Sunlight focused by a large array of mirrors or lenses onto a collector is called concentrated solar power. The concentrated sunlight can also be used to heat specialized energy-conducting fluids to generate energy in a conventional electrical plant. Read on to learn about concentrated solar power and its applications.
Concentrated Solar Power Towers
Most often a concentrated solar power array uses standard solar panels, whose surfaces both absorb and reflect sunlight. The group of panels is aligned so that they all focus their energy on a tower in their midst, called the solar receiver. The solar receiver heats a fluid, usually seawater, to power turbines that generate electrical energy. Because of the density of seawater, these power towers are among the most efficient at energy storage. The Middle Eastern and European consortium called Desertec plans to use concentrated solar power towers to produce electricity and desalinated water for the driest regions of North Africa and Mediterranean Europe.
Another common format is to use a solar collector shaped like a parabolic trough to focus and concentrate the sunlight along a receiver tube down the center of the parabola. The energy collected heats a dense fluid such as molten salt which sends this energy to a power generator.
Parabolic Stirling Dishes
Solar power parabolic dishes have a single receiver that superheats fluid and sends it to a Stirling engine to create electricity. These dishes have the highest ratio of energy collected to electricity generated among all concentrated solar power facilities. The Middle Eastern and European consortium called Desertec plans to use concentrated solar power towers to produce electricity and desalinated water for the driest regions of North Africa and Mediterranean Europe.
Solar chimneys have a glass enclosure at their base which superheats the air in a central chimney. This hot air drives an air turbine to generate electricity. These are among the least expensive concentrated solar power plants, and could be constructed easily in developing countries.
Luminous Solar Concentrators
These concentrators improve the energy collection and electricity production of photovoltaic solar panels tremendously, by enabling the absorption of much higher levels of solar photons. Solar concentrators are also used as tracking devices to keep the solar power arrays pointed into the most direct sunlight.
Purpose of Concentrated Solar Power
Concentrated solar power enables the superheating of steam to drive turbines, or to superheat fluid to transfer thermal energy to a power plant. The amount of sunlight collected increases dramatically in all types of concentrated solar power arrays. Concentration of solar power makes solar electricity generation more viable even in areas at greater than 40 degrees north or south of the equator. It also increases the conversion efficiency of solar energy to electricity, from the average 12 to 18% up to 42% in recent laboratory tests.
Concentrated Photovoltaic Energy and Thermal Heat Power
The combination of concentrated photovoltaic energy (CPV) and thermal heat generation can heat both water and air in individual homes. A CPV plus thermal system can bring energy efficiency to between 40 and 50%, much better than the 20% efficiency of photovoltaic solar panels alone.