The ability to utilize the sun’s energy due to the optimal distance between the sun and the earth is what has created the magic of life on earth. It is no wonder the solar energy is the factor that drives biotic life and abiotic energy in the form of winds, the water cycle, the tidal waves and all other natural energy sources on earth. 174 petta watts of solar radiation is being received on earth and the atmospheric insulation reflects 30% of this back in to space, while the rest is absorbed by the land masses, clouds and water bodies on the earth. The energy from solar sources reaching the earth is estimated to be 3,850 Zetta Joules per year and it is said that this is more energy in one hour than the world can consume in an entire year. The primary solar energy and the secondary energy that solar energy can be produced, viz; wind energy, biomass energy and hydropower are together capable of becoming a renewable energy source, with a capacity to meet 99.97% of energy needs. The energy if harnessed would be twice the amount we recover from non-renewable sources like fossil fuels.
Current technology to utilize the immense amounts of solar power is of two types- passive active methods.
The passive methods are otherwise classified as, “supply side technology,” as technology is aimed at reducing the use of other types of energy. Here materials with good thermal properties and/or spaces are designed in such a way that wherever possible, the sun’s energy is used for lighting, natural air circulation is maximized, spaces are positioned in reference to the sun’s position and so on. If this sounds like an ancient technique-it is. The passive methods to make buildings utilize solar energy by various methods have been found in Greek, Chinese, Indian and many other architecture types in the ancient world. In India, an entire branch of science called, “vasthu sastra,” has been dedicated to energy efficiency in buildings, while the Chinese call this balance of, “Chi.”
Other methods of passive used in modern times to minimize heat concentrated in small urban areas (Urban Heat Island-UHI), usually due to use of highly heat absorbing materials like asbestos, would be to paint the materials white and to plant trees around the area. This has found to reduce heat by 3C.
Active methods consist of capturing solar energy via photovoltaic panels, pumps, fans and Concentrated Solar Power (CSP) technologies, which essentially convert solar energy into electrical energy. Prevailing oil prices usually affected the development of technologies to create active means of capturing and using solar energy.
Photovoaltiac cells (PV) are solar cells that convert solar energy into direct current (photovoltaic effect). The first known PV was build from selenium in the year 1880. In 1954, silicon, a more efficient material replaced selenium (absorbs 5%-6% of incident energy) for PV cells. Until the 1970s, this technology was prohibitively high for use on earth, while being very successful to power space satellite missions (when chemical batteries expire) and in telecommunications. It was in the ‘70s, when oil prices spiked that a viable solar power technology was created for terrestrial use which powered remote houses 9without using the power grid), railroad crossings, oilrigs and so on in the USA. Today, Japan and Germany have taken the lead in creating and utilizing the photovoltaic technology. Germany has become the predominant market for photovoltaic cells and has 4150MW of installed PV capacity in the country. Many other countries, notably Spain have also followed suit.
Concentrated Solar Power systems concentrate on focusing a large area of sunlight into a mall beam by the use of a system of mirrors and lenses. Linear parabolic reflectors are also used widely to focus sunlight on a receiver placed along its focal length. The most efficient system to concentrate solar power is the parabolic dish system that tracks sunlight along tow axii, which is absorbed by the receiver. The heat received is transmitted to heat a working fluid and drive turbine to produce electricity. In the case of Stirling solar dishes, a combination of parabolic reflectors and Stirling heat engines work together to generate electricity. Stirling solar dishes are superior to photovoltaic cells in that they are more efficient and have a longer life (25 years minimum). Additionally there are solar power towers that concentrate light on a receiver on top of a tower. This is less advanced but more efficient and is better suited to store energy.
Many other experimental technologies to utilize solar power are also being developed to make solar power an economic, sustainable and easy to use option.
One of this is a solar updraft tower- a solar chimney or tower extending from a green house. The heated gases in the green house are funneled into a central tower. The hot air turns a turbine to produce electricity. A Solar pond is another experimental technology, which takes advantage of the fact that salts in water absorb and retain solar energy. The concentration of salts in the bottom the lake is high, leading to temperatures as high as 90 degrees Celsius (in some places) that is capable of offering solar-electricity efficiency of 2%. Thermoelectric or thermovoltaic devices convert temperature differences in two different types of materials into electrical energy.
While generation of solar powered electricity is one aspect, storage of energy is another area that needs to be addressed for solar energy becomes more commonplace. This is important because solar energy is an interrupted source of energy and is subject to weather conditions. Thermal mass systems, comprising of easily available materials like water, stones or earth becomes the medium for absorbing and storing solar energy. Paraffin wax and molten salts can also be used to effectively store solar energy. They are readily available, economic, have a good specific heat capacity and are compatible with conventional power systems. Off-grid PV systems also store power in rechargeable batteries. Pumped storage hydroelectricity stores excess energy in the form of water pumped from lower to higher elevation reservoirs, which is released when more electricity is required.
