Solar Electricity Generation By Water
Posted on | June 8, 2011 | No Comments
Using solar cell arrays to produce electricity is a now-familiar application. Most applications that use PV (photovoltaic) modules are still small scale, except for certain experimental stations trying to generate power at the level of utility companies. Still, everything from lawn lights to full power supply systems for homes are available.
But there’s another way of generating electricity, one that’s actually been in use for some time: heating water.
Steam generation plants have been in use for decades. Usually, the water is heated by burning coal, oil or natural gas. The heated water is turned to steam, which drives a turbine. That circular motion can be used to generate electricity.
Michael Faraday, the great 19th century British scientist and inventor, discovered that if a coil of wire is turned near a magnet, electricity is produced. That effect is the basis for countless applications that use a generator to provide power. The same basic principle is at work in turbines, only in this case the turning is provided by steam power.
But the turbine doesn’t ‘care’ what heats the water that turns the blades that produce electricity. And using solar heated water is significantly less pollution producing than other methods, even taking the component manufacturing effects into account.
One such method is that used in ordinary solar water heating systems, which typically use collector panels atop a roof. The water is heated by the greenhouse effect and then passes down a series of channels and pipes into a storage tank.
But there’s a difficulty.
The total sunlight received in a given area at one time is fixed. It will vary depending on cloud cover, dust in the air and other factors. But it can’t be adjusted upwards, since we can’t control the sun’s output. However, by adjusting how that energy is used, we can control the amount of usable energy applied and how.
More efficient collector systems make that possible. One is the parabolic mirror method.
A mirror shaped roughly like a section of a sphere can focus the sun rays to approximately a point or line. Exactly how sharply focused and to what geometry is determined by the quality and shape of the mirror. A circular parabola, like a satellite dish, focuses to a point. A cylindrical parabola focuses to a line. That shape concentrates the energy received into a smaller area. That makes it possible to use the same energy to raise the water temperature much higher than by other methods.
By using parabolic troughs and other shapes, solar heating collectors can raise the water temperature to as much as 428F(220C). Water boils at 212F (100C). That extremely high temperature water creates steam under very high pressure in a contained vessel. The steam is then used to power a turbine to produce electricity.
Since the temperature and pressure are high, the conversion efficiency of the device is correspondingly high. That’s the result of a basic principle of the physics of heat. That makes it possible to create solar electricity generation devices that are as high as 40% efficient. PV (photovoltaic) panels range from roughly 10-15% efficiency.
Of course, such systems may not be for the average homeowner. Yet. But businesses are beginning to experiment with them as the cost of coal, oil and natural gas rises and the price of solar systems comes down. Some day it may well provide a significant percentage of the total energy needs of the average person, who could receive electricity from large solar turbine-based plants.
Using Solar Power to treat Water
Posted on | June 1, 2011 | No Comments
Using the energy from the sun to generate electricity gets a lot of press. But there are many other applications for solar power. One of the most important is for treating water.
Many countries around the world have impure water that causes diarrhea, typhus and other medical problems. The same is true of certain areas of the U.S. and other developed countries. Building small devices that can eliminate the problem is cost-effective using current technology. Individuals can even build their own.
Solar disinfection, or SODIS as it’s sometimes known, uses a very simple principle. It’s essentially the same as that used to pasteurize milk. Microorganisms that cause health problems can only function in liquids up to a certain temperature. Beyond that, even when they’re not killed, they are deactivated. Amoeba, bacteria and many other small disease-causing organisms can be rendered harmless by this method.
Implementing the method can be ultra simple. A gallon of water in a plastic jug can be treated in a few hours. Simply place the water in a clear, plastic bottle, preferably on a black background to ensure good absorption, and place it in the sun. On a sunny day the process may take less than three hours if the water is moderately clear to begin with. River water, obtained while hiking for example, can be treated this way.
