Solar pond technology, Zones of solar pond, Solar energy,Advantages,limitations,applications, Phase change materials

1. Jaison Prem D' Souza

2.  Solar energy is an abundant and renewable energy source.
 The use of solar energy in india has been very limited.This
is because it is dilute energy source
 Energy must be collected over large area.
 One way to overcome this problem is to trap solar energy
through the use of SOLAR POND.
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3. • A solar pond is a body of water that collects
and stores solar energy.
• Water is 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.
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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.
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7. • 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.
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8. • Collection of radiant energy and its conversion into heat.
• Storage of heat.
• Transport of thermal energy out of the system.
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9. • 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.
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10. • 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)
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11. • Low investment cost per installed collection area.
• Thermal storage is incorported into the collector and is of
very low cost.
• Can operate in almost any climate
• can store solar heat much more efficiently that a body of
water of same size.
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12. • 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.
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13. • Solar ponds can be effectively used as replacements in
industries that use fossil fuel to generate energy.
• Solar ponds can be used for process
heating,refrigeration,water desalination etc. It will be the
future energy source.
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14. Phase Change Materials
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15. A phase-change material is a substance presenting a
high heat of fusion,and capable of storing and releasing
large amounts of energy.Heat energy is absorbed or
released when the material changes from solid to liquid
phase and vice versa, thus being classified as latent heat
storage units.
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17. • A PCM absorbs and releases thermal energy in order to
maintain a regulated tempertaure.
• When a PCM is in its solid phase it will absorb heat as the
external temperature rises.
• The temperature of the PCM will mirror the external
temperature until the PCM's melt point reached.
• When the external temperature reaches the melt point of
the PCM, the PCM will begin to melt, i.e “phase change”
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18. • During the phase change process the PCM will absorb
large amount of heat with almost no change in
temperature .
• During this time period,the PCM is providing a cooling
effect.
• The amount of time the PCM will provide a cooling effect
is determined by the PCM's enthalpy of melting,also
called the latent heat of fusion of melting.
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19. • Substantial energy savings when used in the construction
of buildings and structures.
• Small electronic devices,such as laptops and smart
phones,can be cooled where space for active cooling
systems such as fans is not available.
• Cooling and heating relief in remote locations without
access to electricity.
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20. Applications
• Packaging
• Building and construction
• Bedding
• Electronics
 Medicines
 Food items
 Biologcal samples
 Roofing
 Wall coverings
 Mattress
 Computers
 Smart phones
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