Powering reversible actuators using forward osmosis membranes : feasibility study and modeling

The aim was to determine the impact of membrane properties and operating conditions upon predicted performance of osmotically driven actuators. An actuator fitted with a forward osmosis membrane was studied, and significantly we examined the reversibility of the actuation process. It was discovered that the actuation-retraction cycle could be repeated for over 60 cycles before salt concentration became similar on both sides of the membrane. The cycle length and number of operative cycles were shown to be a dependent on membrane properties. It was demonstrated that issue of long actuation time can be addressed using membranes with high water permeability.