
• All of which means you can use that electricity in your home, store it with a solar battery, or send it back to the grid.

Solar panels include one or more PV modules assembled as a pre-wired, field-installable unit.

The most typical PV panel system is the grid-connected system, which as its name indicates, is connected to the national grid. This means that at night, when the solar panels do not work, you can use electricity from the grid.

The second type of PV panel system is the stand alone system, which is not connected to the grid. In this case you can add solar batteries to the system to have electricity when it gets dark. This system can be really convenient in remote areas where there is no alternative for other sources of electricity. Nowadays, thousands of people power up their homes and business with the help of PV panels.

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Solar Photovoltaic Modules.

September 17, 2021 amorphous, cells, concentrators, lenses, module, modules, monocrystalline, multicrystalline, polycrystalline, power, PV, thin-film No Comments

A PV module consists of many PV cells wired in parallel to increase current and in series to produce a higher voltage. 36 cell modules are the industry standard for large power production.

The module is encapsulated with tempered glass (or some other transparent material) on the front surface, and with a protective and waterproof material on the back surface. The edges are sealed for weatherproofing, and there is often an aluminum frame holding everything together in a mountable unit. In the back of the module there is a junction box, or wire leads, providing electrical connections.

Conventionally, PV modules are designed and manufactured for outdoor applications. Thus, they can operate under the sun, rain, and other climate impacts, which make possible the use of PV modules as potential components for external enclosures of buildings.

With the development in the past few decades, various types of PV module technologies are now available in the PV market, but not all these technologies are suitable for the integration or incorporation in building envelopes, since PV modules are traditionally designed mainly for power generation, and their functionalities as envelope elements are generally overlooked.

There are currently four commercial production technologies for PV Modules:

• Single Crystalline. This is the oldest and more expensive production technique, but it's also the most efficient sunlight conversion technology available. Module efficiency averages about 10% to 12%^[*].
• Polycrystalline or Multicrystalline. This has a slightly lower conversion efficiency compared to single crystalline but manufacturing costs are also lower. Module efficiency averages about 10% to 11%^[*].
• String Ribbon. This is a refinement of polycrystalline production, there is less work in production so costs are even lower. Module efficiency averages 7% to 8%^[*].
• Amorphous or Thin Film. Silicon material is vaporized and deposited on glass or stainless steel. The cost is lower than any other method. Module efficiency averages 5% to 7%^[*]

Module electrical connections are made in series to achieve a desired output voltage or in parallel to provide a desired current capability (amperes) of the solar panel or the PV system. The conducting wires that take the current off the modules are sized according to the current rating and may contain silver, copper or other non-magnetic conductive transition metals. Bypass diodes may be incorporated or used externally, in case of partial module shading, to maximize the output of module sections still illuminated.^{[citation needed]}

Some special solar PV modules include concentrators in which light is focused by lenses or mirrors onto smaller cells. This enables the use of cells with a high cost per unit area (such as gallium arsenide) in a cost-effective way.

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Solar Photovoltaic Arrays.

September 17, 2021 array, arrays, modules, panels, photovoltaic, power, PV, solar, system No Comments

A photovoltaic array is the complete power-generating unit, consisting of any number of PV modules and panels.

A photovoltaic array is therefore multiple solar panels electrically wired together to form a much larger PV installation (PV system) called an array, and in general the larger the total surface area of the array, the more solar electricity it will produce.

A PV Array consists of a number of individual PV modules or panels that have been wired together in a series and/or parallel to deliver the voltage and amperage a particular system requires. An array can be as small as a single pair of modules, or large enough to cover acres.

12 volt module is the industry standard for battery charging. Systems processing up to about 2000 watt-hours should be fine at 12 volts. Systems processing 2000 - 7000 watt-hours will function better at 24 volt. Systems running more than 7000 watt-hours should probably be running at 48 volts.

The term solar array is often also used to describe large-scale solar farms, however, it can be used to describe just about any grouping of solar panels.

The size of a photovoltaic array can consist of a few individual PV modules or panels connected together in an urban environment and mounted on a rooftop, or may consist of many hundreds of PV panels interconnected together in a field to supply power for a whole town or neighborhood. The flexibility of the modular photovoltaic array (PV system) allows designers to create solar power systems that can meet a wide variety of electrical needs, no matter how large or small.

