47 ISSN 0003-701X, Applied Solar Energy, 2020, Vol. 56, No. 1, pp. 47–53. © Allerton Press, Inc., 2020. Russian Text © The Author(s), 2020, published in Geliotekhnika, 2020, No. 1, pp. 67–75. Temperature Mode Optimization for Solar Reverse-Osmosis Water Desalination J. S. Akhatov a, *, Chun Chang b , and T. D. Juraev c a Physicotechnical Institute of SPA “Physics–Sun,” Uzbekistan Academy of Sciences, Tashkent, 100084 Uzbekistan b Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, 100190 China c Bukhara Branch of the Tashkent Institute of Irrigation and Agricultural Mechanization Engineers, Bukhara, 200125 Uzbekistan *e-mail: jahatov@uzsci.net Received July 23, 2019; revised September 11, 2019; accepted October 4, 2019 Abstract—This work is aimed at studying an effect of the temperature of source saline water on the efficiency of reverse osmosis membrane, the service life thereof, as well as the productivity of the considered small-scale solar water-desalination plant. For the case of this plant, alongside with solar photovoltaic cells used to supply necessary electrical energy, solar thermal converters are also recommended to use for a significant reduction in power consumption and for enhancing plant productivity. Keywords: solar radiation, solar photovoltaic cell, thermal conversion, desalination, saline water, reverse osmosis, drinking water supply DOI: 10.3103/S0003701X20010028 INTRODUCTION The global installed capacity of desalination plants as of 2016 has been 79.2 × 10 6 m 3 /day. At the same time, the share of desalination plants operating owing to renewable energy sources (RES) is estimated to amount to 1.0%, as noted in [1, 2]. Currently, in many countries of the world, research is underway to find the most efficient combinations of desalination and RES technologies. However, the choosing of the most suitable desalination technology using renewable energy sources depends on several factors, such as the capacity of the desalination plant, the salinity level of the source water, the abundance of RES resources, the technical infrastructure for their use, etc. The authors of [3] have also presented possible combinations for using renewable energy sources in desalination sys- tems, that could be promising taking into account the aforementioned factors. The analysis of the literature shows that there are numerous publications concerning the use of various types of solar photovoltaic converters connected to reverse osmosis systems ranging from a small produc- tion volume to the desalination on an industrial scale. The authors of [4–12] have presented the results of studies concerning the development and making of desalination plants based on the reverse osmosis tech- nique using different types of RESs and combinations thereof. The existing systems, their design, the condi- tions of use, operating modes, etc., have been ana- lyzed in detail, classified and presented in our papers [13–18]. In addition, taking into account the charac- teristics of the existing systems and climatic conditions of Uzbekistan, as well as the quality of the source saline water and the needs of rural consumers, some designs of low-power solar water desalination plants have been developed and recommended, as presented in [13]. Taking into account worldwide experience, as well as the calculated and experimental results presented in our previous papers [13–18], it can be concluded that one of the promising solutions of this problem consists in developing a desalination plant based on a reverse osmosis system with the use of solar energy. This work is aimed at the studies on the effect of the source saline water temperature on the operation efficiency of such a plant. MATERIALS AND METHODS Based on a thorough analysis, as well as taking into account the climatic conditions and consumer’s requirements in the remote regions of Uzbekistan, we have presented in our previous works [13, 15] a sche- matic diagram of a reverse osmosis desalination plant with a photoelectric converter (Fig. 1). Based on this scheme, a prototype of the plant has been developed and made, and corresponding tests have been carried out, the results of which are pre- sented in [13, 15, 16]. However, in this paper the main attention is paid to a reverse osmosis membrane of the DESALINATION