Solar power has been used in many important areas to energize systems. In Horticulture & agriculture, the technique of capturing and retain solar energy in green houses to nurse plants all year round is one of the oldest uses of solar energy. Solar lighting systems are the most common methods to illuminate common area like walk ways in most countries. Interior lighting by ducting solar light into buildings and thing Systems are Hybrid lighting systems are being increasingly adopted to save energy. Thermal heating using solar power has been used for heat required in processes as well as for thermal and space heating. Passive methods using thermal masses for bringing down energy consumption in HVAC systems can be used efficiently to absorb heat to cool areas as well as release heat to warm them up. Solar cooking in to cook, pasteurize and dry food is widely used. Here, the reflected light from polished surfaces is focused on the receiver that transmits the energy to the device that performs the function. Disinfections of water without the use of chemicals but by subjecting water to long hours (2-6 hours) under solar energy are another method of solar energy use. The WHO has ratified this type of disinfection. Producing thermal energy using active solar technology to drive industrial processes as well as driving vehicles is being used and further experimented.
The ability to utilize the sun’s energy due to the optimal distance between the sun and the earth is what has created the magic of life on earth. It is no wonder the solar energy is the factor that drives biotic life and abiotic energy in the form of winds, the water cycle, the tidal waves and all other natural energy sources on earth. 174 petta watts of solar radiation is being received on earth and the atmospheric insulation reflects 30% of this back in to space, while the rest is absorbed by the land masses, clouds and water bodies on the earth. The energy from solar sources reaching the earth is estimated to be 3,850 Zetta Joules per year and it is said that this is more energy in one hour than the world can consume in an entire year. The primary solar energy and the secondary energy that solar energy can be produced, viz; wind energy, biomass energy and hydropower are together capable of becoming a renewable energy source, with a capacity to meet 99.97% of energy needs. The energy if harnessed would be twice the amount we recover from non-renewable sources like fossil fuels.
Current technology to utilize the immense amounts of solar power is of two types- passive active methods.
Other methods of passive used in modern times to minimize heat concentrated in small urban areas (Urban Heat Island-UHI), usually due to use of highly heat absorbing materials like asbestos, would be to paint the materials white and to plant trees around the area. This has found to reduce heat by 3C.
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Concentrated Solar Power systems concentrate on focusing a large area of sunlight into a mall beam by the use of a system of mirrors and lenses. Linear parabolic reflectors are also used widely to focus sunlight on a receiver placed along its focal length. The most efficient system to concentrate solar power is the parabolic dish system that tracks sunlight along tow axii, which is absorbed by the receiver. The heat received is transmitted to heat a working fluid and drive turbine to produce electricity. In the case of Stirling solar dishes, a combination of parabolic reflectors and Stirling heat engines work together to generate electricity. Stirling solar dishes are superior to photovoltaic cells in that they are more efficient and have a longer life (25 years minimum). Additionally there are solar power towers that concentrate light on a receiver on top of a tower. This is less advanced but more efficient and is better suited to store energy.
While generation of solar powered electricity is one aspect, storage of energy is another area that needs to be addressed for solar energy becomes more commonplace. This is important because solar energy is an interrupted source of energy and is subject to weather conditions. Thermal mass systems, comprising of easily available materials like water, stones or earth becomes the medium for absorbing and storing solar energy. Paraffin wax and molten salts can also be used to effectively store solar energy. They are readily available, economic, have a good specific heat capacity and are compatible with conventional power systems. Off-grid PV systems also store power in rechargeable batteries. Pumped storage hydroelectricity stores excess energy in the form of water pumped from lower to higher elevation reservoirs, which is released when more electricity is required.
Solar power has been used in many important areas to energize systems. In Horticulture & agriculture, the technique of capturing and retain solar energy in green houses to nurse plants all year round is one of the oldest uses of solar energy. Solar lighting systems are the most common methods to illuminate common area like walk ways in most countries. Interior lighting by ducting solar light into buildings and thing Systems are Hybrid lighting systems are being increasingly adopted to save energy. Thermal heating using solar power has been used for heat required in processes as well as for thermal and space heating. Passive methods using thermal masses for bringing down energy consumption in HVAC systems can be used efficiently to absorb heat to cool areas as well as release heat to warm them up. Solar cooking in to cook, pasteurize and dry food is widely used. Here, the reflected light from polished surfaces is focused on the receiver that transmits the energy to the device that performs the function. Disinfections of water without the use of chemicals but by subjecting water to long hours (2-6 hours) under solar energy are another method of solar energy use. The WHO has ratified this type of disinfection. Producing thermal energy using active solar technology to drive industrial processes as well as driving vehicles is being used and further experimented.
