COST: The cost of harnessing solar energy is decreasing steadily, indicating that as technology advances, the costs of using solar energy and maintaining a solar power system will lower gradually. This makes solar energy much more attractive than burning fossil fuels because of its increasing cost.
CLEAN: Solar Energy is clean, renewable and reliable. Solar power does not emit any harmful toxins or pollutants, making it very environmentally friendly.
CONVENIENT: Solar power is convenient to obtain, no excavation or pumping is required to access the energy source, as in fossil fuels. Since sunlight is readily available every day at least to some degree, it is easy to make use of its energy.
DURABLE: The reliability factor is important for any power source. Solar power systems can be expected to last a long time. They are tough-wearing and sturdy. With a proper system, solar energy can keep a house off the utility power grid completely with a consistent power supply.
SAFE: A solar power system is neither too dangerous nor too complicated for most people to run. It requires no supervision from the government or any other agency because it poses no risks.
- THE POWER CHASERS!
the sun left its mark!
Monday, June 9, 2008
SOLAR ENERGY TRAPPING DEVICES! Now that we already know how useful solar energy can be, let's find out how it can be trapped!
1. SOLAR PONDS A solar pond is simply a pool of water which collects and stores solar energy. It contains layers of salt solutions with increasing concentration (and therefore density) to a certain depth, below which the solution has a uniform high salt concentration.
With this structure, solar ponds can collect energy in a large scale, having integral heat storage capable of supplying thermal energy. Solar ponds are suitable energy-trapping sources, especially in the developing countries as it can be constructed anywhere. Below is the image of a huge solar pond:
2. Solar Panels
A solar panel is a device that collects and converts solar energy into electricity or heat. Solar photovoltaic panels can be made so that the sun's energy excites the atoms in a silicon layer between two protector panels. Electrons from these excited atoms form an electric current, which can be used by external devices.
3. Solar Cells
A solar cell or photovoltaic cell is a device that converts solar energy into electricity by the photovoltaic effect. Individual cells are used for powering small devices such as electronic calculators.
-Emily.
the sun left its mark!
Sunday, June 1, 2008
Principles Behind Solar Cookers
This is a continuation to the previous post about solar cookers. Here, we will be sharing some fo the principles behind solar cookers:
Most solar cookers work on basic principles: sunlight is converted to heat energy that is retained for cooking.
Fuel: Sunlight
Sunlight is the "fuel." A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Solar cookers don't work at night or on cloudy days.
Convert sunlight to heat energy
Dark surfaces get very hot in sunlight, whereas light surfaces don't. Food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture.
Retain heat
A transparent heat trap around the dark pot lets in sunlight, but keeps in the heat. This is a clear, heat-resistant plastic bag or large inverted glass bowl (in panel cookers) or an insulated box with a glass or plastic window (in box cookers). Curved concentrator cookers typically don't require a heat trap.
Capture extra sunlight
One or more shiny surfaces reflect extra sunlight onto the pot, increasing its heat potential.
In our daily life, cookers are nealrly indispensable and very common to all of us. The evolution of cookers also has many changes from the most primary to the most modern and convenient ones. However, types of cookers like coal, oil or gas cookers have partly affected our environment with numerous toxic gas produced into the air. To solve this problem, they have invented electric cookers, but the limited and expensive source of electricity also becomes another problem for the scientists. Therefore, the appearrance of the solar cooker with the permanent resource and a great benefit for the environment has marked a new era of technology in household appliance.
HOW SOLAR COOKERS WORK
Types
Heat-trap boxes, curved concentrators (parabolics) and panel cookers are the three most common types of solar cookers being used in numerous diverse kinds. Besides, several large-scale solar cooking systems have been developed to meet the needs of institutions worldwide.
1. Box cookers
Box cookers cook at moderate to high temperatures and often accommodate multiple pots. Worldwide, they are the most widespread. There are several hundred thousand in India alone.
2.Curved concentrator cookers
Curved concentrator cookers, or "parabolics," cook fast at high temperatures, but require frequent adjustment and supervision for safe operation. Several hundred thousand exist, mainly in China. They are especially useful for large-scale institutional cooking.
3.Panel cookers
Panel cookers incorporate elements of box and curved concentrator cookers. They are simple and relatively inexpensive to buy or produce. Solar Cookers International's "CooKit" is the most widely used combination cooker.
-Linh.
the sun left its mark!
