Photovoltaic Cells

December 21, 2009 By: Admin Category: Solar Cells

Glitter-sized Solar Photovoltaics Produce Competitive Results

Adventures in microsolar supported by microelectronics and MEMS techniques

Sandia National Laboratories scientists have developed tiny glitter-sized photovoltaic cells that could revolutionize the way solar energy is collected and used.

The tiny cells could turn a person into a walking solar battery charger if they were fastened to flexible substrates molded around unusual shapes, such as clothing.

The solar particles, fabricated of crystalline silicon, hold the potential for a variety of new applications. They are expected eventually to be less expensive and have greater efficiencies than current photovoltaic collectors that are pieced together with 6-inch- square solar wafers.

The cells are fabricated using microelectronic and microelectromechanical systems (MEMS) techniques common to today’s electronic foundries.

Sandia lead investigator Greg Nielson said the research team has identified more than 20 benefits of scale for its microphotovoltaic cells. These include new applications, improved performance, potential for reduced costs and higher efficiencies.

“Eventually units could be mass-produced and wrapped around unusual shapes for building-integrated solar, tents and maybe even clothing,” he said. This would make it possible for hunters, hikers or military personnel in the field to recharge batteries for phones, cameras and other electronic devices as they walk or rest.

Even better, such microengineered panels could have circuits imprinted that would help perform other functions customarily left to large-scale construction with its attendant need for field construction design and permits.

Said Sandia field engineer Vipin Gupta, “Photovoltaic modules made from these microsized cells for the rooftops of homes and warehouses could have intelligent controls, inverters and even storage built in at the chip level. Such an integrated module could greatly simplify the cumbersome design, bid, permit and grid integration process that our solar technical assistance teams see in the field all the time.”

For large-scale power generation, said Sandia researcher Murat Okandan, “One of the biggest scale benefits is a significant reduction in manufacturing and installation costs compared with current PV techniques.”

Part of the potential cost reduction comes about because microcells require relatively little material to form well-controlled and highly efficient devices.

From 14 to 20 micrometers thick (a human hair is approximately 70 micrometers thick), they are 10 times thinner than conventional 6-inch-by-6-inch brick-sized cells, yet perform at about the same efficiency.

100 times less silicon generates same amount of electricity

“So they use 100 times less silicon to generate the same amount of electricity,” said Okandan. “Since they are much smaller and have fewer mechanical deformations for a given environment than the conventional cells, they may also be more reliable over the long term.”

Another manufacturing convenience is that the cells, because they are only hundreds of micrometers in diameter, can be fabricated from commercial wafers of any size, including today’s 300-millimeter (12-inch) diameter wafers and future 450-millimeter (18-inch) wafers. Further, if one cell proves defective in manufacture, the rest still can be harvested, while if a brick-sized unit goes bad, the entire wafer may be unusable. Also, brick-sized units fabricated larger than the conventional 6-inch-by-6-inch cross section to take advantage of larger wafer size would require thicker power lines to harvest the increased power, creating more cost and possibly shading the wafer. That problem does not exist with the small-cell approach and its individualized wiring.

Other unique features are available because the cells are so small. “The shade tolerance of our units to overhead obstructions is better than conventional PV panels,” said Nielson, “because portions of our units not in shade will keep sending out electricity where a partially shaded conventional panel may turn off entirely.”

Because flexible substrates can be easily fabricated, high-efficiency PV for ubiquitous solar power becomes more feasible, said Okandan.

A commercial move to microscale PV cells would be a dramatic change from conventional silicon PV modules composed of arrays of 6-inch-by-6-inch wafers. However, by bringing in techniques normally used in MEMS, electronics and the light-emitting diode (LED) industries (for additional work involving gallium arsenide instead of silicon), the change to small cells should be relatively straightforward, Gupta said.

Each cell is formed on silicon wafers, etched and then released inexpensively in hexagonal shapes, with electrical contacts prefabricated on each piece, by borrowing techniques from integrated circuits and MEMS.

Offering a run for their money to conventional large wafers of crystalline silicon, electricity presently can be harvested from the Sandia-created cells with 14.9 percent efficiency. Off-the-shelf commercial modules range from 13 to 20 percent efficient.

A widely used commercial tool called a pick-and-place machine — the current standard for the mass assembly of electronics — can place up to 130,000 pieces of glitter per hour at electrical contact points preestablished on the substrate; the placement takes place at cooler temperatures. The cost is approximately one-tenth of a cent per piece with the number of cells per module determined by the level of optical concentration and the size of the die, likely to be in the 10,000 to 50,000 cell per square meter range. An alternate technology, still at the lab-bench stage, involves self-assembly of the parts at even lower costs.

