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A Solar pond is large-scale solar energy collector with integral heat storage for supplying thermal energy. A solar pond can be used for various applications, such as process heating, water desalination, refrigeration, drying and Solar power generation. Solar power describes a number of methods of harnessing energy from the light of the sun. ...
Desalination or desalinization refers to any of several processes that remove the excess salt and other minerals from water in order to obtain fresh water suitable for animal consumption or irrigation, and if almost all of the salt is removed, for human consumption, sometimes producing table salt as a by...
It has been suggested that Refrigerator be merged into this article or section. ...
Solar power describes a number of methods of harnessing energy from the light of the sun. ...
Description
A solar pond is simply a pool of water which collects and stores solar energy. It contains layers of salt solutions with increasing concentration (and therefore density) to a certain depth, below which the solution has a uniform high salt concentration. A girl in a swimming pool Water (from the Old English waeter; c. ...
When solar radiation (sunlight) is absorbed, the density gradient prevents heat in the lower layers from moving upwards by convection and leaving the pond. This means that the temperature at the bottom of the pond will rise to over 90ºC while the temperature at the top of the pond is usually around 30ºC. The heat trapped in the salty bottom layer, and can be used for many different purposes, such as the heating of buildings, industrial hot water or to drive a turbine for generating electricity.
There are 3 distinct layers of water in the pond:
- The top layer which has a low salt content
- The bottom layer which has a high salt content.
- An intermediate insulating layer with a salt gradient, which establishes a density gradient that prevents heat exchange by natural convection.
Brine is water saturated or nearly saturated with salt. ...
Convection is the transfer of heat by currents within a fluid. ...
Advantages The approach is particularly attractive for rural areas in developing countries. Very large area collectors can be set up for just the cost of the clay or plastic pond liner. A developing country is a country with low average income compared to the world average. ...
Disadvantages The system is however relatively difficult to maintain. - The salt gradient is very delicate and is easily upset by wind.
- The pond can foul up with algea
- The liner can spring a leak
- The evaporated surface water needs to be constantly replenished,
- The accumulating salt crystals have to be removed and can be both a valuable byproduct and a problem.
The algae (singular is alga) comprise several different groups of living things that produce energy through photosynthesis. ...
A magnified crystal of a salt (halite/sodium chloride) In chemistry, a salt is any ionic compound composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. ...
Efficiency The energy obtained is in the form of low grade heat of 70-80°C compared to a 20°C ambient temperature, which has an upper Carnot-cycle extractable efficiency of 1-(273.15+20)/(273.15+80)=15%. By comparison a solar concentrator system with molten salt delivering high grade heat at 800°C would be able to convert 73% of absorbed solar heat into useful work, and be forced to divest only 27% as waste heat to the cold temperature reservoir (ambient air.) A heat engine is an engine that uses heat to produce mechanical work by carrying a working substance through a cyclic process. ...
Development Further research is aimed at addressing the problems, such as the development of membrane ponds. These use a thin permeable membrane to separate the layers without allowing salt to pass through.
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