SOLAR POND

By

P. Vamsi Krishna 08BK1A0247

INTRODUCTION

INCREASING DEMAND FOR ENERGY

SOLAR POND

A solar pond is a pool of saltwater which acts as a large-scale solar thermal energy collector with integral heat storage for supplying thermal energy.

LAYERS OF A SOLAR POND

Top layer with low salt content

Intermediate layer for insulation

Bottom layer with high salt content

WORKING PRINCIPLE

Tendency of water to raise upwards when heated.

Restriction of this tendency by dissolving salt in the bottom layer.

LAYOUT OF A SOLAR POND

TYPES OF SOLAR PONDS

Nonconvecting ponds, which reduce heat loss by

preventing convection from occurring within the

pond.

Convecting ponds, which reduce heat loss

by hindering evaporation with a cover over the

surface of the pond.

CONVECTING SOLAR PONDS

These ponds are convective and prevents evaporation.

  Generally shallow.

  Pure water is enclosed in a bag.

  The water in the bag is heated by the sun during the day.

  Absorption is maximized by a dark bottom, insulation below, and glass or plastic on top. 

Heat loss is minimized.

NON CONVECTING SOLAR PONDS

 A solar salt pond contains two convective layers and a middle non convective layer. 

The Non convective layer traps the heat.   

A heat transfer liquid is pumped through a heat exchanger placed on the bottom of the pond, removing the energy. . 

The bottom layer always remains denser than the upper layers.. 

Brine concentration

ELECTRICITY GENERATION

An Organic Rankine Cycle Engine power generator is used to convert the energy from the pond to solar energy. 

Evaporation of hot water. 

This drives a turbine, which in turn produces electricity. 

The gas is then condensed and recycled once it has been cooled.

ADVANTAGES

The approach is particularly attractive for rural areas in developing countries.

No need of a separate collector for this thermal storage system.

Heat energy is provided without burning fuel, thus reducing pollution.

Conventional energy resources are conserved.

Diffuse radiation (cloudy days) is fully used.

DISADVANTAGES

The evaporated surface water needs to be constantly replenished.

The accumulating salt crystals have to be removed and can be both a valuable by-product and a maintenance expense.

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.

APPLICATIONS

Generating heat

Generating electricity

Water desalination

Thermal energy storage

EXAMPLES

BEIT HAARAVA POND BHUJ SOLAR POND

CONCLUSION

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.

Because of the current availability of cheap fossil fuels, solar pond development has been limited.

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.

QUERIES . . . ?