Co-ordination Action for Autonomous Desalination Units ... - ADU-RES

distillation desalination processes, large sizes are more attractive due to the big
requirements of energy in small sizes.
Water
output
Potable
Distillate
Potable
Potable
Distillate
Potable
Distillate
Table 3 Recommended RES-Desalination combinations
Water
input
Brackish Water
Sea Water
System Size
Conventional Energy
+ RO, ED
Solar Distillation
PV - RO
PV - ED
Wind - RO
Wind - ED
Conventional Energy
+ RO, ED,
MSF, VC, MED
Solar Distillation
PV - RO
PV - ED
Wind - RO
Wind - ED
Wind - VC
Solar Thermal - MED
Solar Thermal - MSF
Geothermal - MED
Geothermal - MSF
Small Medium Large
(1-50 m3/d) (50-250 m3/d) (>250 m3/d)
WP2 ADU-RES 15
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
(CRES, 1998)
Additionally, desalination systems have traditionally been designed to operate with a
constant power input. Unpredictable and non-steady power input, force the
desalination plant to operate in non-optimal conditions and may cause operational
problems.
Energy cost is one of the most important elements in determining water costs where
the water is produced from desalination plants. Some energy consumption data for
traditional desalination plants using different desalination techniques are given
below. These data refer to conventional operated plants in operation at their nominal
power consumption and production [E. Tzen, R. Morris, 2003].
- for RO systems: 5-10 kWh/m 3 without energy recovery (large production plants),
2.5-4 kWh/m 3 with energy recovery
- for ED systems: 1.22 kWh/m 3 (for feed water salinity of 3000 ppm and product
salinity of 500 ppm TDS). This consumption is increased by the operation time:
increment of 50% after 2.5 operation years
- for VC systems: 8.5 - 16 kWh/m 3 , depending on size.