PET plastic is preferable to PVC plastic for this application. PVC, polyvinyl chloride, type plastics have a slightly bluish cast. They block more UV, which is a more energetic form of light, and hence reduce the effectiveness of this method of water treatment.
There are other methods of solar-powered water treatment, too.
A solar water still can be bought or built for a few hundred dollars or less that will treat considerably more water than jugs. They’re usually made in the form of a rectangular container a few inches deep with a glass panel up the side and a siphon hose. The container is often covered with plastic. Glass blocks much of the UV.
As the sunlight heats the water, the moisture evaporates up and condenses on the relatively cooler glass above. The siphon hose draws off some of the water, which is not only freer of organisms, but contains fewer minerals and other compounds, such as chlorine.
The principle is basically the same as that used in desalination plants around the world.
Many locales have little drinkable water but large amounts of salt water readily available. Transforming the salt water into potable water employs the same evaporation technique, but generally on a much larger scale in desalination plants. Only a small amount of salt water can be consumed before it does damage to the kidneys. That’s one major reason that seawater has killed more than one sailor who found himself in the ocean trying to survive.
Solar radiation can kill pathogens in water and it can provide drinkable water in specialized applications. In short, solar power can generate clean water, just as it can generate pollution-free electricity.
Solar Panel Applications
Posted on | March 1, 2011 | No Comments
The image of a large, dark-blue panel atop a rooftop supplying solar-powered electricity is now familiar. Though relatively few homes have them, thousands of magazine stories have been written over the past 30 years accompanied by photos depicting them. Because of their relative rarity, such systems have become regarded as ‘the wave of the future’, with that future always just out of reach. The sticking points are always cost and efficiency.
But there are dozens of cost-effective solar-panel applications available today.
Lawn lights are a popular example. They come in the form of stakes about a foot long with lights mounted on the stake. On the top of the light are small solar panels. They don’t generate much power, but not much is needed for them to do the job. They can be quickly placed anywhere since they require no wires. They can last for years without any maintenance since they use no batteries and the bulbs are ultra-long lasting.
Calculators that are purely solar powered have been in use for decades now. But that same technology has recently been expanded to encompass laptops. Though they don’t currently generate enough power to run a standard hard drive or monitor, solar power has been combined with new inventions to make that unnecessary. They use something called organic cells.
A standard solar cell uses layered wafers of silicon doped with phosphorus. But other elements and more complex molecules are also subject to the photoelectric effect. Many organic molecules will shoot off electrons when struck with light. They’re not currently as efficient, but they make up for it by being flexible and super cheap. They can be incorporated into certain inexpensive plastic alloys.
That makes it possible to make an affordable keyboard or monitor that can be folded or rolled-up. With this technology, it’s possible to roll up a computer like a newspaper and tuck it in your pocket. Then, it’s unrolled when you want to use it and powered by the available light.
There are yet many more applications that can be powered by a solar system. One common use is electrical fencing. Whether you need to power a dog retainer system or a cattle barrier, low voltage systems are often used to keep animals in check. A small stun doesn’t harm, but it’s often enough to keep them from wandering outside the perimeter. Many can jump over standard fencing, but electrifying the system discourages the attempt.
Powered boats, like cars, have batteries that start the engine and power small electrical devices when the motor is off. Running lights, speedometer and more. But those batteries need to be recharged after use. In the usual case, the running motor recharges the battery, putting back the power needed to start it.
But, clearly, the fact that battery chargers exist means that method doesn’t always work. However, when you’re out on the water, and in many cases even when you’re near the shore, it’s difficult or impossible to use a standard charger. Electrical outlets aren’t universal in docks and nowhere on the water. A solar-powered charger can come in handy just when you need it most.
That same charger can recharge the battery in your RV just as easily. But beyond that emergency use, a solar-powered system can be useful for an RV in lots of ways.
