The SWPE energy recovery unit consists of an APP pump and an APM motor, both connected to a double shafted electric motor. Energy recovery is obtained when high-pressure brine from the membranes is fed to the APM that converts the energy in the pressurized brine to mechanical energy to be re-used by the electric motor. As the APM has a fixed volumetric displacement, the recovery rate will be fixed.

APP pumps and APM motors are designed to supply low viscosity and corrosive fluids under high pressure, eg. in seawater reverse osmosis filtration applications and for high pressure salt water pumping. The pumps and motors are based on the axial piston principle enabling a very light and compact design, and they are designed so that lubrication of the moving parts in the pumps and motors is provided by the fluid itself. No oil lubrication is thus required. All parts included in the pumps and motors are designed to provide long service life, i.e. long service life with a constantly high efficiency and minimum of service required.

The pumps and motors are fixed displacement units in which the flow is proportional to the number of revolutions of the input shaft and the pump/motor displacement, regardsless of any counter-pressure. The electric motors are designed for driving equipment that requires continuous operation, and their high efficiency reduces energy consumption.