Solar Desalination for Isolated Areas Technique


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Solar multi-effect humidification desalination plants are the best way to produce environmental friendly potable water in isolated reagions. In this presentation, RGA addresses the design and construction of a Solar MEH desalination prototype at Universidad Simon Bolivar of Caracas-Venezuela

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Solar Desalination for Isolated Areas Technique

  1. 1. Low Cost Solar Desalination Prototype Development for Isolated Communities Eng. Raul Gonzalez-Acuna, M.S. RGA INGENIERÍA Y PROYECTOS, C.A. RIF: J-31097757-7 Improving your Future!
  2. 2. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 2 Contenido Addressing Future Water Shortage1 2 3 MEH Solar Desalination 4 Construction Challenges 5 Desalination plant Technical Information Desalination Technologies
  3. 3. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 3 Million of people Affected by water shortage(a) in 2050 Arnell, 2004 Alcamo et al., 2007 Population Baseline (1995) 1,368 1,601 2050: A2 emission scenario 5,050 (4,351 to 5,747) 6,676 (6,432 to 6,920) 2050: B2 emission scenario 3,362 (2,766 to 3,958) 5,037 (4,909 to 5,166) (a) For this case it is defined as per capita water resources of less than 1000 m3/year Source: L.. J. Mata, Presentación del día del ambiente, USB, 5 de junio 2008 Number of People Affected by 2050 Water Shortage Addressing Future Water Shortage
  4. 4. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 4 Addressing Future Water Shortage Global Warming The World This scenario is impelling major investigation projects in the desalination area, especially in those destined to satisfy isolated areas’ needs. Upcoming Water Shortage Increasing number of Conventional desalination plants Environmental Impact Increasing vulnerability of entire Countries, specially Isolated Communities
  5. 5. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 5 Addressing Future Water Shortage Source: GoogleEarth Venezuela’s Water Resource Reality Venezuela, in spite of being located in the Amazonian region, it has serious water problems, especially in coastal and insular areas where distribution is problematic due to the lack of this resource. In these areas, solar irradiance is very high and relatively constant throughout the year, so it can be used to provide fresh water and energy.
  6. 6. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 6 State Population Anzoátegui 796,519 Aragua 33,094 Carabobo 166,467 Delta Amacuro 58,070 Falcón 761,246 Miranda 107,335 Monagas 15,722 Nueva Esparta 456,454 Sucre 805,001 Trujillo 16,123 Vargas 296,461 Yaracuy 11,223 Zulia 3,128,184 Total 6,651,899 2010 Resident Population in Venezuela’s Coastline Source: Self made INE’s projection 2010 Addressing Future Water Shortage
  7. 7. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 7 Desalination Technologies Salt water desalination is an energy intensive consumption process, normally fossil fuel driven. Reverse Osmosis and Multi-Flash Evaporation are among the most common principles used. For isolated demands, a principle with fewer technical requirements called Multi-Effect Humidification (MEH) can be employed. Hybrid energy proposal for a RO desalination plant
  8. 8. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 8 Parameter Reverse Osmosis Solar MEH Desalination Distilled product for the same size of the installation High production Low production Energy Consumption High energy consumption needed to exceed the sea water osmotic pressure. Primary energy requirements can be reduced by placing a turbine in the output of the rejected water Low. The fluid displacements can be forced in the air and water cycles by thermosyphon and hydrostatic pressure respectively Training manpower for operation and maintenance It requires a qualified personnel to operate the complex control systems that the installation has; and who can perform regular maintenance of the high pressure pump and semi-permeable membranes It does not require skilled labor as the system requires almost no moving parts and maintenance simply consist on cleaning Flexibility in operation Low. Membranes working out of the normal operating range decrease its life rapidly High Brine Disposal It must have a system for disposal of brine in which it is diluted to pour it into the sea The brine practically don’t change its concentration Specialization of Components High Low. The components can be made with commercial materials (copper, aluminum, etc.) Desalination Technologies
  9. 9. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 9 Research branch initiated to solve the water problems of isolated populations, starting with the fishermen communities that work near Dos Mosquises cay in Los Roques National Park, a set of cays located in the Caribbean Sea at 86 miles from Vargas State’s coast. Dos Mosquises cay. Source: R. Gonzalez-Acuna MEH Solar Desalination
  10. 10. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 10 • Low initial and maintenance costs. • Easy transportation. • Replicability. • Low energy consumption. • The utilization of as many homemade components as possible. MEH Solar Desalination Main Objective Construction of a prototype that could distill 25 liters (6.6 US gal) of drinking water per day. This prototype was designed considering the following: Design Criteria Sunset at Dos Mosquises Cay. Fuente: R. Gonzalez-Acuna
