Abstract :
When desalinating seawater using reverse osmosis membranes, the high-pressure pump consumes more than 70% of all energy used in the desalination plant. Ever increasing energy prices force the desalination industry to focus on overall power consumption of the high-pressure pump and the total Sea Water Reverse Osmosis (SWRO) plant. Since the introduction of Energy Recovering Devices (ERD) for large plants, energy consumption per m3 water produced has been reduced to such degree that nowadays it is possible to produce drinking water in large plants using less than 2kWh/m3. The manufacturers of ERD components have not focused on small plants producing up to 100 m3/day. Few technologies are available for small plants but despite considerable energy savings, these technologies are unprofitable. Development of the Danfoss high-pressure Axial Piston Pumps (APPs) has provided new attractive possibilities for reducing energy costs considerably while simplifying the plant setup at the same time. Danfoss’ mind-set comes from 45 years of product development within the oil hydraulic industry. This experience enables small plants producing as little as 0.2 m3/h to reduce their energy costs by more than 50 %.