International Scientific Journal


Solar energy is major renewable energy resource which can potentially fulfill 100% energy demand of the world while releasing no polluting agents to the atmosphere in contrast to the conventional fossil fuels. However, due to its intermittent nature, solar energy requires effective storage of energy for utilizing during the night and cloudy weather. A solar pond is a promising solution because it has its own energy storage which is suitable for low-temperature application like building heating and cooling. This paper presents a thermal analysis of a salt gradient solar pond while extracting heat from the lower convective zone. A mathematical model of 2m2 surface area is developed. Efficiency analysis is performed numerically using a MATLAB code for steady temperature difference of 30°C as well as 20°C across the gradient layer for three different pond sizes of depths 1,5m, 1,0m and 0.5m. The thermal efficiency of first pond of 1.5m depth varies from around 21% in summer to 11% in winter. Thermal efficiency of solar pond drops significantly by reducing its size and non-convective zone thickness: Annual average efficiencies are 21% 19% and 9.5% for the three ponds of 1,5m, 1,0m and 0.5m depths respectively. So it is recommended to prefer a pond 1.5m of over others. However, the efficiency of smaller the pond can be significantly improved by compromising on quality the of thermal energy, efficiency of 0.5m pond rises to 17% when operating at temperature just 20°C above ambient, compared with 9.5% for 30°C above ambient. Solar pond therefore proves to be suitable for effectively utilizing solar energy and can present an effective solution for low temperature energy needs like space heating.
PAPER REVISED: 2017-05-26
PAPER ACCEPTED: 2017-07-04
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  1. Johansson, T.B., et al., The Potentials of Renewable Energy, in International Conference for Renewable Energies 2004: Bonn.
  2. Goldemberg, J., World Energy Assessment 2000, New York: UNDP.
  3. Ali, M., et al., Performance analysis of a low capacity solar tower water heating system in climate of Pakistan. Energy and Buildings, 2017. 143: p. 84-99.
  4. Ali, H.M., et al., Outdoor Testing of Photovoltaic Modules During Summer in Taxila, Pakistan. Thermal Science, 2016. 20(1): p. 165-173.
  5. Valderrama, C., et al., Solar energy storage by salinity gradient solar pond: Pilot plant construction and gradient control. Desalination, 2011. 279(1-3): p. 445-450.
  6. Akrour, D., M. Tribeche, and D. Kalache, A theoretical and numerical study of thermosolutal convection: stability of a salinity gradient solar pond. Thermal Science, 2011. 15(1): p. 67-80.
  7. Hill, A.A. and M. Carr, Stabilising solar ponds by utilising porous materials. Advances in Water Resources, 2013. 60: p. 1-6.
  8. Wang, H., et al., Experimental and theoretical study on temperature distribution of adding coal cinder to bottom of salt gradient solar pond. Solar Energy, 2014. 110: p. 756-767.
  9. Wang, H., et al., A Laboratory experimental study on effect of porous medium on salt diffusion of salt gradient solar pond. Solar Energy, 2015. 122: p. 630-639.
  10. Leblanc, J., et al., Heat extraction methods from salinity-gradient solar ponds and introduction of a novel system of heat extraction for improved efficiency. Solar Energy, 2011. 85(12): p. 3103-3142.
  11. Date, A., et al., Heat extraction from non-convective and lower convective zones of the solar pond: a transient study. Solar Energy, 2013. 97: p. 517-528.
  12. Karakilcik, M., et al., Performance assessment of a solar pond with and without shading effect. Energy Conversion and Management, 2013. 65: p. 98-107.
  13. Dehghan, A.A., A. Movahedi, and M. Mazidi, Experimental investigation of energy and exergy performance of square and circular solar ponds. Solar Energy, 2013. 97: p. 273-284.
  14. Liu, H., et al., Experiment and simulation study of a trapezoidal salt gradient solar pond. Solar Energy, 2015. 122: p. 1225-1234.