Monday, May 12, 2008
SOLAR-POWERED ITEMS
1. Wii
2. Nintendo DS Lite
3. Watch
4. Copper Fountain
5. Pot
AND OF COURSE, THE USUAL STUFF YOU CAN FIND AT GIFT SHOPS, THEY'RE SOLAR-POWERED TOO!
LIKE...
AND...
see, solar-powered items are EVERYWHERE! just open your eyes a little wider, and i'm sure you'll find loads of them out there! (:
-Evelyn.
the sun left its mark!
Wednesday, April 30, 2008
Introduction
Environmental polution is always an intricate issue for the scientists all around the world. One of the main factors causing air polution is transportation including cars, motorbikes which produce tons of carbondioxide and other waste gases into the air. Although bicycles are obviously a better mean of transport for our environment, because of it's limitation in speed, people still prefer motorbikes and cars. However, now with the wonderful aid of solar energy, all has changed. Below is the project of a very creative guy who has made his own solar electrical bicycle by using solar battery.
Solar Electric Bicycle Project
This project was a way of using the ongoing power I am producing both from my 100w wind generator and 5w solar panel.
The basis of the project was a second hand Sinclair Zeta II bought on eBay for £21 ($40) - originally manufactured from 1997 - 2000
The Sinclair ZETA II consists of a rechargeable battery pack, which powers a lightweight motor unit over the front wheel. Touch a lever, and the unit pivots to bring a pulley-mounted belt into contact with the tyre. Press a switch, and the belt drives the wheel. This belt system is patented by Sir Clive Sinclair. When you no longer need power assistance, a flick of the handlebar switch takes the belt out of contact with the tyre.
Specifications
- Battery 12v 7Ah Yuasa sealed lead acid. - Motor 12v dc - 168 W max (thermal cut-out) - Charge time 14 hrs@ 500Ma - Max speed 11mph - Range Approx 5 miles on level road - no headwind.
Handlebar motor controls. 12v 7ah battery and fuse.
Zeta motor disconnected from tyre. Zeta motor engaged.
The addition of my 12v 500Ma (5w) solar panel with a 1 amp inline fuse connected was all that was needed to charge my bikes battery.
A silicone blocking diode connected to the positive terminal of the solar panel is necessary to stop reverse current from the battery.
If on a cloudy day I need more charging power I hook the battery to my 100w wind generators battery through a controller box to limit the current to 1.5 amps and that takes 4.5 hours to fully charge from flat. I check the voltage regularly with my digital multimeter, a charging regulator could be used if the bike is left for long periods of time in sunshine, they are available from maplin electronics price £9.99 code N82AU wiring example here
I use it daily to travel the 2 miles to work, however as expected the power from such a small motor is not great, best not to rely on the units power solely.
Best to consider it as pedal assistance, it really helps the old legs. I have read the zeta 3 (again no longer made) had a more powerful motor and quieter gear train.
No licence, tax or insurance needed (in the UK) + No fuel costs or parking fees or queuing in traffic!
This project cost me £30 ($50). I now have completely free powered transport - it can be done.
-Linh.
the sun left its mark!
Thursday, April 17, 2008
DISCUSSION ON ARTICLE Sun's Mysterious Waves Found; May Be Solar Wind Source
This article is indeed not easy to understand, especially when many scientific terms are used. Therefore, to understand this article better, let’s look into it and discuss.
· Main issues: This article is about the newest research of the scientists on the Powerful magnetic waves in the sun's atmosphere which was first predicted by and named after a Swedish physicist Hannes Alfvén. This research is aided by Hinode satellite.
· Definition of solar wind: Solar wind is a stream of charged particles flowing outward from the Sun with an average velocity of about 400 km/sec. It is a natural consequence of the Sun being so hot - the corona gas has too much energy to be gravitationally bound to the Sun.
· Significance of the article: - How is the research done? 1. Rapid-fire pictures of various solar structures are taken by the obiter’s instrument. 2. Hinode’s high-speed camera takes photographs of spicules every 5 secconds. 3. These pictures are then combined to a movie-like photo sequences to show how several solar structures interact with the long-suspected magnetic waves.
- “Breakneck” speed of charged particles through space? About two million miles (three million kilometres) per hour è from the sun they reach Earth's orbit within two days
- Benefit VS Danger: Solar wind is an endless clean energy VS it can carry "space weather" from solar flares or other disturbances on the sun's surface, causing auroras, disrupt satellites and radio communications, and even damage power grids è Understanding solar wind help scientists better predict the impacts of space weather
- Limitation: The new studies do not allow for the prediction of solar flares and other disruptive explosions from the sun.
