Solar Energy and Solar Thermal Energy

Solar thermal energy is a technology for harnessing solar energy for thermal energy and it is different from photovoltaics, which convert solar energy directly into electricity. There are many applications of solar thermal energy such as drying, heating and water distillation.

Many solar thermal technologies have existed for centuries and have established manufacturing bases in many sun-rich countries. Manufacturing can be done on a small scale without using expensive equipment. In 2008 solar thermal energy industry in Europe has grown over 60%.

The USA Energy Information Administration defined solar thermal collectors as:

• low temperature collectors- flat plates used to heat swimming pools
• medium-temperature collectors- usually flat plates used for creating hot water for residential and commercial use
• high temperature collectors- concentrate sunlight using lenses or mirrors and are used for electric power production

Solar thermal technology is used for domestic water heating and provides large quantities of hot water or space heating for nonresidential buildings.

There is a lot of different kinds of solar water heaters and the simplest is a piece of black plastic pipe, filled with water, and laid in the sun for the water to heat up. A solar collector is a series of black pipes, sitting inside an insulated box fronted with a glass panel.

Solar thermal energy can be used in drying grains, coffee, tobacco, fish and fruits. It is environmentally friendly, cost effective and improves the quality.

It raises the heat of the product and at the same time passes air through the compartment to remove moisture.

Solar distillation is necessary in areas that clean water is not common. Its main aim is to provide people with purified water. Basic solar stills can be used to remove fluoride and salts to produce drinking water.

Solar thermal power plants obtain their energy input through concentrated solar radiation and then convert it to high-temperature steam or gas to drive a turbine or motor engine. No pollutants are emitted in producing the electricity.