The integration of Multi Effect Desalination (MED) unit with and without Thermal Vapor Compression (TVC) system into the Linear Fresnel Rankine Cycle (LFRC) was investigated for different seawater temperatures when it is located at the regions with different solar radiation levels. A comparison was made between the fresh water costs of the dual purpose LFRC/MED (or LFRC/MED/TVC) plants and the case when the MED and MED/TVC systems use direct steam of the LF solar field to produce fresh water (LF/MED & LF/MED/TVC). The water production costs of the described dual purpose plants were compared with that of the LFRC/Reverse Osmosis (RO) plant (LFRC/RO). An exergo-economic analysis was performed to determine the water unit costs of the plants. The results show that the fresh water costs of the 1.3/MED and LF/MED/TVC configurations are higher than that of the dual purpose plants. Also, it was shown that the fresh water cost is more affected by solar radiation level rather than seawater temperature of a region. It was also found that at fuel prices of 0.23$/m(3), the water production costs of fuel based dual purpose plants would be equal to that of the plants with solar thermal source.