From the monthly archives:

December 2008

Basic Principles of Solar Energy


How Solar Energy is Created

Solar energy consists of the light and heat emitted by the sun, in the form of electromagnetic radiation.

With today’s technology, we are able to capture this radiation and turn it into usable forms of solar energy – such as heating or electricity.

Although one could go into technical dissertations on the subject of electromagnetic radiation, how it is converted into solar energy, and the exact qualities of its electromagnetic rays, this is not something the average person needs or wants to know.

But in order to benefit the most from the use of solar power, there are a few facts you should know. Knowing these facts can assist you to make a sound decisions, when looking at the use of solar power as a clean energy source for your home, RV, or whatever the case may be.

Available Solar Resource

The technical feasibility and economical viability of using solar energy depends on the amount of available sunlight (solar radiation) in the area where you intend to place solar heaters or solar panels.

This is sometimes referred to as the available solar resource.

Every part of Earth is provided with sunlight during at least one part of the year. (I say “part of the year” as the north and south polar caps are each in total darkness for a few months of the year.) The amount of sunlight available is one factor to take into account when considering using solar energy.

There are, however, a few other factors which need to be looked at when determining the viability of solar energy in any given location. These are as follows:

* Geographic location

* Time of day

* Season

* Local landscape

* Local weather

Because the Earth is round, the sun hits its surface at different angles, at different locations on the globe. This ranges from 0º (just above the horizon – a good example of this is the north pole during the winter) to 90º (directly overhead, at and near the equator).

When the sun’s rays are vertical (directly overhead), the Earth’s surface gets a maximum of solar energy. The more slanted the sun’s rays are, the longer they have to travel through Earth’s atmosphere before reaching the surface (becoming more scattered and diffuse as they go along).

The more scattered and diffuse the sun rays are, the less concentrated the solar energy is. Because of the fact that the Earth is round, the polar regions never get direct sunlight, and, during their respective winter months, they receive no sun at all.

The Earth travels around the sun, in an elliptical orbit. Because of its elliptical path, the northern hemisphere of the Earth is closer to the sun during one half of the year, and the southern hemisphere is closer during the other half of the year.

When one part of the Earth is closer to the sun, it receives more concentrated solar energy. This is the time of year that is referred to as “summer.”

But regardless of summer or winter, the 23.5º tilt of the Earth’s axis plays a larger role in determining the amount of sunlight striking Earth at a particular location. The tilting of the earth results in longer days in the northern hemisphere during one half the year, and longer days in the southern hemisphere during the other half of the year.

Areas such as the United States and Europe receive more solar energy between May and September – not only because days are longer, but also because the sun is almost directly overhead during this season. The sun’s rays are far more slanted during the shorter days of the winter months. Cities such as Denver, Colorado, receive nearly three times more solar energy in June than they do in December.

Diffuse and Direct Sunlight

As sunlight passes through Earth’s atmosphere, some of it is absorbed, scattered, and reflected.

The following is a general list of materials that cause the sunlight to be diffused:

* Air Molecules

* Water vapor

* Clouds

* Dust

* Pollutants

Sunlight affected in this way is referred to as diffuse solar radiation or diffuse sunlight.

Sunlight that reaches the Earth’s surface without being diffused is called direct beam solar radiation or direct sunlight.

The sum total of all diffuse and direct solar radiation in a given location is called global solar radiation. It is the total amount of sunlight hitting the Earth at any specific spot, both direct and diffuse combined.

Pollution and other atmospheric conditions (such as weather patterns) can reduce direct sunlight by 10% on clear dry days. They can reduce direct beam radiation by 100% on thick, cloudy days.

Note that the absence of direct sunlight does not imply total darkness, as some diffuse light will still get through.

Measuring Sunlight and Solar Energy

Scientists measure the amount of sunlight available in specific locations during the different times of year.

They are then able to estimate the amount of sunlight which falls on similar regions at the same latitude with similar climates and conditions.

Measurements of solar energy are normally expressed as “total radiation on a horizontal surface”, or as “total amount of radiation on a surface tracking the sun”.

In this last case, the assumption is that one is using a solar panel that automatically tracks the sun.

In other words, the solar panel would be mounted on a tracking device so that the panel would remain at right angles to the sun throughout the day.

This system is primarily used for industrial setups, when it is used at all.

Solar Energy Measurements

Radiation data (the amount of solar energy available at a given location) for solar electric (photovoltaic) systems is often represented as kilowatt-hours per square meter (kWh/m2). Direct estimates of solar energy may be expressed as watts per square meter (W/m2).

Radiation data for solar water heating and space heating systems is usually represented in British thermal units per square foot (Btu/ft2).

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Anna supports of clean living and the use of renewable energy in order to combat pollution and Global Warming, as well as the humanitarian and economic consequences of dependency on fossil fuels.

Visit Anna’s blogs, Solar Power and Alternative Energy, to find more information on solar power and alternative energy.

You can also find a wide variety of solar power equipment, solar battery chargers, portable solar power, solar water heating, solar powered weather stations, solar fountains, solar lights, home solar panels, and more, at her Solar Power Store.

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How Solar Energy Works – A Brief Overview to Understand


Do you know how solar energy works actually? Some people don’t care too much on how solar energy works and it may happen on you too. Though, it will be very valuable to know how solar energy works for human being.

Solar power is most likely the most viable and cleanest form of renewable energy. The advantages of solar energy beats any other form of energy that depletes the natural resources of our planet and pollutes the environment. People of early civilizations have used this eternal source of natural power. They were familiar with how solar energy works at that time.

As the concern about the future of more conventional power sources grows, scientists are once again switching to solar power for running profitable and household activities. A better understanding of how the solar energy works is being combined with technological innovations in order to arrive at an affordable way of using energy from the sun for supporting life on earth.

