Solar power

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Suraj yadav, mechanical er.ing sem 6th , g\e\c, b\v\n.
Solar still:

A solar still is a low-tech way of distilling water, powered by the heat of the sun (more precisely, the heat & humidity of the soil, and relative cool of the plastic). Two basic types of solar stills are box, and pit. In a solar still, impure water is contained outside the collector, where it is evaporated by sunlight shining through clear plastic. The pure water vapor (and any other included volatile solvent) condenses on the cool inside plastic surface and drips down off of the weighted low point, where it is collected and removed. The box type is more sophisticated.

Solar stills are used in cases where rain, piped, or well water is impractical, such as in remote homes or during power outages. SOLAR POWER.
solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power(CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics converts light into electric current using the photoelectric effect. Solar refrigeration: Solar-powered refrigerators are most commonly used in the developing world to help mitigate poverty and climate change. By harnessing solar energy, these refrigerators are able to keep perishable goods such as meat and dairy cool in hot climates, and are used to keep much needed vaccines at their appropriate temperature to avoid spoilage. The portable devices can be constructed with simple components and are perfect for areas of the developing world where electricity is unreliable or non-existent. [1] Other solar-powered refrigerators were already being employed in areas of Africa which vary in size and technology, as well as their impacts on the environment. The biggest design challenge is the intermittency of sunshine (only several hours per day) and the unreliability (sometimes cloudy for days). Either batteries (electric refrigerators) or phase-change material is added to provide constant refrigeration

Suraj yadav, mechanical er.ing sem 6th , g\e\c, b\v\n.
Portable Solar Powered Fridge
A Portable solar powered fridge has been produced for use in the developing world. The basic design uses the principle of evaporation.[10] The fridge is solar powered, but does not require solar panels, and can be made from basic household material lowering the cost and making access to the developing world easier. Without using any power the fridge can keep perishable at a temperature of 6 degrees Celsius for days.

How it works
The refrigerator employs a combination of heat conduction and convection, requires no electricity and can be made for commonly available material such as cardboard, sand and recycled metal.[12] The device is composed of two cylinders. The inner metal cylinder is fitted inside the outer cylinder which can be made from what ever the person has access to including wood or plastic.[13] Space is left between the inner and outer chamber to be filled with organic material which can include sand, wool or soil that is then saturated with water. As heat from the sun evaporates the water, the inner chamber cools reducing and maintaining the temperature at 43 °F (6 °C).[14]

Usage
The portable solar fridge is used in areas of Africa such as Zambia, Namibia, and South Africa in areas where electricity is often not readily accessible to help preserve perishable foods such as meat and dairy, however, is not yet being used for vaccines.[15] It is easily transported and reduces negative environmental impacts but is limited by size and requires the availability of water Solar heliostat:

A heliostat (from helios, the Greek word for sun, and stat, as in stationary) is a device that includes a plane mirror which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun's apparent motions in the sky. The target may be a physical object, distant from the heliostat, or a direction in space. To do this, the reflective surface of the mirror is kept perpendicular to the bisector of the angle between the directions of the sun and the target as seen from the mirror. In almost every case, the target is stationary relative to the heliostat, so the light is reflected in a fixed direction. Most modern heliostats are controlled by computers. The computer is given the latitude and longitude of the heliostat's position on the earth and the time and date. From these, usingastronomical theory, it calculates the direction of the sun as seen from the mirror, e.g. its compass bearing and angle of elevation. Then, given the direction of the target, the computer calculates the direction of the required angle-bisector, and sends control signals to motors, often stepper motors, so they turn the mirror to the correct alignment. This sequence of operations is repeated frequently to keep the mirror properly oriented. Large installations such as solar-thermal power stations include fields of heliostats comprising many mirrors. Usually, all the mirrors in such a field are controlled by a single computer. There are older types of heliostat which do not use computers, including ones that are partly or wholly operated by hand or by clockwork, or are controlled by light-sensors. These are now quite rare.

