Effect of Leakage Modification and Cooling Flow Rate Increase of Water-Cooled Condenser on NVD System Performance Equipped with Vacuum Tube Collectors

Subject Areas : Renewable Energy

Mohammad Javad  Abbaspour ¹ (M.Sc., Renewable Energy Engineering, Faculty of Natural Resources and Environment, Islamic Azad University, Science and Research Branch, Tehran, Tehran Iran)
mohammad behshad  Shafiei ² (Professor, Faculty of Mechanics, Sharif University of Technology, Tehran, Iran *(Corresponding Author()

Received: 2019-02-04 Accepted : 2019-05-14 Published : 2020-10-22

Keywords: Solar Desalination, Evacuated Tube Collector, Natural Vacuum Distillation,

Abstract :

Background and Objective: Lack of access to sufficient fresh water is a major threat to people around the world, and to prevent this, extensive research is being done to find new ways to purify different sources of brackish water at lower cost, energy and environmental impacts. The purpose of this study is to produce the freshwater through an NVD system using vacuum tube collectors and vacuum creation by a vacuum pump. Hence, this kind of system could be considered as an innovative combination one; in addition, the effect of different vacuum pressures on yield, then the effect of leakage modification and flow rate increase of cooling water on the system performance were experimentally investigated. Method: In this research, a vacuum pump was utilized to create an initial vacuum, and when it is switched off, a barometric water column maintains the vacuum naturally throughout the consecutive days. The vacuum collectors were used in order to enhance the saline water heat transfer; later the system performance was continually examined. After the improvements were carried to the system, the yield and efficiency were analyzed and compared with the first test. Furthermore, a pressure gauge, a pyranometer and some thermocouples were applied so as to measure the system pressure, solar radiation and temperatures respectively. Findings: The current study found that the yield and efficiency of the system increased by raising the vacuum pressure; besides, after the leakage modification and cooling water flow rate enhancement, the efficiency has been insignificantly varied in the first consecutive days resulting in a superior capability to produce fresh water for more than three days without reusing the vacuum pump. Discussion and Conclusion: The results of this study indicated that raising the vacuum pressure increased the yield and efficiency so that they reached to 8.114 kg/m2d and more than 51% respectively. Moreover, the efficiency slightly varied and as a result, the system would be able to produce freshwater for more than three days without reutilizing vacuum pump.

References:

1. Water for a sustainable world, 2015.The United Nations World Water Development Report


2. Shatat, M., Worall, M., Riffat, S., 2013.Opportunities for solar water  desalination worldwide: Review. Sustainable Cities and Society Journal, Vol. 9 ,pp. 67-80


3. Gorjian, S., Ghobadian, B., 2015.Solar desalination: A sustainable solution to water crisis in Iran. Renewable and Sustainable Energy Reviews, Vol 48 ,pp. 571-584


4. Li, Chennan., Goswami, Y., Stefanakos, E., 2013.Solar assisted sea water desalination: A review. Renewable and Sustainable Energy Reviews Journal, Vol. 19, pp. 136–163


5. Kalogirou, A., 2009.Solar Energy Engineering: Processes and Systems. Elsevier Academic Press.


6. Morad, M., El-Maghawry, H., Wasfy, K., 2017.A developed solar-powered desalination system for enhancing fresh water productivity. Sol. Energy Journal, Vol. 146, pp. 20–29


7. Bilgil, A., Hırlakoğlu, B., 2017.An experimental study on desalination at vacuum environment under low pressure and low condensation temperatures. Desalination Journal, Vol 411,pp. 9-18


8. Bemporad, G., 1995.Basic hydrodynamic aspects of a solar energy based desalination process. Solar Energy Journal, Vol. 54 ,pp. 125–134


9. Midilli, A., Ayhan, T., 2004. Natural vacuum distillation technique—part I: theory and basics.International Journal of Energy Research, Vol. 28, no. 4, pp. 355–371


10. Midilli, A., Ayhan, T. , 2004.Natural vacuum distillation technique—part II: theory and basics.International Journal of Energy Research, Vol. 28, no. 5, pp. 373–389


11. Ambarita, H., 2016.Study on the performance of natural vacuum desalination system using low grade heat source. Case Studies in Thermal Engineering Journal, Vol. 8, pp. 346–358


12. Al-Kharabsheh, S., Goswami, D., 2004.Theoretical analysis of a water desalination system using low grade solar heat. Solar Energy Journal. Vol. 126, no. 2, pp. 774–780


13. Choi, S., 2017.Thermal type seawater desalination with barometric vacuum and solar energy. Energy Journal, Vol. 141, pp. 1332–1349


14. Shafii,M. B., Shahmohamadi., M, Faegh., H. Sadrhosseini., 2016. Examination of a novel solar still equipped with evacuated tube collectors and thermoelectric modules. Desalination, vol. 382


15. M ,Faegh., Shafii, M. B., 2017. Experimental investigation of a solar still equipped with an external heat storage system using phase change materials and heat pipes. Desalination Journal, vol. 409


16. Gude, V., Nirmalakhandan, N. 2008. Desalination Using Low-Grade Heat Sources. Energy Engineering Journal, Vol. 134, pp. 95-101.


17. Eames, I.W., Maidment, G., Lalzad, A., 2007.A theoretical and experimental investigation of a small-scale solar-powered barometric desalination system. Applied Thermal Engineering.Journal. Vol. 27, pp. 1951–1959


18. Gude, V. G., Nirmalakhandan, N., Deng, S., Maganti, A., 2012.Low temperature desalination using solar collectors augmented by thermal energy storage. Applied Energy Journal, Vol. 91, pp. 466-467


19. Hosseini, A., Banakar, A., Gorjian, S. 2017. Development and performance evaluation of an active solar distillation system integrated with a vacuum-type heat exchanger. Desalination Journal, Vol 435, pp. 45-59


20. Hamawand, I., Lewis, L., Ghaffour, N., Bundschuh, J., 2017.Desalination of salty water using vacuum spray dryer driven by solar energy. Desalination Journal, Vol. 404, pp. 182-191


21. H. E. S. Fath, M. El-Samanoudy, K. Fahmy., A. Hassabou. 2003. Thermal-economic analysis and comparison between pyramid-shaped and single-slope solar still configurations. Desalination Journal, 159, pp. 69–79.