The effect of wind speed fluctuations on the performance of a wind-powered membrane system for brackish water desalination
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Date
2011Author
Park, Gavin L.
Schäfer, Andrea
Richards, Bryce S.
Metadata
Abstract
A wind-powered reverse osmosis membrane (wind-membrane) system without energy
storage was tested using synthetic brackish water (2750 and 5500 mg/L NaCl) over a range
of simulated wind speeds under both steady-state and fluctuating conditions. The parameters
varied were: i) average wind speed from 3.7 (system start-up) to 8.7 m/s; ii) wind turbulence
intensity from 0.0 (steady-state conditions) to 0.6 (extreme fluctuations); and iii) period of
oscillation from 15 to 90 s. With a feed water of 2750 mg/L NaCl, the wind-membrane system
produced good-quality permeate (<600 mg/L) over the full range of wind speeds and
fluctuations. The system performance (in terms of permeate flux and NaCl concentration) at
average wind speeds of 7.0 m/s or more was unaffected by fluctuations up to a turbulence
intensity of 0.4 and was independent of the period of fluctuation within this operating range.
With a feed water of 5500 mg/L NaCl an average wind speed of 7.0 m/s or more was required
to produce adequate-quality permeate (<1000 mg/L) under fluctuating conditions. It is
concluded that this wind-membrane system can be operated within a safe operating window
with large power fluctuations, but further control strategies are required to deal with
intermittent operation, especially with higher salinity feed waters.