-Althea.
the sun left its mark!
Monday, April 7, 2008
CARTOONS! :D
Below are just some cartoons which I've found on the Internet about solar energy, hope you like them! :D LAUGH, because hahaha laughter is the best medicine! :D (wait this is so corny ._. )
HAVE A HAPPY DAY! :D
-Emily.
the sun left its mark!
Sunday, March 23, 2008
ARTICLE 2
Sun's Mysterious Waves Found; May Be Solar Wind Source
Powerful magnetic waves in the sun's atmosphere may be the energy source that drives the solar wind, a suite of new studies from a Japanese-led mission reports. These so-called Alfvén waves were first predicted by Swedish physicist Hannes Alfvén, who won the 1970 Nobel Prize in Physics for his theory. (Read about the winners of this year's physics Nobel.)
The new studies of these waves were made possible by high-resolution instruments on the Hinode satellite, which was launched in September 2006. Hinode, which means "sunrise" in English, is a joint mission of the Japanese Aerospace Exploration Agency (JAXA), NASA, the Particle Physics and Astronomy Research Council (PPARC), and the European Space Agency (ESA).
The orbiter's instruments allowed researchers to take rapid-fire pictures of various solar structures. Certain images were then combined into movielike photo sequences that showed how several solar structures interact with the long-suspected magnetic waves.
"These observations are unprecedented," said Jonathan Cirtain, a solar astrophysicist at NASA's Marshall Space Flight Center in Huntsville, Alabama. "It's just like [the features] are waving at you."
Like Plucking Guitar Strings
The solar wind sweeps charged particles through space at speeds of about two million miles (three million kilometers) an hour—meaning that charged particles from the sun reach Earth's orbit within a couple of days.
"We live in the atmosphere of the sun," said Bart de Pontieu, a solar physicist at Lockheed Martin Corporation's Solar and Astrophysics Laboratory in Palo Alto, California. De Pontieu is lead author of another of the new Alfvén wave studies.
Normally the solar atmosphere is calm, but its wind can carry "space weather" from solar flares or other disturbances on the sun's surface.
These cause auroras, disrupt satellites and radio communications, and—in extreme cases—wreak havoc with power grids. Understanding solar wind could help scientists better predict the impacts of space weather—but the exact source of the winds has long been a mystery.
In 1947 the physicist Alfvén published a paper in the journal Nature proposing the existence of electromagnetic-hydromagnetic waves.
Since then the waves have been produced in the lab, but it was not until recently that researchers could detect the waves in the sun's corona. The new studies show that Alfvén waves occur when turbulence at or near the sun's surface causes magnetic field lines to produce wiggles that propagate outward.
"They're kind of like waves on a guitar string, in the sense that if you pluck a guitar string, the wave travels along [it]," de Pontieu said.
His team was able to spot the waves by looking at the motions of "spicules" in the chromospheres, a thin layer of the sun's atmosphere. Spicules are jets of hot gas that shoot outward from the sun's surface at speeds of 100,000 miles (160,000 kilometers) an hour, reaching heights of 5,000 miles (8,000 kilometers) in a matter of minutes.
Using Hinode's high-speed camera, the scientists were able to photograph spicules every five seconds. The jets are lined up along the sun's magnetic field lines, which stick out from the star's surface.
Alfvén waves make the spicules that form along the field lines seem to "dance," somewhat like a person wiggling a magnet in the middle of an array of iron filings.
X-Ray Jets
Similarly, the team led by NASA's Cirtain looked at the sun's x-ray emissions, particularly from high-energy jets near its magnetic poles.
These showed that Alfvén waves are created when tangled magnetic field lines "short circuit" and snap into new configurations. That causes the field lines to vibrate in response to the large quantities of energy being released.
Alfvén waves on the sun last for about ten minutes each, and Hinode's x-ray telescope allowed a new image to be taken every 30 seconds.
"We could directly observe the waves" moving in the images, Cirtain said.
Still another team, led by Takenori Okamoto of Japan's National Astronomical Observatory, was able to see similar effects in prominences, which are large plumes of gas rising hundreds of thousands of miles above the sun's surface.
