Abstract. In this work a combined system consisting of a CPV and thermal (CPV-T) system connected with a reverse osmosis (RO) and membrane distillation (MD) for desalination is presented. In the CPV-T electrical energy is generated. The electrical energy is partly needed to run the desalination systems (e.g. pumps). The surplus electricity can be fed into the grid or an electrical storage system. The reverse osmosis process is the most energy efficient and established way of desalting brackish water and high volumes of pure water can be reached. However, with rising salinity the specific energy consumption (SEC) of RO rises significantly. Therefore, a second desalination system is introduced, the MD. The distillation is driven by the difference in temperature and vapor pressure of two fluid cycles. Hence, in the MD the thermal energy generated in the CPV-T system is used to heat the cycle of the high temperature side. The MD process runs with low temperature heat (<100 °C) and its SEC is less sensitive to the water salinity than the RO-process. Therefore MD is suitable to achieve high brine salinity by further concentrating the brine resulting from the RO-process. The connection in series of the both desalination technologies is especially useful to treat brackish water that is often found in high DNI regions, thus match to the CPV technology very well. The scarce water resources in dry regions are of high value and should therefore be as fully used as possible. In addition, the quantity of brine that needs to be disposed of is reduced when concentrating to a high salinity.

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