  11. 11. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 11 MEH Solar Desalination Desalination Research Branch Phases 1 Theoretical Design & Sensitivity Analysis 2 3 Construction & System Performance Testing Water Properties Testing
  12. 12. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 12 MEH Desalination System Configuration Configuration Selection According to the design considerations, and taking into account the applicable process types, the configuration of the prototype was decided to be a single stage, open water – closed air cycle with a flow of air due to natural convection. Schematic of a MEH Unit Source: R. Gonzalez-Acuna Advantage: Using water vapor latent heat of condensation for preheating the salt water in the Condenser and reduce the main energy input required in the Solar Collector
  13. 13. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 13 Most Important Activities 1. Mathematical model development to simulate the plant’s operation and equipment sizing 2. 3D CAD design of the desalination plant, material selection and caliber. Resistance analysis. 3. Procurement and construction of cupper equipment for the condenser and solar collector. 4. Stagnation and hydrostatic resistance tests of the cupper ducts made. 5. Casing construction of the different equipments, air ducts and structural support. 6. On site transportation, and foundation works for the installation of the desalination unit. 7. Design and construction of a testing rig to characterize the built solar collector Fuente: R. Gonzalez-Acuna Construction Challenges
  14. 14. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 14 Most Important Activities (Cont.) 8. Solar collector characterization according with ANSI/ASHRAE 93-2003 Standard requirements. Determination of its maximum exergetic gain operation criteria, and establish start and stop criteria. Master in Science thesis awarded with the Honorable Mention of the ASME’s Solar Energy Division Graduate Student Award. 9. Design and construction of a testing rig to characterize the desalination plant 10. Assembly and commissioning of the desalination plant. 11. Desalination plant start-up, preliminary test and development of performance indicators 8 10 Construction Challenges
  15. 15. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 15 Casing Construction Solar Collector Internal Casing Condenser Internal Casing Humidifier Internal Casing Brine and Distillate Collection System Fuente: R. Gonzalez-Acuna Construction Challenges
  16. 16. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 16 Structural System Construction Desalination Base Solar Collector Base Zinc Chromate Coating Final Alumina Coating Construction Challenges
  17. 17. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 17 Stagnation Tests Construction Challenges
  18. 18. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 18 Solar Collector Coating, Isolation and Assembly High temperature resistent varnish coating Assembly test 1: Absorber – Internal Casing Absorber Pre-Assembly: Black paint Assembly test 2: Absorber, Isolation (High density PE) and casings Construction Challenges
  19. 19. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 19 Solar Collector On Site Installation Adjustable Tilt base Installation Final Assembly: Transparent cover Installation On site final installation and stagnation tests Construction Challenges
  20. 20. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 20 Characterization of the Solar Collector and Determination of the Exergetic Operation Point Solar Collector Testing Rig Desalination plant operation point (m) using USB environmental data Construction Challenges
  21. 21. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 21 On site Assembly and Construction of the the Desalination plant Testing Rig for Performance Analysis Left: Structure Installation. Center: Humidifier packing material. Right: Desalination plant final Assembly. Source: R. Gonzalez-Acuna Construction Challenges
  22. 22. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 22 Final Product: Left: Assembly test at Simon Bolivar University E Lab. Center: Desalination Plant Render. Right: Desalination Plant Commisioning. Source: R. González-Acuna Construction Challenges
  23. 23. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 23 Desalination Plant Tech Details Technical Information Tests Information Financial Information Cycle Type Single Stage (Open Water – Closed Air) Test performed/ N° of tests Production Capacity/ 2 Labor Hours Invested 9,500 Rated Capacity; Operation time per day 25 L/day; 11.5 h Average production reported 0.7 L/h Project Duration 2007-2012 Condenser, Solar Collector Type/ Material Sandwich type/ Cupper Test period/month year 9 am – 4 pm / October 2012 Average inflation rate 30% Plant’s dimensions Length: 1.1 m; wide: 1.5 m; height: 2.,3 m Test Place Sartenejas Valley Simón Bolívar University (USB), Caracas, Vzla. Monetary resources invested (equipment, labor, etc) Bs. 45,000.00 ($6,428.57) average exchange rate of 7 Bs/$ Solar collector area Apert.: 1.68 m2; Capt.: 1.25 m2 Stopping cause Condenser ducts’ failure. Lack of resources to repair them -- -- The SC aperture area was enough to produce de required fluid output temperature Steady State test Not performed -- --
  24. 24. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 24 Most Relevant Awards
  25. 25. Raul Gonzalez-Acuna. RIF: J-31097757-7 Page 25 Thank you for your attention, Questions? @RGA_IP