Conditions for economical benefits of the use of solar energy in multi-stage flash distillation

Abstract

A solar assisted multi-stage flash (MSF) distillation system is economically compared with a conventional energy MSF plant. Moreover, the economical and climatic conditions that make competitive the use of solar energy in MSF plants vs. conventional energy are analyzed. The design arrangement of the solar distillation system considered consists of a solar parabolic trough collector field coupled to a conventional MSF plant. The solar field directly heats the brine until its top temperature. Therefore, the solar field acts as brine heater when solar energy is available. Nevertheless, the plant consumes conventional energy at nighttime. The parameters analyzed are the climatic conditions, which define the energy production and the average daily operation time of the solar field; the capacity and the performance ratio of the desalination plant; the cost of the solar collector, and the cost of conventional energy. It was concluded that the solarassisted distillation system described above could make possible the competitiveness of the use of solar energy in MSF distillation plants.