Many times an RV is stationary, with its motor off. Some have generators to power the RV at those times. But generators are noisy and consume gasoline or diesel, producing foul smelling fumes. Not exactly what you want when you’re outdoors enjoying the fresh air. A solar power system can supply at least part of the energy needed. It can run a radio, power a DVD and/or TV, or a small refrigerator.
Electricity generation isn’t the only possible application either. Water heating is a popular home-oriented application for solar power.
Small parabolic dishes can be used to focus the sun’s energy into a small area. That energy is then transmitted to a water storage system. Not all such systems are solely for inside the house either. The hot water supplied can be used to bathe the dogs outside or provide an alternative to washing the car with cold water.
In fact, any kind of washing chore is usually easier with warm water and water from the hose gets cold quickly. A solar heating system can provide a reservoir of warm water to wash the exterior of the windows, supply a sink in the garage and other uses around the house and garage.
Solar systems today are more efficient and lower cost than ever. They provide freedom from dependence on the utility companies for all your electrical and hot water needs. That makes them a good deal.
What Is Solar Power?
Posted on | January 26, 2011 | No Comments
Human use of the sun’s energy may seem like a recent phenomenon. But, in fact, solar energy has been in use in various forms for thousands of years.
Apart from the obvious fact that the sun provides the energy for plants to grow that feed us, there are more technological uses that go back millennia.
The ancient Greeks knew how to harness steam power, some of it generated by solar radiation. Pre-industrial, they regarded the devices as amusing toys, primarily. But some applications were taken seriously. Archimedes designed and had built a large magnifying-type glass that was used to set enemy ships on fire. The Romans adopted some of this technology, as they did much of Greek science.
Thermometers, heat storage containers and many other devices were created over the centuries that relied on energy from the sun. Over time, those devices became more sophisticated and more diverse.
In 1839 another big leap occurred when Becquerel discovered the photovoltaic effect even though it would take another 100 years for devices based on it to become practical.
When sunlight hits certain materials, it causes the electrons in the atoms to get knocked loose from their associated atoms. Electrons moving within material constitute an electrical current. When that current is connected to a circuit, the power generated by the electrical flow can light bulbs, heat water or power a computer.
But electricity isn’t the only form of solar power.
In the 1920s some public heating systems used large storage tanks to trap solar energy. The heated water was then supplied to homes. Eventually, those systems couldn’t compete economically. Gradually, the cost of gas and electricity decreased to the point that it was below those systems’ operating costs.
Those systems fell into disuse and were eventually forgotten. But the technology existed as a mainstream method, not a crank alternative. It worked and was, for the time, a cost-effective solution.
Now there are hundreds of viable applications of solar power, which in one way or another convert sunlight received at the surface to power devices, heat water and supply other energy needs.
Satellites have used solar panels and associated technology to supply needed power. The systems are expensive, but compared to the total they’re a very small fraction of the cost. Closer to home, the same kind of technology powers phones or lights along some highways.
And it isn’t just esoteric applications that benefit from solar power either.
Solar heating systems are employed in thousands of homes. Though solar powered electrical systems are less common than utility power, they are in wide use in rural areas where people want or need to supplement their supply. Many cabins in the Pacific Northwest are too far from the utility company lines to get electricity that way.
Not all devices or systems are hugely expensive, either. Low-cost solar powered lawn lights are dotting many homes today. Calculators powered by tiny solar panels are so cheap they’re often given away as promotional items by advertisers.
Solar power can’t yet compete with large scale electricity generation by big utility companies. But costs are coming down and the applications are growing. It’s had a long past, but the future of solar power looks bright.
Rent Your Solar Electricity
Posted on | November 22, 2010 | No Comments
One of the hurdles any homeowner considering solar generated power has always faced is the high upfront cost. Powering the average home using the sun’s energy requires fairly large solar panels. Most panel systems cover most of the south facing roof of the house. But the cost of the panels alone can easily be around $10,000-$16,000. Add batteries, installation and related costs and you are looking at an initial investment of anywhere from $32,000 to about $50,000.