It is important to note that photovoltaic panels or modules from different manufacturers should not be mixed together in a single array, even if their power, voltage or current outputs are nominally similar. This is because differences in the solar panels I-V characteristic curves as well as their spectral response are likely to cause additional mismatch losses within the array, thereby reducing its overall efficiency.

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Maintenance of PV Panels.

September 17, 2021 cleaning, inverter, maintenance, panel, panels, power, PV, solar, systems No Comments

PV panels require very little maintenance. Having no moving parts makes them practically maintenance-free and is fairly simple: they just need to be kept respectively clean and to not be overshadowed by trees. it require very little maintenance.

If dust or snow becomes an issue, they need to be rinsed off with warm water. If you don't feel like doing it yourself, you can always contact a window cleaning company and they will do the work.

PV panels are likely to last 25-30 years or more, but the solar panel inverter needs to be replaced after ten to fifteen years. However, it is always good to play it safe and check with your installer to find out what the specific maintenance requirements for your system are, as well as its respective insurance.

Any issues with solar panel performance are usually related to electricity production, which is why most installers recommend monitoring your system’s production. By paying attention to changes in production, you can identify and address issues proactively.

Here, some tips to be considered for maintenance:

Maintenance:

• Keep solar panels out of shade as energy production becomes inefficient when they are kept from absorbing any sunlight.
• Keep an eye on the solar panels and make sure the inverters are flashing green lights. If they are not flashing, you are losing money by no longer compensating for your electricity use.
• Document the day-to-day performance to improve solar panel maintenance. It is important to write down how much energy has been produced at a consistent time every day and make special note of dates where it is very cloudy.
• Monitoring systems help you see how much you are benefiting the environment and how much CO2 you are emitting into the atmosphere. They can also help you know how much you could benefit from the feed-in tariff scheme.
• You can also see information about your solar panels servicing on a wall-mounted display when you are at home.
• If you have no time in cleaning solar panels, you can install automated cleaners that work like sprinkler systems or even schedule appointments with solar panel cleaning companies.
• Luckily, because solar panels have no moving parts that could be affected by rust or break down, solar power maintenance may not be needed.

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Solar Photovoltaic Systems.

September 17, 2021 battery, charge controller, electrical, electricity, inverter, mechanical, modules, mounting, overcurrent, panels, photovoltaic, PV, solar, surge protection, systems, tracking, utility meter, wiring No Comments

Solar Photovoltaic Systems, is composed of one or more solar panels combined with an inverter and other electrical and mechanical hardware that use energy from the Sun to generate electricity.

PV systems can vary greatly in size from small rooftop or portable systems to massive utility-scale generation plants. Although PV systems can operate by themselves as off-grid PV systems.

A complete system includes different components that should be selected taking into consideration your individual needs, site location, climate and expectations. It consists of an arrangement of several components, including:

• PV Modules. To absorb and convert sunlight into electricity.
• Inverter. Converts DC power into standard AC power for use in the home, synchronizing with utility power whenever the electrical grid is distributing electricity.
• Battery, stores energy when there is an excess coming in and distribute it back out when there is a demand. Solar PV panels continues to re-charge batteries each day to maintain battery charge.
• Utility Meter. Utility power is automatically provided at night and during the day when the demand exceeds your solar electric power production. The utility meter actually spins backwards when solar power production exceeds house demand, allowing you to credit any excess electricity against future utility bills.
• Charge Controller. Prevents battery overcharging and prolongs the battery life of your PV system.

In addition mounting, wiring, overcurrent, surge protection and disconnect devices, and other power processing equipment.

It may also use a solar tracking system to improve the system's overall performance and include an integrated battery solution, as prices for storage devices are expected to decline.

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Newer Semiconductor Materials.

September 16, 2021 bandgap, cell, cells, DSSC, dye, inorganic, nanoparticles, OPV, organic, perovskite, polymer, PPV, PV, quantum dots, solar, thin-film, titanium dioxide No Comments

Newer Materials.

1. Dye-Sensitized.

Another type of solar cell material is a small molecule dye, such as a ruthenium metalorganic dye, that can absorb a broad range of the visible region of sunlight. An inorganic mesoporous nanoparticle layer, usually titanium dioxide, increases the area for light absorption. Solar cells using these materials can be made using solution processing, making them inexpensive to fabricate.

