SOLAR POND TECHNOLOGY

1. SOLAR POND TECHNOLOGY SHWETA SINGH CHEMICAL ( V SEM) 1

2. SOLAR ENERGY 1 . Solar energy is an abundant and r renewable energy source. 2 .The use of solar energy in india has been very limited. This is because it is dilute energy source. 3 .Energy must be collected over large area. 4 .One way to overcome this problem is to trap solar energy through the use of SOLAR POND. 2

3. WHAT A SOLAR POND IS A solar pond is a body of water that collects and stores solar energy. Water warmed by the sun expands and rises as it becomes less dense. Colder water moves down creating a natural convective circulation that mixes the water and dissipates heat. Its design reduces convection in order to store heat collected by pond. 3

4. Salinity gradient prevents convection current. Solar radiation reaches the lower layer which contains conc. salt solution. Temperature in this layer rises but heat is unable to move to surface by convection. Solar heat is thus stored in the lower layer of the pond. 4

5. SOLAR POND 5

6. WORKING PRINCIPLE Sun’s rays heat the water and heated water reaches the top and loses heat in the atmosphere. Pond water remains at atmospheric temperature. Solar pond restrict this tendency by dissolving salt in bottom layer making it too heavy to rise. 6

7. MAIN FUNCTIONS OF SOLAR POND Collection of radiant energy and its conversion into heat. Storage of heat. Transport of thermal energy out of the system 7

8. IN MAN MADE SOLAR POND The bottom of the pond is lined with durable plastic liner such as black polythene. Dark surface at the bottom increases the absorption of solar radiation. Salts like sodium chloride and magnesium chloride dissolved in bottom for making it denser. 8

9. SOLAR POND CONSISTS OF 3 ZONES An upper convective zone of clear fresh water that acts as solar receiver. A gradient which serves as the non-convective zone. Lower convective zone with the densest salt concentration serving as the heat storage zone 9

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11. APPLICATION Salt production Aquaculture,using saline or fresh water Dairy industry(to preheat feed water to boilers) Fruits and vegetable canning industry Grain industry(for grain drying) Water supply(for desalination) 11

12. PROCESS HEAT Scope for process heat applications( i.e water heated to 80 to 90 degree celcius ),when a large quantity of hot water is required such as textile processing and dairy industries. 12

13. DESALINATION Solar ponds can provide a cost effective solution to the portable drinking water problems, desalination cost work out to be 7.5 paisa per litre , in coastal villages 13

14. REFRIGERATION Life saving drugs like vaccines can be preserved for long time in cold storage using solar pond technology in conjunction with ammonia based absorption refrigeration system. 14

15. BHUJ SOLAR POND 15

16. ADVANTAGES Low investment cost per installed collection area. Thermal storage is incorporated into the collector and is of very low cost. Can operate in almost any climate. Can store solar heat much more efficiently than a body of water of same size. 16

17. DISADVANTAGES Require a specific location that is not readily available in all areas. Excessive wind can blow water away or evaporate the top layer of water at high rate. Risk of contamination of ground with high salt levels from water in pond. 17

18. CONCLUSION Solar ponds can be effectively used as replacements in industries that use fossil fuels to generate energy. Solar ponds can be used for process heating, refrigeration, water desalination etc. It will be the future energy source. 18

19. THANK YOU 19