Unlike spicules and x-ray jets, which lie near the surface, prominences extend into the sun's corona, where they can persist for many days. As the Alfvén waves rise above the sun's surface, they impart energy to gases in the sun's corona, propelling them outward.
"[Alfvén waves] are very good at propagating through the [sun's] atmosphere because they don't get damped easily," Lockheed Martin's de Pontieu said. "They carry a lot of energy." Not all of this energy reaches the corona, but mathematical simulations by de Pontieu's team indicate that enough does to accelerate the solar wind.
"There's kind of a wall between the chromosphere and the corona, and a lot of the waves get reflected," de Pontieu said. "But we've been able to show that enough get into the corona to provide the energy to drive the solar wind."
Solar Forecasting The new studies don't allow for prediction of solar flares and other disruptive explosions from the sun, the researchers caution.
"We're helping theorists develop better models of the formation of the solar wind," NASA's Cirtain said.
"The increased precision and accuracy of those models will allow solar weather forecasters to create a more accurate representation of the output of the sun on a day-to-day basis."
-Althea.
the sun left its mark!
Monday, March 17, 2008
THE SUN The Sun is indeed a priceless present of God from which humans have been endowed an endless source of power called “solar energy”. But, actually what have we known about Sun? Is it just a round cheese cake which rises in the East and disappear in the West every day, or are there also many other things about it that we haven’t known? In this journal today, I would like to post a short essay about the Sun and hope that it will provide you certain information about our Sun.
OUR SUN...!!!
1.Measurements Our Sun is a normal main-sequence star, one of more than 100 billion stars in our galaxy. The Sun is by far the largest object in the solar system with a huge diameter of 1,390,000 km and a great mass of 1.989 kg
Trying some simple calculation, you will see more clearly how big our Sun is. It is likely to take you nearly 100 years to walk restlessly around its perimeter, or luckily if you have a good car which provides you a speed of 60 km/h, your ten years will be burnt up by its heat as well (Wow...!)
As it is the closest star to Earth, the Sun is a very important source of heat which sustains life on Earth, and controls our climate and weather.
Conditions at the Sun's core (approximately the inner 25% of its radius) are extreme. The temperature is 15.6 million Kelvin and the pressure is 250 billion atmospheres. At the center of the core the Sun's density is more than 150 times that of water.
2.Composition The Sun is, at present, about 70% of hydrogen and 28% of helium by mass. Other elements are less than 2%. This elemental proportion changes slowly over time as the Sun converts hydrogen to helium in its core.
3.Huge amount of energy Nuclear fusion reactions taking place inside the Sun produces a great amount of output energy (about 3.98 megawatts. Each second about 700,000,000 tons of hydrogen are converted to about 695,000,000 tons of helium and 5,000,000 tons of energy in the form of gamma rays. That very huge amount of power travels outwards the sun and is continuously absorbed and re-emitted at lower and lower temperatures. After a long “journey” of from 146 to 152 million km, by the time it reaches the Earth’s surface, it is primarily visible light. For the last 20% of the way to the Earth, this energy is carried more by convection than by radiation.
4.Structure Photosphere:the surface of the Sun at a temperature of about 5800 K.
Sunspots: "cool" regions at only 3800 K (they look dark only by comparison with the surrounding regions), very large (50,000 km in diameter) and caused by complicated and not very well understood interactions with the Sun's magnetic field.
Chromospheres: a small region lying above the photosphere.
Corona:the highly rarefied region above the chromospheres at the temperatures of over 1,000,000 K. It extends millions of kilometers into space but is visible only during a total solar eclipse. The Sun's magnetic field is very strong (by terrestrial standards) and very complicated.
The Sun is about 4.5 billion years old. Since its birth it has used up about half of the hydrogen in its core, it will continue to radiate "peacefully" for another 5 billion years or so. But eventually it will run out of hydrogen fuel. It will then be forced into radical changes which will result in the total destruction of the Earth.
So, don’t ever repeat our ancestors’ mistakes in the past which may lead the seemingly “endless” energy of Sun to be “limited”. It must be always a remarkable issue when we are taking advantage of natural resources.
To end this essay today, I would like to show you a short funny video about the Sun and its important role in humans' life. Hope you enjoy it ^^
Box cookers cook at moderate to high temperatures and often accommodate multiple pots. Worldwide, they are the most widespread. There are several hundred thousand in India alone.
Handlebar motor controls. 12v 7ah battery and fuse.
