Solar Basics:

There are several ways to use the sun as an energy source:

Passive Solar Design

Passive solar refers to design considerations in structures that take advantage of the sun’s movement through the sky in order to make a building more energy efficient. As an example, a building constructed with windows facing the sun should have shading structures (awnings, roof extensions, etc) that are placed in such a way as to reduce the amount of sunlight entering the building in the summer, but allow direct sunlight to pass into the building in the winter.
Solar Thermal Heating

When sunlight strikes a dark surface, a great deal of energy is absorbed in the form of heat. The surface heats up – just like a car hood on a sunny day. Solar thermal heating systems use this to heat a structure by placing many dark-colored plastic tubes in direct sunlight. Water is then pumped through the tubes where it absorbs heat from the sun. The heated water is then circulated through the structure where it radiates heat into the interior environment.

The sun’s energy can also be transformed into electricity. By taking advantage of the basic physical properties of several specific elements, photovoltaic cells generate electricity when they are exposed to direct sunlight. This electricity can then be used immediately or stored (typically in batteries) to do work at a later time. Photovoltaics is technically the most complex way to use the sun’s energy (and often the most expensive), but it is also the method that requires the least amount of adaptation to benefit everyday life.

History of PV:

Ever since 1873 when a British scientist named Willoughby Smith noticed that selenium became more conductive as it was exposed to light, the field of photovoltaics has been growing in scope and innovations. The first solar cell was developed in 1880 and Albert Einstein even offered up an explanation as to how photovoltaic cells work. However, it wasn’t until the 1950s, when Bell Laboratories began working with NASA to develop cells for use in space, that photovoltaics achieved any real mainstream attention.

How Solar Panels Work:

A solar module (or panel as it is commonly referred to) is made up of many smaller cells that are connected to each other to achieve a desired electrical effect. Each cell is typically made primarily of silicon. Injected into the silicon are other elements that react differently when exposed to direct sunlight. When sunlight strikes the cell, electrons move from one layer to another and electricity is produced. Each individual cell only produces a small amount of electricity, but when many cells are connected to form a module (panel), a useful amount is generated.

Why PV?

Solar power is clean. Once PV panels are installed, there are no emissions.. The cells do not burn anything, or chemically react with anything in order to transform energy. They sit there quietly working as long as the sun is shining. In fact, some solar module manufacturers now state that their panels generate the same amount of energy it takes to produce the module in about 1 year. That means that for the rest of the life of the module they produce energy above and beyond the energy it took to manufacture them – with little or no maintenance required. Many manufacturers warranty their panels to produce 90% of the nameplate power after 25 years, with useful lives well beyond 30 years.
Solar power is quiet. The components of the average system have no moving parts, so the system works diligently without anyone even realizing it. Also, because there are no moving parts, the systems rarely require anything more than a simple checkup and cleaning.
Solar power, and other renewable energy resources, can reduce our dependence on foreign energy resources like petroleum. We have the capacity within our own borders to produce the energy we need, and do it without succumbing to political pressures in foreign lands.
The countries of the world that have installed the most solar power producing equipment are Germany, Japan, the United States, and Spain. Germany has about twice as much installed as Japan, and Japan has twice as much as Spain and the US. Considering the physical size of the United States, its technological prowess, and the large amounts of sunlight available for use in photovoltaics (PV) throughout the country, it is hard to believe that other (much smaller) countries have so much more PV installed.

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