Dye-sensitized solar cells (DSSCs) belong to the group of thin-film solar cells which have been under extensive research for more than two decades due to their low cost, simple preparation methodology, low toxicity and ease of production.

Still, there is lot of scope for the replacement of current DSSC materials due to their high cost, less abundance, and long-term stability.

2. Organic/Polymer.

Semiconducting polymers such as polyphenylene vinylene (PPV) and small organic small molecules such as phthalocyanines, polyacenes, and squarenes are also used in solar cells. These highly conjugated organic molecules have a broad absorption in the visible and near infrared region. These materials are deposited as thin films either by vacuum deposition methods or solution processing, and solar cells using these materials are usually thin and flexible. However, the efficiency of these cells is still low, just a little more than 10%, hence they have not been commercialized yet.

OPV cells are currently only about half as efficient as crystalline silicon cells and have shorter operating lifetimes, but could be less expensive to manufacture in high volumes.

They can also be applied to a variety of supporting materials, such as flexible plastic, making OPV able to serve a wide variety of uses.

3. Perovskite.

Perovskite cells are generally hybrid organic-inorganic lead or tin-halide materials, such as methylammonium lead halide. The cells are built with layers of materials that are printed, coated, or vacuum-deposited onto an underlying support layer, known as the substrate.

These materials can be solution-processed, hence enable inexpensive and simple fabrication. They are typically easy to assemble and can reach efficiencies similar to crystalline silicon.In the lab, perovskite solar cell efficiencies have improved faster than any other PV material, from 3% in 2009 to over 25% in 2020.

One of the key advantages of these materials is their ability to absorb sunlight across the entire visible spectrum.

To be commercially viable, perovskite PV cells have to become stable enough to survive 20 years outdoors, so researchers are working on making them more durable and developing large-scale, low-cost manufacturing techniques.

4. Quantum dots.

Nanoparticles, a few nm in size, called quantum dots are another type of emerging materials used in solar cells that conduct electricity through tiny particles of different semiconductor materials just a few nanometers wide. They are low bandgap semiconductor materials such as CdS, CdSe, and PbS. Their bandgaps can be tuned over a wide range by changing the size of the particles.

Quantum dots provide a new way to process semiconductor materials, but it is difficult to create an electrical connection between them, so they’re currently not very efficient. However, they are easy to make into solar cells. They can be deposited onto a substrate using a spin-coat method, a spray, or roll-to-roll printers like the ones used to print newspapers.

Many common materials used for fabricating quantum dots such as Cd and Pb are considered toxic, hence other alternative materials such as copper indium selenide are being developed.

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Thin-Film Solar Cell.

September 16, 2021 a-Si, amorphous, Cadmium Telluride, CdTe, cell, cells, CIGS, Copper Indium Gallium Selenide, GaAs, Gallium Arsenide, PV, silicon, solar, thin-film No Comments

Thin-Film.

Thin-film are cells that have light-absorbing layers about 350 times smaller than the standard silicon. Because of their narrow design and the efficient semiconductor built into their cells, thin-film solar cells are the lightest PV cell you can find while still maintaining strong durability.

The cell is made by depositing one or more thin layers of PV material on a supporting material such as glass, plastic, or metal.

Thin-film solar panels are typically made with one of the following four technologies:

• Cadmium Telluride (CdTe) – The most widely used thin-film technology, CdTe holds roughly 50% of the market share for thin-film solar panels. CdTe contains significant amounts of Cadmium – an element with relative toxicity – so this is a factor of consideration. First Solar is the top innovator and seller in this space.

• Amorphous Silicon (a-Si) – The second most popular thin-film option after CdTe, a-Si is the most similar technology to that of a standard silicon wafer panel. a-Si is a much better option than its counterparts (CdTe, CIGS) in terms of toxicity and durability, but it is less efficient and is typically used for small load requirements like consumer electronics. The quest for scale is always a hindrance for a-Si.

• Copper Indium Gallium Selenide (CIGS) – Laboratory CIGS cells have reached efficiency highs of 22.4%. However, these performance metrics are not yet possible at scale. The primary manufacturer of CIGS cells was Solyndra (which went bankrupt in 2011). Today, the leader is Solar Frontier. MiaSolé also manufactures CIGS panels in the U.S. and China.

