Danfoss has introduced two reverse osmosis energy recovery devices.
The iSave 21 with a brine flow of 7-21 m3/h and the iSave 40 with a brine flow of 22-40 m3/h are available now. More sizes are under development.
The Danfoss iSave consists of an isobaric pressure exchanger (PE), a high pressure positive displacement booster pump (BP) and an electric motor.
The isobaric pressure exchangers are based on the technology used in the Danfoss APP pumps, and the high-pressure booster pumps are based on the vane pump principle enabling a very light and compact design. The design of iSave 21-40 ensures lubrication of the moving parts by the fluid itself.
All parts included in the iSave 21-40 are designed to provide long service life with a constant high efficiency and minimum service required.
The vane pumps are fixed displacement pumps in which the flow is proportional to the number of revolutions of the driving shaft – enabling flow control.
The electric motor provides speed control of both the pressure exchanger and the high pressure booster pump on the same shaft – preventing over spin / over flushing.
The iSaves need a VFD that allows the motor to apply a constant torque from low speed to maximum speed.
For the complete range of Danfoss iSave Devices go to our dedicated website: High Pressure Water Equipment - iSave Devices
| Operating Conditions | ||
| iSave 21 | iSave 40 | |
|---|---|---|
| Code number | 180F7000 (US 180F7010) | 180F7001 (US 180F7011)180F7003 |
| Energy Recovery Device | iSave 21 | iSave 40 |
| Rated flow | 21 m3/hr | 41.4 m3/hr *1 |
| Geometric displacement | 265.8 cm3/rpm(16.2 in3/rpm) | 626 cm3/rpm(38.2 in3/rpm) |
| High-pressure inlet flow, maximum | 21 m3/hr (92.4 gpm) | 44 m3/hr (194 gpm) |
| Low-pressure inlet flow, maximum | 33 m3/hr (145 gpm) | 67 m3/hr (295 gpm) |
| High-pressure inlet pressure,maximum | 83 bar (1200 psig) | 83 bar (1200 psig) |
| High-pressure inlet pressure,minimum | 10 bar (145 psig) | 10 bar (145 psig) |
| High-pressure inlet pressure,intermittent, minimum *3 | 3 bar (43.5 psig) *2 | 3 bar (43.5 psig) |
| Low-pressure inlet pressure, maximum *3 | 10 bar (145 psig) | 10 bar (145 psig) |
| Low-pressure outlet pressure,minimum | 1 bar (14.5 psig) | 1 bar (14.5 psig) |
| High-pressure outlet pressure,maximum | 83 bar (1,200 psig) | 83 bar (1,200 psig) |
| Filtration requirements (nominal) *4 | 3 ìm melt-blown | 3 ìm melt-blown |
| Torque, maximum *5 | 36 Nm (26.5 lbf-ft) | 119 Nm (87.8 lbf-ft) |
| Starting torque (slip/stick) | - | 85 Nm (62.7 lbf) |
| Power req. at 60 bar, and booster pressure of 3 bar | 5.5 kW (7.5 hp) | 10 kW (15 hp) |
| Weight including electric motor | 95 kg (209,5 lb) | 254 kg (560 lb) |
| Performance | ||
| iSave 21 | iSave 40 | |
| Peak eff. inc. high-pressure booster pump at 60 bar | 93% | 91% |
| Maximum pressure raise on iSave *7 | 3 bar (43.5 psig) | 5 bar (72.5 psig) |
| Maximum low-pressure differential(LP In - LP Out) *7 | 0.9 bar (13 psi) at 21m3/hr(92.4 gpm) | 1.2 bar (17.5 psi) at 40 m3/hr(176.1 gpm) |
| Maximum lubrication flow at 60 bar | 0.42 m3/hr (1.8 gpm) | 0.8 m3/hr (3.5 gpm) |
| Minimum speed | 500 rpm | 600 rpm |
| Maximum speed | 1,500 rpm | 1,200 rpm |
| Salinity increase at membrane at 40% recovery rate | 2-3 % | 2-3 % |
| Typical noise level *6 | 86 dB(A) | 88 dB(A) |
| *1 Typical average flow at 60 bar | ||
| *2 Minimum inlet high pressure can be 1 bar, if speed of iSave is maximum 750 rpm | ||
| *3 Intermittent pressure is acceptable for less than 10 minutes within a period of 6 hours | ||
| *4 Please see section 7 of datasheet - Filtration | ||
| *5 Warning: A minimum of 10 seconds is required when ramping up the speed from zero to maximum. Otherwise, the torque will exceed the maximum limit and may be harmful to the isave. | ||
| *6 Noise level is depending on system design. The noise level can be obtained by “proper” design. Please contact M & M Controls. | ||
| *7 At speed above 50Hz and power supply lover than 400V the maximum pressure raise is 4 bar. | ||
| Electric Motor | ||
| Description | iSave 21 | iSave 40 |
| Motor size kW/HP | 5.5/7.5 | 11/15 |
| Frame size | IEC 132S-4P | IEC 160L-6P |
| Speed at 50/60 Hz | 1440/1728 | 970/1165 |
| Efficiency | 89% | 90% |
| Rated current (A) | 10.7 | 22 |
| Insulation according to DIN-IEC 34 | Class F | Class F |
| Ambient temperature 40oC, 1000m above sea level | Class B | Class B |
| Degrees of protection | IP55 | IP55 |
| Standard coating according to IEC 60721-2-1 | Yes Yes | Yes |
| The iSave can also be delivered with a marine motor, an ATEX motor or any other special motor. | ||
| Please contact M & M Controls for further information. | ||