Solar concentrators — low-cost, prefabricated, optically efficient microlens arrays — can be placed directly over each glitter-sized cell to increase the number of photons arriving to be converted via the photovoltaic effect into electrons. The small cell size means that cheaper and more efficient short focal length microlens arrays can be fabricated for this purpose.

High-voltage output is possible directly from the modules because of the large number of cells in the array. This should reduce costs associated with wiring, due to reduced resistive losses at higher voltages.

Other possible applications for the technology include satellites and remote sensing.

The project combines expertise from Sandia’s Microsystems Center; Photovoltaics and Grid Integration Group; the Materials, Devices, and Energy Technologies Group; and the National Renewable Energy Lab’s Concentrating Photovoltaics Group.

Involved in the process, in addition to Nielson, Okandan and Gupta, are Jose Luis Cruz-Campa, Paul Resnick, Tammy Pluym, Peggy Clews, Carlos Sanchez, Bill Sweatt, Tony Lentine, Anton Filatov, Mike Sinclair, Mark Overberg, Jeff Nelson, Jennifer Granata, Craig Carmignani, Rick Kemp, Connie Stewart, Jonathan Wierer,

George Wang, Jerry Simmons, Jason Strauch, Judith Lavin and Mark Wanlass (NREL).

The work is supported by DOE’s Solar Energy Technology Program and Sandia’s Laboratory Directed Research & Development program, and has been presented at four technical conferences this year.

The ability of light to produce electrons, and thus electricity, has been known for more than a hundred years.

[Via]

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Solar Technologies

November 27, 2009 By: Admin Category: General

New Solar Technology

Solar technologies is now highly developed, with some progress is being developed to be used every day.

Below 10 Solar Technologies to note:

1. Water Heating Solar Panel: Pyron Solar Triad uses a special design, short focal-length, lens in the acrylic concentration to reflect and accept the light, effectively concentrate 6.500 solar power in the form of a small light. The second lens capture light and focus on PV cells. According to related companies, HE Optics System produces 800 times more energy than the silicon solar cells.
2. Home Solar to Hydrogen Storage: An MIT professor Daniel Nocera, build a company this year to market a technology that can split water and store solar energy. The key of this company is to achieve a breakthrough solar energy to make solar power cheaper.
   “The idea is to use solar panels to power the electrolyzer to produce hydrogen which would be stored in tanks. When people need electricity, the stored hydrogen would put through a fuel cell.”
3. Solar panel roof that can be printed and painted: If solar power is easy to install as to paint your roof with sunlight resistant paint, it will lower the standard for the installation of solar power at home. This technology called silicon ink, and according to the U.S. National Renewable Energy Laboratory, solar cells showed 18% energy savings.
4. Large Panel Solar Film: SunFab ™ system uses silicon thin film technology to market the largest and most powerful panels in the world and combines inexpensive material.
5. Organic Solar Concentrators: Engineers at MIT have created a method to transform glass into a high-tech solar concentrator, using color glass to collect and emit light which is usually missing from the panel surface. This technology can create a building for use with glass window film to gather strength. Other companies, GreenSun, has developed a panel of light color where it catch the other parts of the spectrum of the sun, and does not require direct sunlight to work.
6. Space Based Solar: Japanese are developing a giant space station with solar power generators to transmit solar power to earth from 36.000 km above the earth within the next 30 years. The Japanese Government supports $ 21 billion project, which includes a space station solar power with solar panels cubical 4km, save electric energy of 1 gigawatt, enough for 300,000 homes in Tokyo.
7. Solar Roads: Solar Roadways concept, will make a way to use glass panels to collect and distribute solar energy to illuminate the light at night and hot in winter, with enough remaining energy to light homes and businesses. Discoverer, Scott Brusaw, estimating each mile of solar panels can be illuminated 500 houses, and is expected to make a panel for 12×12 need cost about $ 5,000.
8. SunCatcher: Stirling Energy System, contains a solar concentrator in the bowl structure supported by a convex mirror, can be used in Arizona soon. SunCatcher using glass system fitted with a parabolic bowl for concentrating solar power in high-efficiency Stirling engine, with each bowl produces 25.000 watts.
9. Solar Nanotechnology: Research workers at McMaster University in Ontario has developed a light-absorbing nanowires formed of excellent photovoltaic materials in thin but durable carbon-nanotube fabric. They also use small particles in a flexible polyster film where can lead to solar cells that are both flexible and cheaper than today’s solar cells.
10. Grid Ready for Solar: Andalay AC solar energy panels, made with Akeena Solar technology, integrate the racking, wiring and electrical grounding components to the panel. According to the company, this will against the damage, a lot of money in saving for 30 year lifetime. Andalay AC solar energy panels produce a safe AC power, and can be a safe installation process for users.

