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Specific energy consumption of PV reverse osmosis systems. Experiment and theory
Author(s) -
Fraidenraich N.,
Vilela O. C.,
Lima G. A.
Publication year - 2013
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.1239
Subject(s) - limiting , reverse osmosis , desalination , range (aeronautics) , environmental science , energy consumption , generator (circuit theory) , photovoltaic system , variable (mathematics) , process engineering , control theory (sociology) , engineering , computer science , mathematics , electrical engineering , mechanical engineering , physics , thermodynamics , chemistry , power (physics) , membrane , mathematical analysis , biochemistry , control (management) , artificial intelligence , aerospace engineering
Reverse osmosis equipment (RO), driven by photovoltaic systems, can be a reliable way to provide drinking water for the population of remote areas. The specific energy consumption (SEC) of an RO equipment is an important parameter to evaluate the equipment quality and its operating conditions. In this paper, we describe a theoretical study of the SEC of an RO equipment. It is briefly analyzed the SEC for ideal systems. Then, we obtain analytic expressions for real systems, operating under variable conditions. Finally, a limiting case, when the applied pressure is equal to the transmembrane pressure at the output of the equipment, is analyzed. An experimental study of a PV‐RO equipment conducted on a commercial multistage desalination unit over a broad range of operating conditions is described. A variable speed drive couples the PV generator to the RO system. Experimental results obtained for the system present a minimum (SEC) lying in a range of (R) between 0.2 and 0.4, smaller than the value obtained for the limiting case (approximately 0.5). The minimum values obtained for hydraulic (SEC) are around 0.32 kWh m ‐3 for 2,000 mg L ‐1 and 0.65 kWh m ‐3 for 5,000 mg·L ‐1 . For the limiting case the minimum hydraulic SEC are 0.18 kWh m ‐3 and 0.47 kWh m ‐3 , respectively (R = 0.5). A good agreement is found between predicted and measured results. The proposed procedure for calculating (SEC) is simple, precise and general, yielding a valuable tool to evaluate whether the region of operation of a PV‐RO system is adequate, according to the main aim of reducing water costs. Copyright © 2012 John Wiley & Sons, Ltd.