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3. Water Resource Development
(1) Solar desalination system
A new concept of Solar desalination system is under planning to develop a sustainable desalination system by natural energy. This system operates Reverse Osmosis (RO) and Multi Effect Desalination (MED) with steam energy generated by solar heat collector. Similar system with this concept for electric power generation has been operated for more than 20 years in California. Maximum amount of power generation is 380MW and its production cost of electric power is about 5 cent/kWh.
Fig. 7 Flow diagram of solar desalination system

(2) Moisture collector with air conditioner
Moisture collection volume is so small with conventional air conditioners, because they cool down the re-circulating air inside a house. We improved an air conditioner as moisture collection system, as shown in Fig. 8. We calculated a water collection rate under the actual meteorological condition observed in Abha. It can be seen from Fig. 9 that the water collection rate much depends on the relative humidity of each month. If the cooling temperature will be maintained to be low, we can obtain a water by more than 50 litter/day.
Fig. 8	Air conditioner with moisture collection system, where collected water can be seen in right hand side	Fig. 9	Calculated results of production rate of water at Abha, where Qs is air volume supplied and ET cooling temperature