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Solar Cell

November 24, 2009 By: Admin Category: Solar Cells

What Does Solar Cell Mean?

You may have seen a calculator that has a solar cell? calculator that does not need batteries, and in some cases do not even have the off button. As long as you have enough light, so the calculator can be on at any time and forever. You may have seen larger solar panels, such as in housing or traffic lights, haven’t you? In this article I will review how solar cell work so it can deliver the energy and drive an electronic device.

Today the demand for electricity has become a major requirement in all corners. The presence of power plants sometimes do not solve the need for electricity especially in remote areas where the terrain is always an excuse. Here an alternative energy that can be easily found in nature and can be used as an alternative free energy replacing conventional electricity, because it can turn on household electronics such as televisions, radios and lights.

Solar cells made from pieces of a very small silicon coated with special chemicals to form the basis of solar cells. Solar cells generally have a minimum thickness of 0.3 mm is made from semiconductor materials incision with positive and negative poles. Each solar cell produces usually voltage 0.5 volts. Solar cells is an active element (semiconductor) that utilizes photovoltaic effect to transform solar energy into electrical energy.

Solar cells contain a connection (junction) between two thin layers made of semiconductor materials, each of which is known as a semiconductor type “P” (positive) and semiconductor type “N” (negative).

N-type semiconductor made of silicon crystals and there are also some other materials (typically phosphorus) within the limits that these materials can provide an excess of free electrons.

Electrons are sub atomic particles are negatively charged, so that the silicon alloy in this case known as N-type semiconductor (Negative). P-type semiconductor made of silicon crystal in which there is a small amount of other material (typically boron) which caused the shortage of material free electrons. Lack or loss of electrons is called a hole. Because there is no or lack of electrons electrically negative charged then the silicon alloys in this case as a semiconductor type-P (Positive).

Composition of a solar cell, the same as a diode, consisting of two layers, called PN junction. PN junction obtained by staining a pure semiconductor silicon (valence 4) with the impurity valence 3 on the left side, and one on the right impurity stained with valence 5.

The effect of the electric field in a PV cell

Operation of a PV cell

Basic structure of a generic silicon PV cell

Thus formed on the left side that is not pure silicon again and called P type silicon, while the right side is called silicon type N. In the pure silicon there are two kinds of electrical charge carriers are balanced. Positive electric charge carriers called holes, while the negative are called electrons. After a desecration process, in the P type silicon formed holes (positive charge carriers) in a very large number compared with the electron. Therefore, in the P type silicon holes are majority charge carriers, while the electrons are minority carriers. Conversely, in the N type silicon is formed of electrons in a very large number so-called majority carriers, and holes called minority carriers.

In the silicon rod there was interaction between the P and the N. Therefore called the PN junction. When present, the P associated with the positive pole of a battery, while the negative polar associated with the N, then there is a relationship called “forward bias”.

Under forward bias, electrical currents arise in a series due to both types of charge carriers. So the electric current flowing in the PN junction is caused by the movement of electron and the movement of holes. An electric current is flowing in the direction of holes movement, but opposite direction with the movement of electrons. Just to further explain, electrons moving in the conductor material can lead to electrical energy. And electrical energy is called as an electric current that flows in the opposite direction to the movement of electrons.

But, if the P associated with negative pole of batteries and the N associated with positive pole, then now formed a relationship called “reverse bias”. In these circumstances, the hole (positive charge carriers) can be connected directly to the positive pole, while the electrons are also directly to the positive pole. So, clearly in the PN junction there is no movement of majority charge carriers either the holes or electrons. Meanwhile, the minority charge carriers (electrons) in the part P moves trying to reach the positive pole of the batteries. Similarly, the minority charge carriers (holes) in the N also moved to reach the negative pole. Therefore, in a state of reverse bias, in the PN junction there is also output current even in very small amounts (micro amperes). This current is often called the reverse saturation current or leakage current.

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Anything interesting in reverse bias. When the temperature of PN junction raised they will be able to enlarge leakage current. Means that if given the energy (heat), the minority charge carriers in the PN junction grows. Because the light is one form of energy, so if there is light that hit a PN junction may also produce enough energy to generate charge carriers. This symptoms are called photoconductive. Based on the photoconductive symptoms made of photodiode electronic components from PN junction.

