What is solar energy?
Solar energy is energy obtained from the sun. When we talk about solar energy we usually mean the radiation that reaches us directly from the sun. There are many ways in which we can use the energy that is captured. These fall into one of two categories of application – solar thermal and solar electric. In solar thermal systems, solar energy can be converted to heat and used directly or stored. The evaporation of water for salt production or water distillation are common examples of solar thermal applications. The most obvious example of stored solar heat is the familiar solar hot water service. Solar electric systems produce electricity directly from photovoltaic cells.
We have always used the energy of the sun as far back as humans have existed on this planet. As far back as 5,000 years ago, people “worshipped” the sun. Ra, the sun-god, was considered the first king of Egypt. In Mesopotamia, the sun-god Shamash was a major deity and was equated with justice. In Greece there were two sun deities, Apollo and Helios. The influence of the sun also appears in other religions – Zoroastrianism, Mithraism, Roman religion, Hinduism, Buddhism, the Druids of England, the Aztecs of Mexico, the Incas of Peru, and many Native American tribes. We know today, that the sun is simply our nearest star. Without it, life would not exist on our planet. We use the sun’s energy every day in many different ways. When we hang laundry outside to dry in the sun, we are using the sun’s heat to do work – drying our clothes. Plants use the sun’s light to make food. Animals eat plants for food. Decaying plants and organisms hundreds of millions of years ago produced the coal, oil a
A. Solar Energy is produced by photovoltaic solar panels that create DC (direct current) voltage that can be connected and stored in batteries. This power is usually inverted to AC (alternating current) voltage, which can supply the necessary electricity to be used to power some or all of a homes electrical systems.
Plants have been using the energy from the sun for billions of years. Until recently, however, this energy has been available only indirectly to humans via the energy we harvest in the form of everything from fossil fuels to plants to wind power (all solar energy derivatives). Today, as environmental awareness and rising oil prices put pressure on society, the potential of emerging solar energy technologies that directly harness the nearly limitless energy of the sun is increasingly desirable and economically feasible. Harnessing Solar Energy Harnessing solar energy involves both the direct use of the radiated heat as well as its conversion to electricity in the most efficient way possible. There are three categories that define every type of solar energy technology. First, passive solar collection begins with the design of the building and includes optimal location, windows facing south, walls that absorb heat and light, and plenty of insulation. The heat and light that is collected i
Solar energy is the energy that comes to us from the sun. We can harness that energy and put it to use in our everyday lives. The technologies we use to transform the sun s energy are often divided into three categories: • Passive Solar Energy • Active Solar Energy • Photovoltaic (Electrical) Solar Energy Passive Solar Energy is a commonly used term that can have a wide variety of meanings. It is often used to refer to certain building practices that take advantage of the sun s energy with nothing other than proper building design and construction techniques. For example, on a bright sunny winter day, you will notice that rooms in your house, with south facing windows, will be nice and warm, even if it s cold outside. South-facing windows are one way of collecting solar energy passively . There are passive techniques that can be used to take advantage of solar energy with windows, walls, roofs and even landscaping. A properly designed, constructed and insulated home or office building
