Accepted Papers - 3.pdf - UNESCO

Figure 5. Cross-section of partitioned
salt-stabilized solar pond
4.2.3 Viscosity Stabilized Pond
This type of pond is based on a similar concept
to that of the partitioned salt-stabilized pond except
that in this case of non-convecting layer contains
thickeners for stabilization rather than a salt gradient.
Polymers and detergents, oil, water gels are
considered to be the required thickeners. The main
advantages of these type of solar ponds are; separate
storage and bottom insulation is not required, it has
reduces diffusion effect and in pond heat exchanger
is practical and energy extraction is simpler.
Figure 6. Cross sectional view of golled solar pond
5. Applications of Solar Pond
5.1 Electricity Generation
A solar pond can effectively be used to generate
electricity by driving a thermo electric device or an
organic Rankine Cycle engine – a turbine powered
by evaporating an organic fluid with a low boiling
point. The concept of solar pond for power
production holds great promise in those areas where
there is sufficient incident solar radiation and terrain
and soil conditions allow for construction and
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operation of large area solar pond necessary to
generate meaningful quantities of electrical energy.
Even low temperatures heat that is obtained from
solar pond can be converted into electrical power.
5.1 Space Heating
In space heating, salt gradient pond proves to
be cheaper than the conventional collector and
storage system. A pond can carry the entire heat load,
without depending upon supplementary sources. It
is very useful in crop drying; where a large quantity
of heat is required for a short period; and heating
from buildings. Unusually low temperature heat is
required for many of these applications, thus it is
necessary to ensure simple and reliable operation
of the pond by identifying problems and finding the
practical solutions.
5.2 Green House Solar Pond Heating System
In this process heat is taken from the bottom
of solar pond by circulating pond brine through
plastic pipe to the shell and tube heat exchanger.
Brine piping is preferred to an in-pond heat
exchanger, as large in-pond heat exchanger surfaces
would be necessary at low pond temperatures. The
heating system is so designed that when the pond is
between 40 o C to 80 o C, fresh water in the tube of the
shell and tube heat exchanger is circulated to a waterto-air
discharge heat exchanger in the greenhouse.
When the pond is between 5 o C to 40 o C; fresh water
from the tubes of the shell and the tube heat
exchanger is pumped through the evaporator of a
heat pump to keep the temperature of the water,
being delivered to greenhouse, slightly above 40 o C.
In addition to above applications, a nonconvective
solar pond can also be used for salt and
mineral production, solar absorption refrigeration,
Rankine cycle solar engines, heating an outdoor
swimming pools, drying of agricultural products and
produces, hot water production for industries,
distillation, industrial process heat, biomass
conversion, food processing etc.
5.3 Solar Pond at Bhuj (INDIA)
The Bhuj Solar Pond was a research,
development, and demonstration project. The
construction of the 6000 m 2 pond started in 1987 at
Kutch Dairy, Bhuj as a collaborative effort between
Gujarat Energy Development Agency, Gujarat Dairy