The article is devoted to the improvement of the design of a desalination solar plant for more efficient and economical production of desalinated water due to intensive evaporation of the boiling solution, reduction of energy losses to the external environment and the absence of the need for continuous adjustment of the direction of the light-receiving part of the solar plant. The expedient parameters of the angles of inclination of the optical axis of the lens relative to the azimuth and the incidence vector of solar radiation, which ensure high performance of the solar plant, were experimentally substantiated. The use of a solar collector equipped with an additional heat accumulator will allow water to be supplied for desalination at a temperature of more than 50 °C in sunny weather, and at a temperature of 33–36 °C in variable cloudiness, which will help to increase the efficiency of the desalination solar plant. The presence of a heat accumulator and a layer of thermal insulation under cloudy conditions allows maintaining the operating water temperature at 33–36 °C 4.4 times longer than without them.