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Solar Distillation and its applications in the Agriculture sector - Monica Boodhan_0

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Solar Distillation and its applications in the Agriculture sector - Monica Boodhan_0 Powered By Docstoc
					   RENEWABLE ENERGY OPTIONS
  FOR THE AGRICULTURE SECTOR
WITH A FOCUS ON WOMEN FARMERS




  Amaryllis Beach Resort - Barbados
          27th – 29th August 2012
   SOLAR DISTILLATION AND ITS
APPLICATIONS IN THE AGRICULTURE
             SECTOR

          Monica K. Boodhan
             Department of Physics
        The University of the West Indies
             St. Augustine Campus
                   INTRODUCTION
• The most basic necessity of human existence on earth is
  an abundant supply of potable water
• Studies have shown that human existence and settlement
  across the globe are dependent on the availability of an
  abundant supply of potable water.
• An estimated 80% of the earth is covered by water:
     97.5% saline
     2.5 % in underground reserves and frozen as ice
     < 0.25 % available as fresh water

                          Monica K. Boodhan
                     INTRODUCTION
• World Health Organisation (WHO) reports estimate:
     3900 children die daily due to water-borne diseases (2010).
     One child dies or goes blind per minute due to consumption of
     contaminated water (2010).
     Approximately 13% of the world’s population (0.88 billion people)
     lack access to potable water (2010).
     88% of the 4 billion annual cases of diarrhoea are linked to the lack
     of potable water (2007).
     Annually, 1.8 million people die from de-hydration due to diarrhoea
     (2007).
     An estimated 94% of annual diarrhoea cases are preventable
     through environmental modifications (2007).

                             Monica K. Boodhan
                    SOLAR DISTILLATION
• Solar distillation is a process that employs the use of Solar radiation to
  purify brackish, saline and polluted water.
• The process of Solar distillation is analogous to the naturally occurring
  hydrologic cycle.




                                 Monica K. Boodhan
            A WALK BACK IN HISTORY
• 4th century B.C. as evidenced by several written pieces of
  Aristotle.
• 1742, Nicolo Ghezzi of Italy – first documented evidence.
• 1872, Charles Wilson of Las Salinas, Chile - built the first
  known large-scale solar distillation plant with daily capacity
  of 20,000 l.
• 1950’s - research of large-scale solar distillation units.
• 1957 to1980 – at least 40 units were built across the world and
  tested.
• Minimal research in this field until the 1990’s.

                          Monica K. Boodhan
 THE DISTILLATION PROCESS

                  Feed water




Collection                         Solar radiation
                                     absorbed




Condensation                         Heating




                  Evaporation




               Monica K. Boodhan
              WHY SOLAR DISTILLATION
• Other processes include:
      Reverse Osmosis (RO).
      Humidification-Dehumidification (HDH).
      Multi Stage Flash (MSF).
      Multiple Effect Desalination (MED).
• Solar distillation:
      Produces clean water for consumption.
      Environmentally friendly.
      Stills are very easy to construct and simple to operate.
      Units are low maintenance.
      Affordable.


                                 Monica K. Boodhan
                    ADVANTAGES
• Solar energy is renewable, abundant, has a widespread
  distribution, it is easy to use and it is totally free
• Solar distillation units are easy to construct, simple to
  operate and low maintenance
• Solar distillation produces 99.9% pure water for
  consumption
• These units do not have a carbon footprint as they are
  100% clean and emit absolutely no harmful toxins into the
  atmosphere

                        Monica K. Boodhan
                   DISADVANTAGES
•   Cost
•   Weather dependence
•   Time of day
•   Geographic location
•   Decreased productivity with time
•   Requires some skills and time to maintain



                          Monica K. Boodhan
                     LIMITATIONS
• The system can only be used when there is a supply of
  thermal energy readily available
• The system will not be efficient in countries with little or
  no solar energy available




                          Monica K. Boodhan
         COMPONENTS OF A SOLAR STILL
•   Solar Collector
•   The transparent cover
•   The framing structure
•   Distillate trough and storage
•   Sealants, insulation and connecting devices