  15. Sogukpinar, H., I. Bozkurt, and M. Karakilcik, Performance Comparison of Aboveground and Underground Solar Ponds. Thermal Science, 2016.
  16. Assari, M.R., H. Basirat Tabrizi, and A. Jafar Gholi Beik, Experimental studies on the effect of using phase change material in salinity-gradient solar pond. Solar Energy, 2015. 122: p. 204-214.
  17. Ziapour, B.M., M. Shokrnia, and M. Naseri, Comparatively study between single-phase and two-phase modes of energy extraction in a salinity-gradient solar pond power plant. Energy, 2016. 111: p. 126-136.
  18. Alcaraz, A., et al., Enhancing the efficiency of solar pond heat extraction by using both lateral and bottom heat exchangers. Solar Energy, 2016. 134: p. 82-94.
  19. Bozkurt, I. and M. Karakilcik, The daily performance of a solar pond integrated with solar collectors. Solar Energy, 2012. 86(5): p. 1611-1620.
  20. El-Sebaii, A.A., et al., History of the solar ponds: A review study. Renewable and Sustainable Energy Reviews, 2011. 15(6): p. 3319-3325.
  21. Ranjan, K.R. and S.C. Kaushik, Thermodynamic and economic feasibility of solar ponds for various thermal applications: A comprehensive review. Renewable and Sustainable Energy Reviews, 2014. 32: p. 123-139.
  22. Singh, B., et al., Small Scale Power Generation using Low Grade Heat from Solar Pond. Procedia Engineering, 2012. 49: p. 50-56.
  23. Date, A. and A. Akbarzadeh, Theoretical study of a new thermodynamic power cycle for thermal water pumping application and its prospects when coupled to a solar pond. Applied Thermal Engineering, 2013. 58(1-2): p. 511-521.
  24. Tundee, S., N. Srihajong, and S. Charmongkolpradit, Electric Power Generation from Solar Pond Using Combination of Thermosyphon and Thermoelectric Modules. Energy Procedia, 2014. 48: p. 453-463.
  25. Kanan, S., J. Dewsbury, and G.F. Lane-Serff, Simulation of Solar Air-Conditioning System with Salinity Gradient Solar Pond. Energy Procedia, 2015. 79: p. 746-751.
  26. Appadurai, M. and V. Velmurugan, Performance analysis of fin type solar still integrated with fin type mini solar pond. Sustainable Energy Technologies and Assessments, 2015. 9: p. 30-36.
  27. Ding, L.C., A. Akbarzadeh, and A. Date, Electric power generation via plate type power generation unit from solar pond using thermoelectric cells. Applied Energy, 2016. 183: p. 61-76.
  28. Ding, L.C., et al., Passive small scale electric power generation using thermoelectric cells in solar pond. Energy, 2016. 117, Part 1: p. 149-165.
  29. Elsarrag, E., et al., Solar pond powered liquid desiccant evaporative cooling. Renewable and Sustainable Energy Reviews, 2016. 58: p. 124-140.
  30. Bernad, F., et al., Salinity gradient solar pond: Validation and simulation model. Solar energy, 2013. 98: p. 366-374.
  31. Giestas, M.C., J.P. Milhazes, and H.L. Pina, Numerical Modeling of Solar Ponds. Energy Procedia, 2014. 57: p. 2416-2425.
  32. Abbassi Monjezi, A. and A.N. Campbell, A comprehensive transient model for the prediction of the temperature distribution in a solar pond under mediterranean conditions. Solar Energy, 2016. 135: p. 297-307.
  33. Sayer, A.H., H. Al-Hussaini, and A.N. Campbell, New theoretical modelling of heat transfer in solar ponds. Solar Energy, 2016. 125: p. 207-218.
  34. Husain, M., et al., Simple methods for estimation of radiation flux in solar ponds. Energy Conversion and Management 2004. 45 p. 303-314.
  35. Karakilcik, M., I. Dincer, and M.A. Rosen, Performance Investigation of a Solar Pond. Applied Thermal Engineering, 2006. 26(7): p. 727-735.

© 2019 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence