The Danfoss iSave 70 (code 180F7025) is a complete seawater reverse-osmosis energy recovery unit supplied on a horizontal base frame with a IEC 200 L 18.5 kW (30 HP), 6-pole motor. It combines a rotary pressure exchanger and a booster pump in one assembly, recovering pressure energy from the membrane reject stream and returning it to the feed — typically cutting SWRO energy consumption by around 60% against a system with no energy recovery.
Documentation & Drawings
Technical Specifications
| This Configuration | |
| Code number | 180F7025 |
| Model | iSave 70 — horizontal base frame |
| Motor | IEC 200 L, 18.5 kW (30 HP), 6-pole |
| Efficiency at max. speed, 60 barg (871 psig) | 92.4% |
| Alternative orientation | 180F7040 (vertical) |
| Performance | |
| Flow at min. speed, HP out | 50 m³/h (220 gpm) |
| Flow at max. speed, HP out | 70 m³/h (308 gpm) |
| Max. allowable working flow, LP in | 70 m³/h (308 gpm) |
| Peak flow, LP in | 120 m³/h (528 gpm) |
| Max. lubrication flow at 60 barg (871 psig) | 25 l/min (6.6 gpm) |
| Speed range | 625 – 875 rpm |
| Max. pressure HP out (MAWP) | 83 barg (1200 psig) |
| Min. pressure HP out | 40 barg (580 psig) |
| Max. differential pressure (HP out − HP in) | 5 barg (72 psig) |
| Min. pressure HP in, intermittent | 2 barg (29 psig) |
| Max. pressure LP in (MAWP) | 5 barg (72 psig) |
| Max. pressure LP in, peak | 10 barg (145 psig) |
| Min. allowable working pressure LP in | 2 barg (29 psig) |
| Differential pressure at max. flow (LP in − LP out) | 0.79 barg (11.46 psig) |
| Max. static test pressure (HP in / HP out) | 108 barg (1566 psig) |
| Max. static test pressure (LP in / LP out) | 13 barg (189 psig) |
| Max. allowable working torque | 190 Nm (140 lbf-ft) |
| Max. starting torque (stick/slip) | 180 Nm (132 lbf-ft) |
| Operating Conditions | |
| Media temperature | 2 – 35°C (36 – 95°F) |
| Ambient temperature | 0 – 50°C (32 – 122°F) |
| Filtration requirement (nominal) | 5 micron melt-blown |
| Salinity increase at membrane (40% recovery) | 2 – 3% |
| Sound pressure level LPA at 1 m | 86 dB(A) |
| Motor | |
| Motor size | 18.5 kW (30 HP) |
| Frame size | IEC 200 L |
| Poles | 6 |
| Nominal speed | 985 rpm |
| Rated current | 37 A at 400 V |
| Rated motor torque at nominal speed | 177 Nm (130.5 lbf-ft) |
| Motor ambient temperature, max. | 40°C (104°F) |
| Motor insulation class | B |
| Motor degrees of protection | IP 55 |
| Weight & Footprint | |
| Weight (dry) | 463 kg (1,021 lb) |
| Weight (operation with water) | 471 kg (1,038 lb) |
| Footprint (horizontal) | 0.76 m² (8.14 ft²) |
| Identification | |
| Manufacturer | Danfoss High Pressure Pumps |
| Data sheet reference | Danfoss AI264763692435en-000904, §8.4 |
Videos
Optimizing SWRO energy use with Danfoss pumps and iSave ERD selection tools
Understanding SWRO energy use — how to cut it with Danfoss pumps and ERDs
Videos courtesy of Danfoss High Pressure Pumps.
Case Studies
Real installations using Danfoss pumps and iSave energy recovery:
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How the iSave Works
The iSave combines a rotary pressure exchanger, which transfers pressure energy directly from the high-pressure reject brine to the incoming low-pressure feed, with a booster pump that makes up the small pressure differential across the exchanger, both driven by the motor on a common shaft. Because the energy transfer is direct hydraulic displacement rather than a mechanical conversion, the high-pressure feed pump only has to supply the permeate flow.
The iSave 70 delivers up to 70 m³/h (308 gpm) at the high-pressure outlet. All wetted parts are made of high corrosion-resistant materials including Super Duplex stainless steel, and there is no high-pressure mechanical seal and no need for high-pressure flow meters.
Frequently Asked Questions
How do I size the iSave 70 for my plant?
What is the difference between 180F7025 and 180F7040?
What pre-filtration does it need?
Does it need a separate booster pump?
Does it need a VFD?
How is it shipped?
Specifications reproduced from Danfoss data sheet AI264763692435en-000904. iSave® is a registered trademark of Danfoss A/S. Danfoss reserves the right to alter specifications without notice; confirm critical values against the current data sheet before purchase.