                             Monica K. Boodhan
             TYPES OF SOLAR STILLS
• Concentrating Collector Stills




                        Monica K. Boodhan
             TYPES OF SOLAR STILLS
• Multiple-tray tilted (Cascade)




                        Monica K. Boodhan
           TYPES OF SOLAR STILLS
• Basin Type




                  Monica K. Boodhan
            TYPES OF SOLAR STILLS
• Tilted Wick




                   Monica K. Boodhan
PLASTIC STILLS




   Monica K. Boodhan
             HEAT AND MASS TRANSFER
• Heat is a form of energy that may be transferred from one body to
  another if a temperature difference exists. In solar distillation the
  heat transfer is due to both internal and external losses.




                             Monica K. Boodhan
              THERMAL RADIATION
• This involves the transfer of heat from a region of higher
  temperature to a region of lower temperature via
  electromagnetic waves.
• For thermal radiation, the electromagnetic radiation is of
  the form of infrared radiation. This infrared radiation is
  incident from the sun.




                         Monica K. Boodhan
            THERMAL CONDUCTION
• Conduction is the transfer of thermal energy between
  particles within a system.
• For conduction, the particles must be in direct contact
  with one another.
• A temperature gradient must exist.
• The rate at which energy is transferred is dependent on
  parameters of the system which include its geometry,
  thickness and the material from which it is made.

                        Monica K. Boodhan
               THERMAL CONVECTION
• Convection is heat transfer that occurs within a fluid.
• Heat is transferred from one part of the fluid of higher temperature to
  another part of the fluid at a lower temperature.
• Convection can be both free and forced.
• Free convection occurs when there is a difference in temperature
  between the fluid and the contact surface causing a variation in
  density of the fluid and thus buoyancy occurs. It is not confined
  within a space by solid boundaries.
• Forced convection occurs when an externally applied pressure
  difference produce forces which cause motion within the fluid.
• Thermal conduction may be both forced and free simultaneously.


                              Monica K. Boodhan
 APPLICATIONS IN THE AGRICULTURE SECTOR
• Approximately 70% of the water used worldwide is utilised in agricultural
  application such as irrigation.




                                Monica K. Boodhan
APPLICATIONS IN THE AGRICULTURE SECTOR
• Purified water is essential to irrigation to enable greater yield and
  quantity of crops, maintenance of soil productivity, and protection
  of the environment.




                             Monica K. Boodhan
APPLICATIONS IN THE AGRICULTURE SECTOR

• Livestock require clean water for consumption purposes.




                        Monica K. Boodhan
APPLICATIONS IN THE AGRICULTURE SECTOR
• Extraction of pure and refined oils by evaporation of the volatile
  essence of the plant material for cosmetic, aroma therapeutic and
  medicinal uses.




                            Monica K. Boodhan
      HOW TO EXTRACT OIL FROM PLANTS
•   Instructions
     – Harvest plant material right before beginning the distillation process, to ensure it is at its freshest.
          Plants that sit after harvesting and before extracting essential oils can become desiccated and some
          of the essential oils can evaporate.
     – Fill the still approximately half full with plain water.
     – Place plant materials in the "steam" basket of the still. The steam basket sits above the liquid,
          similar to a kitchen steamer for vegetables. Fill the steamer with the plant materials but do not pack
          them in tightly.
     – Place a receptacle under the outlet valve of the still to catch and hold the resulting liquid, which is
          a mixture of water and distilled plant oil. The oil will rise to the top and you can skim it off and
          separate it from the distilling water.
     – Put the still together, following the directions and procedures relative to your particular model.
     – Turn on the heat source. Allow the still to extract the oil from the plant materials.
•   Read more: How to Extract Oil From Plants | eHow.com http://www.ehow.com/how_4461209_extract-
    oil-from-plants.html#ixzz24qsuEBar


                                             Monica K. Boodhan
                     CONCLUSION
• Solar distillation is a definite solution to the global water
  crisis
• Research is being conducted to increase the efficiency of
  the present designs of the cascade-design and basin-type
  solar stills




                          Monica K. Boodhan

				
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