Types of Solar Energy Solar Energy Conversion Methods
The sun emits enormous amount of radiation. When we refer to Types of Solar Energy we actually mean what are the different methods by which Sun Radiation is converted to other forms of energy. Sun radiation can be converted directly to electricity, can be converted to heat, and can be exploited by bio-chemical reactions. It can also be used directly for tanning, as long as one is aware to the hazards.
The Photovoltaic Effect | Direct Conversion to Electricity
Direct generation of electrical power is one of the most important types of solar energy conversion known. Photovoltaic Effect is the way to directly convert day light radiation (photons, light particles) into electricity (electrons, electricity particles). Solar panels are used extensively for residential solar power generation as well as for utility scale power plants. Better ways to produce economically more efficient solar panels are being researched by corporations and research institutes.
Big electrical Power Plants use mirrors or lenses to concentrate more sun radiation on solar panels to get more output power. The mirrors (or lenses) are tracking the sun as it changes its position in the sky
Solar Thermal | Converting Sun Radiation to Heat
The conversion of solar radiation to thermal energy (heating up water or air) is based on the greenhouse effect. Sun radiation in the visible wavelength goes through a transparent layer (glass or plastic), then absorbed in a black layer (black coated material) and heat it up. The black sheet absorber radiates the absorbed energy in the infrared wavelengths (what we humans feel as heat) toward the glass layer. Glass however is not transparent to infrared and the heat is trapped and can be delivered to water or air
Big electrical Power Plants use solar energy to generate steam, high temperature/high pressure water vapors to run steam electrical generators.
Bio-Chemical Sun Light Conversion
Among the different types of solar energy conversion there is one that nature support for billions of years. Photosynthesis is a well known bio-chemical reaction. Most plant life forms use photosynthesis; The sun provides the needed energy to process water and carbon dioxide in a reaction that produces carbohydrates. A byproduct is released oxygen that animals use for their internal combustion metabolism process. A lot of research is done to imitate photosynthesis in manmade environment or to use algae to produce fuel.
Often neglected, a sound building design can save a lot of money spent on artificial lighting by letting natural daylight to the building. Among the types of solar energy, natural daylight is generously provided by mother nature. Using large size windows and skylights can save the need for artificial lighting. Did you know that solar tubes can bring light to rooms that don't have windows?
Residential solar power generators are usually not bigger than 5 kW. Public buildings (schools, public and government offices) as well as business sector offices solar power generators are usually not bigger than 50 kW. Up to 50kW the solar electric panels dominate the market scene
The output power range of 100 kW to 1 MW is typical to communities that generate their own electricity, these solar plants are frequently combined with wind turbines and conventional small steam turbines
Utility scale power plants use types of solar energy such as optical concentrated solar (photoelectric technology) or Heliostats. Heliostats are mirrors that track the sun and reflect the sunlight onto a central collector. Heliostats are usually arranged in an array around a tower. The collector is mounted on the tower and produce steam at high temperature and high pressure to operate a steam turbine
Two limitations solar power plants have are:
The solar power plant takes a lot of land and is more efficient in sunny areas; this sunny land is available in desert area remote from the consumers. Therefore, new super high voltage power lines need to be built, a long and expensive process that draw a lot of objections by environmentalists and land owners.
There is still no large scale technology to store electrical power produced during day hours and to be used after sunset. Heliostats are more promising because technologies to store heat are more mature.