Solar energy has been harnessed by man since time memorial. Man has made use of the light and the heat coming from the sun. Solar technologies have changed since then and they can be grouped into the active and the passive solar technologies. Some of the solar technologies include solar structural design, artificial photosynthesis and photovoltaic.Solar energy is the way forward in solving the world energy crisis. It has many advantages compared to the conventional sources of energy because it is a clean source of energy, therefore it does not contribute to environmental pollution, and it is abundant source of energy as the sun contributes to ninety percent of the energy in the world. Solar energy is a source of inexpensive that has the ability to secure the nature of energy security in many nations and has the ability to reduce the cost of fossil fuels considerably.
Thermal collectors and photovoltaic panels are examples of active solar techniques whereas the passive solar techniques include adjusting the direction a building is facing relative to the sun, selecting building material that have the right thermal conditions to allow for certain conditions and the scheming structures that allow for free circulation of air.
Solar energy can be used for water boiling, space heating, spacing cooling and heat generation for manufacturing processes. The water heating system is dependent on the on the latitudes relative to the sun. The water heating system is capable of raising the temperature of water up to 60 degrees Celsius. The most used water heating systems include evacuated tube collectors and the glazed flat plate collectors. The evacuated tube collectors can achieve heat conversion efficiencies of 44 per cent while the glazed flat collectors have an efficiency of 21 per cent.
Solar energy is applied passively in space heating, cooling and aeration systems. They make use of a thermal mass which also refers to a material that can be used to collect heat. The material absorbs solar energy. They include stone, cement and water mainly. They are used to absorb energy during the day time and release it in the night for heating purposes.
Solar energy is also used in water purification. This technique makes use of evaporation or distillation. The project consists of a collection area where the saline water is stored ready for evaporation. There are two types of designs for solar purifiers and they include the individual still design and the greenhouse design.
Solar energy is applied in cooking. The solar cookers can be grouped into the box cooker, the reflectors cooker and the panel cookers. The most fundamental cookers is made up of the insulated cover and the clear lid. It is most effective when used in conditions that are clear and the highest temperature they can achieve is 150 degrees Celsius. Solar energy is applied in drying seeds and while pasteurizing milk.
Solar energy is converted directly into electricity using photovoltaic cells or concentrated solar power. The concentrated solar power makes use of lenses or mirrors to concentrate sunlight into a small beam. The photovoltaic concerts solar rays to electric current using the photoelectric effect.