• Gallium Arsenide (GaAs) – A very expensive technology, GaAs holds a world record 28.9% efficiency for all single-junction solar cells. GaAs is primarily used on spacecrafts and is meant for versatile, mass-scale installments of PV energy in unusual environments.

It is used in building-integrated photovoltaics and as semi-transparent, photovoltaic glazing material that can be laminated onto windows.

Thin film solar panels are the cheapest, but have the lowest efficiency rating and require a lot of space to meet your energy needs

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Solar Photovoltaic Cell (also called a solar cell).

September 15, 2021 amorphous, arrays, cell, cells, crystalline, panels, photovoltaic, polycrystalline, PV, semiconductor, silicon No Comments

Solar cell, also called photovoltaic (PV) cell, any device that directly converts the energy of light into electrical energy through the photovoltaic effect. The PV cell is composed of semiconductor material. Unlike batteries or fuel cells, solar cells do not utilize chemical reactions or require fuel to produce electric power, and, unlike electric generators, they do not have any moving parts.

When the semiconductor is exposed to light, it absorbs the light’s energy and transfers it to negatively charged particles in the material called electrons. This extra energy allows the electrons to flow through the material as an electrical current.

The efficiency of a PV cell is simply the amount of electrical power coming out of the cell compared to the energy from the light shining on it, which indicates how effective the cell is at converting energy from one form to the other.

The overwhelming majority of solar cells are fabricated from silicon, with increasing efficiency and lowering cost as the materials range from amorphous (noncrystalline) to polycrystalline to crystalline (single crystal) silicon forms.

Structure and operation.

Light enters the device through an optical coating, or antireflection layer, that minimizes the loss of light by reflection; it effectively traps the light falling on the solar cell by promoting its transmission to the energy-conversion layers below. The antireflection layer is typically an oxide of silicon, tantalum, or titanium that is formed on the cell surface by spin-coating or a vacuum deposition technique.

The three energy-conversion layers below the antireflection layer are the top junction layer, the absorber layer, which constitutes the core of the device, and the back junction layer. Two additional electrical contact layers are needed to carry the electric current out to an external load and back into the cell, thus completing an electric circuit.

The electrical contact layer on the face of the cell where light enters is generally present in some grid pattern and is composed of a good conductor such as a metal. Since metal blocks light, the grid lines are as thin and widely spaced as is possible without impairing collection of the current produced by the cell. The back electrical contact layer has no such diametrically opposed restrictions. It need simply function as an electrical contact and thus covers the entire back surface of the cell structure. Because the back layer also must be a very good electrical conductor, it is always made of metal.

The amount of electricity produced from PV cells depends on the characteristics (such as intensity and wavelengths) of the light available and multiple performance attributes of the cell.

Solar cells can be arranged into large groupings called arrays. These arrays, composed of many thousands of individual cells, can function as central electric power stations, converting sunlight into electrical energy for distribution to industrial, commercial, and residential users.

Solar cells in much smaller configurations, commonly referred to as solar cell panels or simply solar panels, have been installed by homeowners on their rooftops to replace or augment their conventional electric supply. Solar cell panels also are used to provide electric power in many remote terrestrial locations where conventional electric power sources are either unavailable or prohibitively expensive to install.

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Photovoltaic Solar Technology.

September 15, 2021 arrays, cell, cells, electricity, modules, panel, panels, photovoltaic, polycrystalline, power, PV, silicon, systems No Comments

Solar cells, also called photovoltaic cells, convert sunlight directly into electricity.  Photovoltaics (often shortened as PV) gets its name from the process of converting light (photons) to electricity (voltage), which is called the photovoltaic effect. This material, usually made of silicon but potentially other polycrystalline thin films, generates a direct current when sunlight hits the panel.

A single PV device is known as a cell. An individual PV cell is usually small, typically producing about 1 or 2 watts of power. To boost the power output of PV cells, they are connected together in chains to form larger units known as modules or panels. Modules can be used individually, or several can be connected to form arrays.

Commercially available PV panels are up to 22.5% efficient at converting sunlight into electricity in optimal conditions, but even in partly cloudy weather, they can operate at 80% of their maximum output.

PV systems may or may not be connected to the electric transmission grid:

• PV systems linked to the transmission grid can supplement utilities energy supply during daylight hours, which normally include the peak energy demand periods.
• Independent PV cells can power a variety of individual items, from personal calculators and streetlights to water pumps on ranches and remote settlements far from power lines.

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