Many find the cost worth it in order to be independent of the local utility company. In rural areas, power outages are common. Wind storms knock trees onto the lines. Transformer blow outs are common. Many components of such systems are decades old and there’s too little income or other incentives for the power company to upgrade. Having an ‘off-grid’ system provides at minimum a backup during times when the power is out.
Given that the pay back on home solar panel systems can be 20 years or more, some may still see the initial cost as too high. They feel compelled to endure the occasional blackout.
But upfront purchase of the total system isn’t the only option today. There are various loan, lease, rebate or grant systems that can offset part or all of the cost.
Federal tax rebates or outright payments help somewhat. Special legislation in most states allows utility companies to enter arrangements that can reduce the cost of solar power. Some contracts and systems allow for purchasing back any excess solar power. If your system generates more than your home needs, the difference goes into the utility grid. You receive a rebate on your bill.
Many companies will subsidize part of the cost by offering a discount for homeowners who install a solar power system. Not many companies will pay you to purchase less of their product or service. But the crazy quilt of regulations in electricity generation gives the utility company a financial incentive to do just that.
There are a few companies just now starting up that promise to lease equipment. That opens the option of lowering the major share of the upfront cost of solar systems. Just as when leasing a car, the total cost over time may be slightly higher. But lowering the initial investment from $50,000 to $1,000 puts a solar power system within reach of many more people.
Most people today own their home for less than seven years. That’s one of the major reasons mortgage companies can offer the flexible rates and terms that have become common in the past 15 years. That fact affects the feasibility of installing a solar system as well.
Most people who only expect to own their home for, say, five years are going to be reluctant to sink $50,000 more into it. Installing a solar system raises the value of a home, certainly. But it rarely raises it enough to get a new buyer to cover the total cost. But leasing means the equipment can be returned after a set period of time. That opens up new options.
With changes in technology and financial arrangements, solar power systems are becoming more attractive. Investigating all the options may well put one within reach for you.
DIY Solar Hot Water
Posted on | February 9, 2010 | No Comments
You need to hot water in your home and the boilers that produce the hot water need a lot of electricity/gas/oil that all seem to be increasing in price on a monthly basis. So I am sure you agree that it makes sense to build yourself a home made solar hot water system that will helo reduce the power consumption and in turn your monthly utility bill.
Did you know that a solar water heater installed at home will save your electricity bills by Upto 33% and the installation of the system is very simple? You can easily get the parts and make the solar heater in your home backyard for less than $100.
Let us read further and come across some information that will really assist us in building our own solar hot water system and how this benefits the overall environment and the global warming.
The latest guide Diyhotwater.com has been released that will help you achieve the goal mentioned above. The sun rays emitted from the sun produces a vast amount of energy into the atmosphere. This energy is utilized as power that gives a positive impact on the environmental and will save you hundreds of dollars on your power bill.
The advantage of these DIY plans is that they can be downloaded from their site online and one can start the project in just a few minutes. Solar heaters have been giving productive results in hot and cold climates. The heaters keep the water warm and this eliminates the use of electrical applicances.You will notice the savings from the very first month of the installation of the heaters at your home.
The design and construction of a solar water heater is very simple and only needs few days to complete it. Most of the materials are readily available at any hardware store and you can complete the entire unit for less than $100. This is a one time investment but has long term gains.
The DIY Project has proven technology that covers all the topics in detail. A beginner can easily understand the instructions given in the guide for installing a solar hot water system. This is only the foundation. One can later find lot of other utilities of the solar power that can be used to generate power to other appliances. Solar power has been used for cooking purposes, for running a laptop or used for charging the mobile phones.
So, why not start with a solar heater and start reading the DIY Guide that will surely gave some dollars in your pocket.
Solar Technology and Cost
Posted on | November 25, 2009 | No Comments
Solar power technology has been around in some form or another for thousands of years. Even many modern solar device designs are now decades old. Yet, they have not fulfilled the promise that many hoped. Why? Two reasons: efficiency and cost.
