Principle Of Solar Energy: The Purpose Of Solar Energy

1.1 SOLAR ENERGY :

Solar Energy is the resultant outcome of thermonuclear reactions of fusion from hydrogen into helium taking place in the sun. These thermonuclear reactions release huge energy and radiate the energy to space continuously. This kind of energy which is continuous and eternal is available as solar energy. The average intensity of solar radiation on the earth circumnavigate is 1367kW/m2, and the earth's equatorial circumference is 40,000km, so it can be worked out that the energy the earth obtains is up to 173,000TW. The energy on earth, including wind energy, hydropower, ocean thermal energy, wave energy, bio energy and some tidal energy all come from the sun. Even the fossil fuels on earth (such

Some 2,000 years ago, Chinese people knew how to use a four-side steel mirror to focus the sunlight for making a fire, and they used solar energy to dry agricultural products. In modern times, the use of solar energy becomes widely popular, which includes solar thermal utilization, solar photovoltaic utilization and solar photochemical utilization etc., Solar power is the conversion of sunlight into electricity.

1.2 Principle of Solar oven :

The basic purpose of a solar oven is to heat things up cook food, purify water, and sterilize instruments - to mention a few. A solar box cooks because the interior of the box is heated by the energy of the sun.

Figure 1.1

The key component of all solar system is the solar collector. This is a device which absorbs the solar radiation from sun converts into heat and transfers this heat to a fluid ( air, water, oil ) passes through the collector. The solar energy collected is carried from the circulating fluid either directly to the hot water or to a thermal energy storage tank from which can be utilized for use at night or cloudy days. There are basically two types of solar collectors: non-concentrating/stationary and concentrating. A non-concentrating collector has the flat surface for intercepting and for absorbing solar radiation, where a sun-tracking concentrating solar collector usually has concave reflecting surfaces to intercept and focus the sun’s radiation to a smaller receiving surface, by means of increasing the radiation flux.

Two types of collectors are available:

1. Non-concentrating/stationary collector

2. Concentrating collector

2.2 STATIONARY COLLECTORS