Suraj yadav, mechanical er.ing sem 6th , g\e\c, b\v\n.
Heliostats should be distinguished from solar trackers or sun-trackers, which always point directly at the sun in the sky. However, some older types of heliostat incorporate solar trackers, together with additional components to bisect the sun-mirror-target angle. Nowadays, most heliostats are used for daylighting or for solar power generation. A few are used experimentally, or to reflect motionless beams of sunlight into solar telescopes.

In some countries, heliostats are sometimes used in solar cooking. Before the availability of lasers and other electric lights, heliostats were widely used to produce intense, stationary beams of light for scientific and other purposes Copy write: suraj yadav

Solar chimney power plant: The solar updraft tower is a renewable-energy power plant. It combines three old and proven technologies: thechimney effect, the greenhouse effect and the wind turbine. Air is heated by sunshine and contained in a very large greenhouse-like structure around the base of a tall chimney, and the resulting convection causes air to rise up the updraft tower. This airflow drives turbines, which produce electricity.

Suraj yadav, mechanical er.ing sem 6th , g\e\c, b\v\n.
The generating ability of a solar updraft power plant depends primarily on two factors: the collector area and the chimney height. With a larger collector area, a greater volume of air is warmed to flow up the chimney; collector areas as large as 7 kilometres (4.3 mi) in diameter have been considered. With a larger chimney height, the pressure difference increases thestack effect; chimneys as tall as 1,000 metres (3,281 ft) have been considered. Heat can be stored inside the collector area greenhouse to be used to warm the air later on. Water, with its relatively high specific heat capacity, can be filled in tubes placed under the collector, increasing the energy storage as needed.[1] Turbines can be installed in a ring around the base of the tower, with a horizontal axis, as planned for the Australian project and seen in the diagram above; or—as in the prototype in Spain—a single vertical axis turbine can be installed inside the chimney. Carbon dioxide is emitted only negligibly[citation needed] while operating, but is emitted more significantly during manufacture of its construction materials, particularly cement. Net energy payback is estimated to be 2–3 years.[1] A solar updraft tower power station would consume a significant area of land if it were designed to generate as much electricity as is produced by modern power stations using conventional technology. Construction would be most likely in hot areas with large amounts of very low-value land, such as deserts, or otherwise degraded land. A small-scale solar updraft tower may be an attractive option for remote regions in developing countries.[2][3] The relatively low-tech approach could allow local resources and labour to be used for its construction and maintenance.

Solar plate collector

Suraj yadav, mechanical er.ing sem 6th , g\e\c, b\v\n.

A solar furnace :
A solar furnace is a structure that captures sunlight to produce high temperatures, usually for industry. This is done with a curved mirror (or an array of mirrors) that acts as a parabolic reflector, concentrating light(Insolation) onto a focal point. The temperature at the focal point may reach 3,500 °C (6,330 °F), and this heat can be used to generate electricity, melt steel, make hydrogen fuel or nanomaterials. The term "solar furnace" has also evolved to refer to solar concentrator heating systems using parabolic mirrorsor heliostats where 538 °C (1,000 °F) is now commonly achieved. The largest solar furnace is at Odeillo in thePyrenees-Orientales in France, opened in 1970. It employs an array of plane mirrors to gather sunlight, reflecting it onto a larger curved mirror. The rays are then focused onto an area the size of a cooking pot and can reach 3,500 °C (6,330 °F), depending on the process installed, for example:   about 1,000 °C (1,830 °F) for metallic receivers producing hot air for the next generation solar towers as it will be tested at the Themis plant with the Pegase project[1] about 1,400 °C (2,550 °F) to produce hydrogen by cracking methane molecules[2

The solar furnace principle is being used to make inexpensive solar cookers and solar-powered barbecues, and for solar water pasteurization.[8][9][10] A prototype Scheffler reflector is being constructed in India for use in a solar crematorium. This 50 m² reflector will generate temperatures of 700 °C (1,292 °F) and displace 200-300 kg [11] of firewood used per cremation. It has been suggested that solar furnaces could be used in space to provide energy for manufacturing purposes. Their reliance on sunny weather is a limiting factor as a source of renewable energy on Earth but could be tied to thermal energy storage systems for energy production through these periods and into the night

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