2020 Volume 30 Issue 3 Pages 35-42
For greening the desert, fresh water cost is required to be less than 50 ¥/m3 or less at the plantation site from the view point of economical productivity of greening. Under the condition of water transportation/distribution cost of 20-30 ¥/m3, desalination cost should be less than 30-20 ¥/m3. Furthermore, the energy sources and the cost of the electric power should be qualified for the production, transportation, and distribution of the huge amount of produced fresh water together with the treatment of salt-concentrated water.
In conclusion, the energy sources and cost for water production from deep seawater are qualified and reduced by the following system: Combination of rough NF/rough RO/TC is introduced and the concentrated water is used for salt production. Low-temperature solar-thermal-energy conversion is used as a stable, safe, low-cost, and environment-friendly power-generation system.
As a possible future energy-saving system, the absorption heat pump one is also proposed, although it is under the conceptual design level, at present.
