عنوان مقاله [English]
Nowadays, increasing energy demand is one of the challenges that confront the humankind. Limitation of fossil fuels source clarifies the importance of new and renewable energies. Renewable energy is derived from natural processes that are replenished constantly. Solar energy is one of them. The sun contains extreme amount of energy. The solar energy is not uniformly distributed on the earth’s surface. Insulation is a measure of solar radiation energy received on a given surface area and recorded during a given time. Little contribution of solar energy in the world energy usage is due to the distribution on a very wide area and periodic variations. Nevertheless, the solar energy is safe and free, so it is the best alternative for fossil fuels. Modern technologies serve as approaches to make it more applicable and pervasive.