Of the approximately 1,000 watts per square meter of sunlight power falling on the surface of the Earth (at the equator), only a small portion can get converted into usable electricity. Part of that loss is because of internal losses. Of the photons that hit a solar panel, only some will knock loose an electron. Of those, only some will travel down the module and into the device before being recaptured.
The latter effect is an issue called carrier lifetime. The longer the electrons wander around loose, the more likely they are to flow out of the module and down wires to an outlet. Most modules can only achieve in the neighborhood of about 10-15% efficiency. But several companies have raised the efficiency of their devices to as high as 20% by extending that carrier lifetime.
By contrast, solar thermal devices use sunlight-heated salt water panels to generate steam that can be turned into electricity. The efficiency is often as high as 30%. But not only are such devices expenses, they are high risk. The high temperature and pressure of the water can do considerable damage if it escapes.
Apart from efficiency considerations, costs remain relatively high.
Most types of solar panel remain fairly expensive. A 30-watt module costs in the neighborhood of $250, while a 195-watt panel will run almost $1000. In order to install a solar panel power system for a modest home will require panels costing somewhere around $10,000-$16,000. Add batteries and other components and the cost is anywhere from double that to triple or more.
Fortunately, as oil and natural gas prices continue to rise, manufacturers have responded. As the market matures for solar technology, research dollars have been spent to come up with new ways of increasing efficiency and lowering costs. Even with the relatively high price of large application panels, the cost is still much lower than it used to be, accounting for inflation.
The cost of PV (photovoltaic) cells has been falling by about 15% per year for the past 10 years. Given that they can easily last 20 years, they can pay back the initial investment, while providing clean power.
And improvements continue. A major European chip maker, ST Microelectronics, now has prototype solar cells that are expected to be considerably cheaper than today’s panels.
Organic compound solar panels are making their way into certain applications like computer keyboards and monitors. Those flexible plastics allow a computer to be folded up or rolled like a magazine. While still expensive, the costs are coming down as the technology matures. A French-Italian company expects to produce an organic cell soon that it estimates will produce electricity at around 20 cents per watt, compared with about $4-$8 per watt for ordinary solar power.
Water heating by solar power has costs that vary, too.
In the 1920s some municipalities used large storage tanks to solar heat and store hot water that was then supplied to homes. As the price of electricity and oil came down, which were used to heat water, they were no longer cost-effective.
But as things progress, those old ideas are becoming new again. Such methods may well soon be competitive again, if current research bears fruit. With the price of oil and electricity from gas and coal-fired plants continuing on the trend of the past 10 years, it would only take a small improvement for new applications to be economic.
Solar Water Heating!
Posted on | November 17, 2009 | No Comments
When most people think of solar power they imagine large, dark blue panels supplying electricity to a home or business. And that’s certainly one very popular application. But there are other ways to harness the energy of the sun. Solar heating is one, and its roots actually go much further back than the use of photovoltaic arrays.
Using directed sunlight to warm water goes back thousands of years. Crude mirrors and lenses were used by the ancient Greeks to warm water. In the 1920s some municipalities had functional solar systems that heated water supplied to homes.
Today, those applications have taken on the shine of high technology.
One common form is the use of collector panels, often mounted on a rooftop. Unlike photovoltaic modules, these arrays don’t use layered silicon wafers to generate electricity. Instead, they are more like large, thin, double-paned windows that contain water often mixed with types of salt. The sunlight heats the water by means of the greenhouse effect and the water moves through a series of channels, tubes and pipes into the home or business.
The greenhouse effect, as most people know by now from discussions of global warming, occurs when light enters a transparent medium, but not all the energy is allowed to escape out again. It happens to a high degree with glass because the material allows certain wavelengths of the light spectrum, such as infrared, to enter more efficiently than it lets the energy back out again. So, there’s a net gain in energy on the inside.
