In order to reasonably use solar energy to solve problems such as land desertification and soil salinization in Southern Xinjiang, this paper proposes a system combining photothermal and flash evaporation technologies, which use local saline water for desalination treatment to achieve secondary utilization of water resources. Firstly, we introduce the whole system of the photovoltaic desalination plant. As an important heat-collecting element of the system, the solar tube is the key to whether this plant can work efficiently. Then, we carry out the detection and theoretical derivation of data along the tube. We establish a two-phase flow model of saline water in the tube, considering convective heat transfer, and define the formula of the heat collecting efficiency factor. Finally, based on iterative calculation, the temperature trend of the tube and the change law of the two-phase flow are obtained, and the ecological and economic benefits and energy efficiency of the system are analyzed.

Water shortage is one of the main issues affecting agricultural development in many regions, and the problem of crop yield reduction caused by the salinisation of irrigation water has become increasingly prominent. Xinjiang is a major agricultural development province in China, with mostly remote agricultural land and an unstable electricity supply. We have introduced a combination of photovoltaic and reverse osmosis technology in the local Aksu region, using wastewater for irrigation to improve returns. In order to verify the feasibility of two schemes, we evaluated the benefits of the apple orchard after irrigation with desalinated water. The result shows that the net present value of the orchard has become 2.4 times that of the initial. It not only used secondary wastewater resources in the drainage canal, but also changed the trend of apple orchard profits declining year by year. The influence of various factors on the income of the orchard has obviously reduced, and the possibility of investment profit is greatly improved.