In reverse bias, with increasing intensity of light that hit photodiode can increase the level of leakage current. Leakage currents can also be enlarged by increasing the battery voltage (reverse voltage), but the addition of leakage currents were not significant. When the batteries in the reverse bias circuit is removed and replaced with a load of resistance, the provision of light that can cause charge carriers both holes and electrons. If the illumination light is increased, current output was greater. Such symptoms are called photovoltaic. Light can provide enough energy to enlarge the number of holes in the P and the number of electrons on the N. Based on the symptoms of this photovoltaic electronic components can be created photovoltaic cell. Because usually the sun as a source of light, the photovoltaic cell is also called the solar cell (solar cells) or a solar energy converter.
So the solar cell is essentially a large photo diode and designed by referring to the photovoltaic symptoms so that could produce the greatest possible power. P type silicon is the very thin surface layer so that light can penetrate directly reach the junction. Part P is given ring-shaped nickel layer, as a positive output terminal. Under the P is the N type that is coated with nickel as well as the negative output terminal.

To obtain a large enough power required much of solar cells. Usually, solar cells arranged form the shape of the panel, and is called the photovoltaic panels (PV). PV as a source of electric power was first used in satellites. Then PV as an energy source for cars, so there are solar electric car. Now, in foreign countries, PV has started to be used as a roof or wall of the house. Sanyo has made even a semi-transparent PV that can be used as a substitute for glass.

After getting the output of the solar cell is a direct electrical current can be used to load utilized. But also the electric current can be used as a charge stored by the battery to be used when needed, especially at night because there was no sun.

If the solar cell is used for storage into the battery, then the resulting voltage magnitude must be above the battery specification. For example the battery used is 12 volts, the voltage produced by solar cell must be above 12 volts in order to perform charging.

We recommend that before carrying out the charging battery should be empty because the incoming flow will be filled with the maximum. The unit capacity of a battery is the Ampere-hour (Ah) and these characteristics are usually found on the label of a battery. For example a battery with 10 Ah capacity will fill up for 10 hours with the solar cell output currents of 1 Ampere.

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Silicon Solar

July 18, 2009 By: Admin Category: Solar Accessories

Comparison between the Amorphous and Crystalline Silicon Solar Panels

Solar panels are generally made from crystalline or amorphous silicon. Amorphous means that the solar cells does not have a crystal structure. When you see a lot of solar panels, you will notice a mosaic pattern. This mosaic is different silicon crystals that grow together in different orientations.

Amorphous type silicon solar panel do not have a crystal structure. Amorphous silicon is as a glass or obsidian. The silicon atoms are all frozen together in a random way. However, in crystalline type silicon solar panels, the silicon forms a lattice or regular repeating crystal structure.

Excess crystalline type solar cells is that they are generally more efficient. However, the crystals need time to grow and therefore more expensive to produce.

Amorphous silicon panels cheaper to produce, because no crystal structure that needs time to form. However, the amorphous solar panel is less efficient.

Some solar panel manufacturers such as Sanyo has been producing solar panels that use a combination of amorphous and crystalline silicon for maximum effect. High efficiency crystalline silicon can be used to capture most of the energy, but the various layers of amorphous silicon is added to capture what is left.

So, what amorphous construction silicon panels? They are solar panels made from a non-crystalline variety of silicon.

Note: When purchasing crystalline or amorphous silicon panel it is important to consider the cost with efficiency. A crystalline silicon panel may be very efficient, but cost can be overcome benefits. Amorphous panel less efficient, but they are also cheaper. So, there is always a balance between costs and benefits.

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Solar How

July 03, 2009 By: Admin Category: Solar Power

How Solar Power Plant Installation

Solar Power Plant is a system of clean energy and produce electricity from sunlight. Also support the issue of global warming. Because energy is widely used by State Electricity Enterprise is the energy that can not be renewable (fossil) fuel such as kerosene, gas, coal, etc. Whereas current cost of fuel has begun to become dearer. If using the sun is free energy available abundant.

Installation and Operation is very easy, enduring long and a very inexpensive investment option to be public at this time. Can be used to meet electricity needs anywhere, especially in rural areas or areas that do not (not yet) reached by State Electricity Enterprise network.

Various Benefits of Using Solar Power Plant:

• Source of energy that never runs out and is very environmentally friendly
• Can be used anywhere, especially areas that have not yet reached by State Electricity Enterprise network
• No need to pay State Electricity Enterprise
• Without fuel and pollution-free
• Not require special treatment
• Free from all treatment
• Can be used to light a variety of electrical equipment, especially for lighting the lamp, radio, cassette, TV
• Can be used for emergency lighting when electricity of State Electricity Enterprise, have extinction (power off)
• And so on

Principles of Sun Power Plant

In the daylight the solar panel receives light (rays) of the sun and then converted into electricity through the Photovoltaic. Electricity generated by solar panels can be directly channeled to burden or stored in Electric Box System (EBS), before use to load, light, radio, TV etc.