Heated water has direct uses, obviously. Whether it’s showering, washing dishes or other purposes, nothing more has to be done to the water other than simply make it available. That’s typically done by storing the heated water in essentially the same way as with ordinary water heaters.
In the ordinary hot water system the water heater storage unit also heats the water. With a solar-powered water heating system there’s no need to, since the water that enters the tank is usually between 95F-150F (35C-66C). The storage tank acts like a big thermos bottle. It’s double-lined and/or made of well-insulated material so the heat doesn’t dissipate much out the walls of the tank.
The temperature range of such systems is fully adequate for bathing, cleaning clothes and other ordinary applications. The only difficulties are ensuring enough sunlight to generate enough heat, and minimal loss of heat through the panels and pipes.
Costs can run to $50,000 or more, though. And local climate conditions may limit the usefulness of the system. But given the local cost of electricity or gas, a home or business solar water heating system may well pay for itself over 10 years. Or you could have a look at building your own solar water heater, you can have a look here.
Tags: diy solar water heating > solar heating > solar water heating
An Interesting DIY Solar Panel Video
Posted on | November 16, 2009 | No Comments
If you want to learn more about DIY Solar Panels I would highly recommend you check out GreenDIYEnergy.com
Enjoy and Thanks
Gavin
How Solar Power Works
Posted on | October 14, 2009 | No Comments
Solar power, particularly when it’s used to provide home electricity needs, may seem like a relatively recent invention. And it’s true that large, cost-effective panels that form the core of most systems have only been in use for about that past 30 years. But the underlying method they employ goes back to 1839, when it was discovered by Becquerel. He found that shining sunlight on an electrolytic cell would produce a current.
Other scientists built on that work. In fact, while Albert Einstein is most well known for the Theory of Relativity, he received his 1921 Nobel Prize for something quite different. According to the Nobel organization it was ‘for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect’. His paper on the subject was written in 1905.
The photoelectric effect is essentially similar to what solar power enthusiasts and workers know as the photovoltaic effect, the principle Becquerel first found. When light, in this case from the sun, strikes certain materials it knocks loose electrons from their associated atoms. Those moving electrons create a current that can flow through the material to provide electrical power.
Those materials today are typically some type of doped silicon. ‘Doping’ is another way of saying that other elements are deliberately introduced. In other applications, those impurities would be undesirable. In solar power, they’re essential. Pure silicon has its uses, but it’s not a good conductor of electricity. Adding phosphorus in just the right way, for example, turns them into semiconductors.
Certain specialized applications use gallium-arsenide or other materials, instead of silicon. But because of their relative rarity the cost is much higher. Silicon is a major component of ordinary sand and hence plentiful.
The silicon-phosphorus compound is arranged in layers, then connected to a grid to enhance the flow of electricity. It reduces the resistance losses. Then terminals are installed to allow for the electricity to flow into the home electrical system. The whole assembly is covered with glass to protect it and forms what’s known as a PV (photovoltaic) cell. Those cells are then arrayed into a module. Modules can then be connected together into a complete system.
Those modules comes in various sizes that determine how much electricity they generate. All other things being equal, the larger the area, the more power they can produce. Naturally, the larger panels tend to cost more.
Though the solar energy reaching the surface (at the equator) is about 1,000 watts per square meter, not all of it is usable energy. A square meter is a square whose sides are a little larger than three feet – it’s about 10.7 square feet. Apart from losses due to latitude, atmosphere, dust and other natural factors, the modules themselves only convert with about 10-15% efficiency.
The growth of solar power as a practical energy production method depends heavily on increasing that efficiency and lowering the costs of production. To a degree, that efficiency is bound by certain difficult-to-get-around physical constraints, so most of the research efforts involve attempts to lower the manufacturing costs.
When or if that happens, solar power applications may well become even more commonplace in homes and businesses than they are today.