Fossils fuels are depleting due to continuous use for various purposes. Scientist are trying to develop the use of renewable energy sources. Among these, solar energy provides the greatest promise for the mankind. Solar pond technology has made substantial progress in the last fifteen years. It is a device for both collecting and storing solar energy. Among the many type of solar ponds, the salt gradient non convecting solar pond is becoming popular.
The paper reviews the basic principle of solar ponds, its construction, working and the problems encountered in its operation. Some aspects of heat extraction from solar pond and its application have also been discussed. Solar pond technology has made considerable progress in the last fifteen years. The salinity gradient solar ponds are found to be more popular for collecting and storing solar energy. This device is found to be cost effective for low temperature process heat needs of industry. The major limitation is that temperature cannot exceed 950c. The generation of electricity using solar ponds is not economically viable yet. When higher temperatures can be achieved due to improvements in the technology, it will open up new applications of thermal energy from solar ponds..
Solar ponds can be effectively used as replacements in industries that use fossil fuel to generate thermal energy. Solar ponds can be used for process heating, refrigeration, water desalination, production of magnesium chloride, bromine recovery from bittern, enhancement of salt yield in salt farms. It will be the future energy source.
The sun is the largest source of renewable energy and this energy is abundantly available in all parts of the earth.
One way to tap solar energy is through the use of solar ponds. Solar ponds are large-scale energy collectors with integral heat storage for supplying thermal energy. It can be use for various applications, such as process heating, water desalination, refrigeration, drying and power generation.
Size - In the last 20 years, many salt gradient solar ponds varying in size from a few hundred to a few thousand square meters
Salt used - Normally sodium chloride salt is used in the solar pond. But the maximum temperature obtained in the natural brine solar pond is less than sodium chloride used solar pond.
Modes of heat extraction
Methods to improve performance
Use of plane mirror at the top portion of the solar pond
Higher water temperature was
obtained when the reflector is adjusted than the adjusting the orientation angle of the pond
Baffle plate is used for more thermal conductivity
Factors affecting performance
Water turbidity and bottom reflectivity
Wall shading effect
Effect of energy extraction
Aquaculture, using saline or fresh water
Fruit and vegetable canning industry
Water supply (for desalination)
EL PASO Solar Pond
Over 90 graduate and undergraduate students have been involved in the project, performing tasks ranging from construction to applied research. In addition, numerous students have done projects related to the pond, gaining valuable experience in equipment design and construction, lab techniques, problem solving, instrumentation, and documentation.
Advantages and disadvantages
Low investment costs per installed collection area.
Thermal storage is incorporated into the collector and is of very low cost.
Diffuse radiation (cloudy days) is fully used.
Very large surfaces can be built thus large scale energy generation is possible.
Expensive cleaning of large collector surfaces in dusty areas is avoided.
Solar ponds can only be economically constructed if there is an abundance of inexpensive salt, flat land, and easy access to water. Environmental factors are also important. An example is preventing soil contamination from the brine in a solar pond. For these reasons, and because of the current availability of cheap fossil fuels, solar pond development has been limited.
Solar pond is a device used for collecting and storing the solar energy.
The temperature, salinity and density of UCZ and LCZ are almost constant. Whereas,
in NCZ they are increasing with depth.
Mini solar pond can also be used for various thermal applications.
Heat can be extracted either batch mode or continuous mode from LCZ of the solar
Natural brine and fertilizer salts are used in the solar pond instead of sodium chloride.
Any basin absorbs calefaction from the sun. Normally, calefaction is absent as balmy baptize rises to the apparent and cools by evaporation. But baptize is a VERY poor aqueduct of calefaction and if this apportionment can be stopped, the calefaction can be trapped in the basal of the lake.