solar ponds

1. SOLAR PONDS
S.VIDYA SAGAR
11401053

2. CONTENTS
 INTRODUCTION
 TYPES OF SOLAR PONDS
 DISCRIPTION OF SALT GRADIENT SOLAR PONDS
 WORKING PRINCIPLE
 EXAMPLES
 ADVANTAGES
 DISADVANTAGES
 APPLICATIONS
 CONCLUSION
 REFERENCES

3. INTRODUCTION ::
•A solar pond is a large scale solar thermal
collector with an integrated arrangement
for storage of heated water
•Solar ponds are unique in their ability to
gather and store energy simultaneous

4. TYPES OF SOLAR PONDS ::
nonconvecti
Non
convective
solar ponds
Convective
solar ponds
There are two types of solar ponds
SOLAR PONDS

5. Non convective ponds ::
There are two main types of non convective ponds
Salt
gradient
ponds
Membrane
ponds
NON CONVECTIVE PONDS

6. DESCRIPTION OF SALT GRADIENT SOLAR PONDS ::
• Pond structure is 1 or 2 meters depth.
• A thick durable plastic liner is laid at the bottom of that pond,
materials used for the liner are
 High density polythene
 Low density polythene
 Woven polyester yarn
• Salts like magnesium chloride, sodium chloride or sodium
nitrate are dissolved in the water , the concentration varying
from 20 to 30 percent at the bottom to almost zero at the top.

7. • . In the salt-gradient ponds , dissolved salt is used to create layers of water
with different densities-the more salt, the denser water .Thus a solar pond has
three zones with the following salinity with depth :
1) Surface convective zone (SCZ)
2) Non-convective zone (NCZ)
3) Storage zone(or) lower convective zone (LCZ)
SURFACE CONVECTIVE ZONE(SCZ) ::
• SCZ has a thickness around 0.3 to 0.5 meters.
• SCZ has a low uniform concentration and temperature close to ambient
temperature.

8. NON CONVECTIVE ZONE (NCZ)::
• The non convective zone is much thicker and occupies more than half the
depth of the pond I.e. 0.9 to 1.2 meters .
• Both the concentration and the temperature increase with the depth .
STORAGE ZONE ( OR ) LCZ ::
• Storage zone or LCZ having a thickness of around 0.5 meters .
• Both the concentration and temp are constant in this zone.

10. WORKING PRINCIPLE ::
• When the sun rays contact the bottom of a shallow pool, they heat the
water adjacent to the bottom . When water at the bottom of the pool is
heated, it becomes less dense than the cooler water above it,
and convection begins. Solar ponds heat water by inhibits this
convection. This entire process is taking at storage zone (or) LCZ
• High-salinity water at the bottom of the pond does not mix readily with
the low-salinity water above it, so when the bottom layer of water is
heated, convection occurs separately in the bottom and top layers, with
only mild mixing between the two. This greatly reduces heat loss, and
allows for the high-salinity water to get up to 90 °C while maintaining
30 °C low-salinity water (SCZ)
• This hot, salty water can then be pumped away for use in electricity
generation, through a turbine or as a source of thermal energy.

14. Membrane ponds::
• The membrane pond inhibits convection by
physically separating the layers with thin
transparent membranes. As with salt
gradient ponds, heat is removed from the
bottom layer

15. Convective solar ponds
• convective solar pond is the shallow solar pond.This pond
consists of pure water enclosed in a large bag that allows
convection but hinders evaporation. The bag has a blackened
bottom, has foam insulation below and two types of glazing
(sheets of plastic or glass) on top.The sun heats the water in the
bag during the day. At night the hot water is pumped into a
large heat storage tank to minimize heat loss.
• Excessive heat loss when pumping the hot water to the storage
tank has limited the development of shallow solar ponds.

16. EXAMPLES ::
 BHUJ SOLAR POND
 El PASO SOLAR POND
 PYRAMID HILL SOLAR POND

17. BHUJ SOLAR POND
• The 6000-square-metre solar pond in Bhuj, the first large-scale pond in
industrial environment to cater to actual user demand.
• It was the first experiment in India, which successfully demonstrated the use of
a solar pond to supply heat to an actual industrial user.
• The Bhuj solar pond was conceived as a research and development project of
TERI, which took over nine years to establish, to demonstrate the feasibility of
using a salt gradient pond for industrial heating
• It supplied totally about 15 million litres of hot water to the dairy at an average
temperature of 75°C between September 1993 and April 1995
• The solar pond is 100 m long and 60 m wide and has a depth of 3.5 m. The pond
was then filled with water and 4000 tonnes of common salt was dissolved in it
to make dense brine
• The Bhuj solar pond constructed by the Tata Energy Research Institute
(TERI).But sadly, today lies in disuse due to lack of financial support by the
government .

18. BHUJ SOLAR POND

19. El PASO SOLAR POND ::
•The El Paso Solar Pond project is a demonstration
project initiated by the University of Texas at El Paso in
1983
•Over 90 graduate and undergraduate students have
been involved in the project, performing tasks ranging
from construction to applied research.
•It has operated since May 1986 and has successfully
shown that process heat, electricity, and fresh water can
be produced in the southwestern United States using
solar pond technology

20. El PASO SOLAR POND

21. PYRAMID HILL SOLAR POND::
• A consortium of RMIT University, Geo-Eng Australia Pty Ltd and Pyramid
Salt Pty Ltd has completed a project using a 3000 square metre solar
pond located at the Pyramid Hill salt works in northern Victoria to
capture and store solar energy using pond water which can reach up to
80°C
• It is planned in a subsequent stage of the project to generate electricity
using the heat stored in the solar pond, thus making this local industry
more energy self-sufficient.
• At the local level this will be a significant boost in an area with high
unemployment and a depressed economy

22. The Pyramid Hill Solar Pond

23. ADVANTAGES::
• Environment friendly energy – no pollution!
• Low maintenance costs.
• Reliable energy source
• Can be constructed according to
requirements.

24. DISADVANTAGES::
• Require a specific location that is not readily
available in all areas.
• Low efficiency
• The Accumulating salt crystals has to be
removed frequently

25. APPLICATIONS ::
 Salt production (for enhanced evaporation or purification of
salt, that is production of ‘vacuum quality’ salt)
 Aquaculture, using saline or fresh water (to grow, for
example, fish or brine shrimp)
 Dairy industry (for example, to preheat feed water to boilers)
 Fruits and vegetables canning industry
 Fruit and vegetable drying
 Grain industry (for grain drying)
 Water supply (for desalination) .

26. CONCLUSION ::
• I conclude that since solar pond technology is the
cheapest and environment friendly process , therefore
solar ponds can be effectively used as replacements in
industries that use fossil fuel to generate thermal energy.
Even though efficiency of this technology is not so good
but we can achieve it by making developments in the
process. I think it will be the future energy source.

27. REFERENCES::
• Fundamental of renewable energy systems by D.MUKHERJEE
• Solar pond technology research journal by K.Goutham, C.Siva krishna
• https://www.britannica.com/technology/solar-pond
• www.eren.doe.gov/consumerinfo/refbriefs/aa8.html (USA dept. of energy )
• https://en.wikipedia.org/wiki/Solar_pond
• http://www.authorstream.com