Several factors affect the amount of fresh water produced by a watermaker. These include feed water salinity, temperature, membrane age and pressure.
A change in salinity or temperature can lead to over-production and damage the membranes if the driving pressure is not adjusted.
Salinity: Many believe that salinity levels are the same across the globe. This is not the case. The map below shows the differences in salinity levels worldwide. Furthermore many vessels routinely enter lakes or bays where salinity levels can change drastically.
Temperature: Membrane productivity is very sensitive to changes in water temperature. As the feed water temperature increases the volume of fresh water produced increases.
Pressure: RO systems use pumps to pressurize the seawater in order to perform the reverse osmosis process. Most systems include a valve that is adjusted manually to control the freshwater production rate with varying salinity and temperature. As membranes age they become fouled and require higher driving pressures to produce the same quantity of water.
Automatic Regulation: Bluecube watermakers have an optional patent pending system that automatically varies the driving pressure to maintain the systems designed product water flow rates. This system takes into account the salinity, temperature and membrane fouling among other factors and automatically sets the exact pressure required. As a failsafe the system can also be operated in manual mode.