Passive and Active Use of Solar Energy

The classic example of human understanding of how solar energy works can be seen in particularly designed buildings that face south (facing north in case of locations in the southern hemisphere). This allows maximum solar light and the associated heat to enter the building while minimizing the same in summer.

This kind of expertise in architecture has come to be known as passive solar design for buildings. A more active use of solar energy is made by creating particular kinds of material-called solar heat collectors-for gathering and holding solar energy. To get solar radiation, these collectors are located in the open place, mostly on the building’s roof.

Solar Heating Systems

Specifically designed lenses and mirrors are used for concentrating sunrays on a particular point or object so as to heat it up. Concentrated solar rays can generate a temperature as high as 3000 Celsius. Examples of such relatively simple heating systems include parabolic dishes parabolic troughs and central receivers. From a commercial point of view, parabolic troughs have so far been most victorious, especially in the American state of California.

Solar Electricity

Technology of photo electricity is the result of modern understanding of how solar energy works. The example of it is the electricity which is produced by sunlight. In 1839, a French scientist Edmund Becquerel reported the first observation of electric current produced in a substance by incident sunlight. Later, in the 1950s, Scientists at the Bell Laboratories invented Photovoltaic cells.

These cells were made of silicon and could change a small part of solar radiation directly into electrical energy when sunlight falls on their surface. These PV cells have been enhanced both in terms of affordability and efficiency commercial over the periods.

Generally, commercial and scientific projects usually use PV technology. Nevertheless, PV technology is lately used for using solar energy at homes. Since the understanding of how solar energy works increase in the world, new means of utilizing solar energy is needed for supporting life of human being on earth.

Does that answer your question? For further explanation about how solar energy works, you can find the complete guide here!

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What's A Solar Chimney?


A new solar energy technology solution has been put to the test, and has been given the go-ahead for production in Australia.

This new solar power station is based on solar tower technology designed in Germany. The most fantastic thing about this new technology is the simplicity of its design, and its ingenious use of basic principles of physics to create energy.

So what is this new solar energy plant?

This new solar tower, also referred to as a “solar chimney,” uses solar power to turn wind turbines.

Solar energy to turn wind turbines?

How does this work?

Well, the simplest way to describe it is to compare it to a huge greenhouse with a large chimney.

As we all know, hot air rises.

The greenhouse within the solar chimney system captures the heat of the sun. The heated air in the greenhouse is then allowed to escape through a huge chimney.

Before the air escapes through the chimney, it is forced to pass through wind turbines, which are in turn used to generate electricity. You can see a diagram of it here.

The beauty of this technology is that it uses centuries-old tried-and-true principles of updraft. This is the same principles used for chimneys in open fire places. When you light a fire in your fireplace, your house doesn’t fill up with smoke. This is because of the suction which is created by the hot air rising up through the chimney. This pulls the smoke up through the chimney as well.

But in the case of the solar tower, we are not using a fire to create hot air. We are simply allowing the sun to do its thing: heat stuff up. In this case, the sun heats the air up, and the air rises through the solar chimney as a result.

Australia is the first country to build this type solar energy power plant for commercial use.

The central tower will be over 3000 feet high and 400 feet in diameter.

It will use 750,000 cubic yards of concrete.

The solar energy collector (greenhouse) will contain thirty-million square yards of space. That’s more than three and a half miles in diameter.

It will have 32 wind turbines placed at ground level, each capable of creating 6.25 megawatts of electricity.

It will take 34 months to construct.

It will provide a total of 200 megawatts, which is enough to provide solar power in the form of electricity, for over 200,000 households.

The solar tower will create absolutely no carbon emissions, greenhouse gases, or other pollutants in its energy generation process. In other words, it is going to be 100% eco-friendly.

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Learn more about solar power and alternative energy at the author’s website on Solar Energy. You can also find a variety of Solar Panels and other solar-powered or wind-powered equipment at the Solar Power Store.

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About Global Warming And Knowing The Facts


Do you believe in aliens? That life from another planet far away came to Earth to begin life anew. For some, this is an explanation of global warming. Beings from another world found themselves faced with the global catastrophe of global warming and their environment began to fail.

They packed their bags and traveled to our planet. Is this fact or is it fiction? No one knows for sure. There is even thought that the issues about global warming are also applicable to the beliefs that other beings from other planets were forced to make themselves to Earth as their planet began to deteriorate, due to global warming.

the effects of global warming
It is all around us. It is on the weather stations. It faces us when we decide to purchase a new car or even a cleaning product. The real issues come when trying to learn global warming pollution. There is a lot of conflicting information on the internet and there is not one group that can agree on all aspects of the global warming climate change debate.

The first thing that can be agreed on is that global temperatures have risen over the past century. Granted, the rise in temperature has been only a degree or so but the issue is whether or not the temperatures of the Earth will continue to rise and the exact effect it will have on the environment. The debate about reduce global warming comes from conflicting evidence within the past.

Science has proven that global warming also occurred in or around prehistoric times. It is thought that a global catastrophe such as a meteor impacting Earth caused a temperature shift. Did it kill off the dinosaurs? Science does not know that this is factual.

Further complicating the issue about global warming is the political and industrial facets. These groups argue that there is not sufficient information about the effects of global warming to limit industrial emissions.

global warming greenhouse effect
When will we know the full facts about global warming and will the global warming issue be resolved anytime soon? Unfortunately the answer is no. There will continue to be studies performed and there will always be a measure of doubt clouding the minds of citizens around the world.

Perhaps, when enough data comes through, we will be able to make a determination based on scientific fact rather than theory. Until then we can continue to monitor the progress of scientists and try to do our part in conserving the environment.

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