At the night, where the solar panel does not generate electricity. Electricity that has been collected (stored) in a Electric Box System (EBS) will be used. To turn on electrical equipment, especially the lighting, etc.

Components of Solar Power Plant

1. Solar Panel:
Change the sunlight into electricity. Modular form of the solar panel provides the ease of the electricity needs for various scale of the needs.

2. Electric Box System (EBS):

• Set of traffic from the solar panel to the load
• Saving electric current generated by the solar panel before used to drive the load. Burden can be a lamp, electronic device and other equipment that requires electricity
• Very flexible in placement, you can take shift about.

The Design of Solar Power  Plant – The Practical and Flexible

With a flexible design that can be possible to increase the capacity of electricity with solar panels only add (maximum 2 solar panel) for each package.

Installation HOW VERY EASY

1. Place solar panel outside the house (roof, roof tile, or make your own tower, etc.) directly to the sunlight adjust with the situation / place / situation you secure place
2. Pull cable from solar panel, and enter plug to EBS IN DC (There are DC IN and DC OUT) Plus ON-OFF if you use (do not forget to note the ON-OFF key If you use ON if not used right OFF). For a cable if less in length you can add/connect your own. Set EBS & cable installation neat and safely out of reach of children etc.
3. If solar panel at work, on the EBS have red indicator lights, when charging energy from the panel to EBS will be full, red indicator light will turn on flicker, if it is full will be off. Green indicator lights mark the flow you are working.
4. In the EBS (Electric Box System) have stop contact Out AC is useful to set the electronic equipment appropriate with watt and energy saved. You can also make your own plug combination for parallel needs. (Many stop contacts that have sold in the market with 2 holes, 4 holes, 6 holes, etc.) find the high quality.
5. Ready to use to set the lights, tv, radio, etc

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Solar Electric

May 22, 2009 By: Admin Category: Solar Electricity

The High Costs of Solar Electric Power

Executive Summary about Solar Electric by Klaus H Hemsath

Promotion of solar power generation is booming. Why are solar farms built when financial data clearly show that solar power is still the most expensive electricity generation technology available?

Solar power plant developers and marketers obviously know that they need to lower costs. Cost reduction is, however, expensive and takes time. There are two major technologies for solar energy conversion. Electricity production with steam is a very mature technology. The other technology is the direct, photovoltaic conversion of sunlight into electricity. This technology will most likely become the dominant solar electric power generating technology – eventually. The concentrated sunshine creates very high surface temperatures on the solar panel. To save solar panel area and make the solar panel price competitive, one must cool the surface of the solar panel very efficiently to prevent it from melting and destruction.

Present production costs for generating electricity with solar panels are hovering around $0.50 per kWh. Right now, solar power does not yet make economical sense.

None of the available technologies using renewable energy can compete with the cost of electricity generation from coal.

The technologies for generating electricity with solar power, wind power, marine power, and geothermal power are very well understood. At present, a respectable number of windmill farms and solar panel farms are being installed. Solar power does not make economical sense, yet. A random sampling of recent announcements of solar farm installations reveals that system installation costs are in the $3000 to $7500 per kW installed capacity. These plant costs loosely translate into a cost of producing electric power at $0.30 to $0.60 per kWh. This very unfavorably compares to the cost of electricity generation by any other technology.

As long as solar power constitutes only a very small fraction of overall electric power generation, the additional costs of storing intermittently produced electric power are not yet of concern. If the US is going to depend significantly on the intermittent production of electricity from solar power and wind power, it must begin to develop storage technologies for huge amounts of electric energy. Intermittent, renewable energies and electric energy storage are inseparable.

The Solar Electric Panel – An Inexpensive Way to Generate Electricity
Executive Summary about Solar Electric by Dan A Swanson

The solar electric panels, generally called solar photovoltaic panels, are made of a set of treated silicon cells arranged in a series array. They produce electricity on being exposed to the sunlight. A small solar electric panel will lessen the energy bills considerably, while a big solar panel will in fact budge the meter backwards. The contemporary solar electric panels are simple to install and are modular. The solar electric panels transform the sunlight to DC (direct current) electricity. Buy any of these solar electric panels according to your requirements.

Solar electric panels are the perfect answer to our increasing electricity bills and ever increasing reliance on depleting conventional energy resources. Make a one time investment in solar panels and generate free electricity for years to come. Solar electric panels are the need of the hour.

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