iSave energy recovery device

The Danfoss iSave energy recovery device delivers a fully integrated 3-in-1 solution that combines an isobaric rotary pressure exchanger, high-pressure booster pump, and electric motor within a single compact unit. Through advanced isobaric technology paired with intelligent speed control, iSave maximizes seawater treatment efficiency while recovering up to 92% of hydraulic pressure from concentrated water discharge streams. Engineered with premium corrosion-resistant materials (Duplex/Super Duplex, PEEK), this compact, flexible design streamlines installation and operation for demanding seawater reverse osmosis applications.

Brand: Danfoss

Product Type: Energy recovery devices

PRODUCT FEATURES

Integrated 3-in-1 design: Combines high-pressure booster pump, isobaric rotary pressure exchanger, and electric motor in a single optimized unit
Universal SWRO system compatibility: Engineered for stationary and mobile water treatment systems, onshore and offshore applications
Concentrated water pressure recovery: Delivers up to 60% energy reduction versus non-ERD systems, dramatically cutting operational expenditures
Simple automated operation: Features simplified operation with integrated VFD speed control
Superior corrosion resistance: Duplex/Super Duplex stainless steel and PEEK construction ensure exceptional durability and maintenance simplicity
Pressure-independent performance: Maintains consistent flow rates through positive displacement technology, even under variable pressure conditions
Extended operating cycles: Engineered for minimum 2-year maintenance-free operation with high reliability
System simplification: Eliminates high-pressure flow meter requirements, reducing both capital investment and operational complexity
Field-serviceable design: Enables straightforward maintenance without extensive system disassembly
Certified performance: Supplied with Type 3.1 performance certificates compliant with EN 10204 standards

SPECIFICATIONS

HP outlet flow range at max. differential pressure (for iSave 21 - 40)

6 – 41 m³/h (26 – 180.5 gpm)
Flow at min. speed, HP out (for iSave 50 - 70)

42 – 50 m³/h (184 – 220 gpm)
Flow at max. speed. HP out (for iSave 50 - 70)

52 – 70 m³/h (228 – 308 gpm)
HP max. outlet pressure

83 bar (1,200 psi)
LP inlet max. pressure

5 bar (72 psi)
Differential pressure HP in - HP out max.

5 bar (72 psi)
LP differential LP in - out at HP max. flow

0.53 – 1.2 bar (7.69 – 17.5 psi)
Speed

500 – 1,500 rpm

The Danfoss iSave energy recovery device sets the benchmark for energy recovery efficiency in seawater RO applications, delivering an optimal balance of design innovation, operational reliability, and capital investment return. This comprehensive analysis explores iSave’s technical capabilities and application advantages across diverse desalination environments.

1. Technical specifications of iSave energy recovery device

Understanding technical specifications is crucial when selecting an optimal iSave energy recovery device in seawater RO applications. Comprehensive specification data enables precise system design and performance optimization for specific project requirements.

iSave without motor:

SPECIFICATION	VALUE
SPECIFICATION	iSave 21 Plus	iSave 40	iSave 50	iSave 70
Geometric displacement	273 cm³/rev (16.7 In³/rev)	626 cm³/rev (38.2 In³/rev)	–	–
PRESSURE
Differential pressure HP in – HP out max.	5 bar (72.5 psi)
HP max. outlet pressure	83 bar (1,200 psi)
Min. pressure HP out	–	–	40 bar (580 psi)
HP min. inlet pressure	15 bar (217 psi)	20 bar (290 psi)	–	–
HP max. inlet pressure	83 bar (1,200 psi)		–	–
HP inlet min. pressure, intermittent	3 bar (44 psi)		2 bar (29 psi)
LP inlet max. pressure	5 bar (72 psi)
LP inlet max. pressure intermittent	10 bar (145 psi)		–	–
Max. pressure LP in, peak	–	–	10 bar (145 psi)
LP outlet min. pressure	1 bar (14.5 psi)		–	–
Min. allowable working pressure LP in	–	–	2 bar (29 psi)
Differential pressure at max. flow (LP in – LP out)	0.9 bar (13 psi)	1.2 bar (17.5 psi)	0.53 bar (7.69 psi)	0.79 bar (11.46 psi)
Max. static test pressure (HP in and HP out)	–	–	108 bar (1,566 psi)
Max. static test pressure (LP in and LP out)	–	–	13 bar (189 psi)
SPEED
Min. speed	500 rpm	600 rpm	525 rpm	625 rpm
Max. speed	1.500 rpm	1.200 rpm	650 rpm	875 rpm
TYPICAL FLOW
HP outlet flow range at max. differential pressure	6 – 22 m³/h (26 – 96 gpm)	21 – 41 m³/h (92 – 180.5 gpm)	–	–
Flow at min. speed, HP out	–	–	42 m³/h (184 gpm)	50 m³/h (220 gpm)
Flow at max. speed. HP out	–	–	52 m³/h (228 gpm)	70 m³/h (308 gpm)
Max. lubrication flow at 60 barg (871 psig)	0.4 m³/h (1.8 gpm)	0.8 m³/h (3.5 gpm)	25 m³/h (6.6 gpm)
LP inlet max. flow	33 m³/h (145 gpm)	67 m³/h (295 gpm)	–	–
Peak flow, LP in	–	–	120 m³/h (528 gpm)
Max. allowable working flow, LP in	–	–	57.2 m³/h (252 gpm)	70 m³/h (308 gpm)
TORQUE
Torque at max. differential pressure operation	49 Nm (36 lbf-ft)	102 Nm (75 lbf-ft)	170 Nm (125 lbf-ft)	190 Nm (140 lbf-ft)
Max. starting torque (stick/slip)	50 Nm (37 lbf-ft)	150 Nm (110 lbf-ft)	180 Nm (132 lbf-ft)
TEMPERATURE
Media temperature	2-40°C (36-122°F)		2-35°C (36-95°F)
Ambient temperature	0-50°C (32-104°F)		0-50°C (32-122°F)
Filtration requirements (nominal)	5 micron melt-blown 85% efficient		5 micron melt-blown
Salinity increase at membrane at 40% recovery rate	2-3%
Weight	47 kg (103 lb)	123 kg (271 lb)	164 kg (362 lb)

iSave with IEC motor:

SPECIFICATION	VALUE
SPECIFICATION	iSave 21 Plus (Model 180F7016)	iSave 21 Plus (Model 180F7017)	iSave 40 (Model 180F7001)	iSave 40 (Model 180F7004)	iSave 50	iSave 70
Motor size IEC version IEC 400 V, 50 Hz	5.5 kW (7.5 HP)	7.5 kW (10 HP)	11 kW (15 HP)	15 kW (20 HP)	–	–
Frame size	IEC 132 S (4 pole)	IEC 132 M (4 pole)	IEC 160 L (6 pole)	IEC 180 L (6 pole)	IEC 200 L (6 pole)	IEC 200 L (6 pole)
MOTOR DATA
Nominal speed	1,450 rpm		970 rpm		985 rpm
Min. speed at 400 V	500 rpm		600 rpm		–	–
Max. speed at 400 V	1,500 rpm		1,100 rpm	1,200 rpm	–	–
Rated current at 400 V	11 A	15.2 A	22 A	30 A	37 A
TORQUE
Motor torque at nominal speed	36 Nm (26,5 lbf-ft)	49 Nm (36 lbf-ft)	108 Nm (80 lbf-ft)	146 Nm (107,7 lbf-ft)	170 Nm (125 lbf-ft)	177 Nm (130,5 lbf-ft)
Motor torque at min. speed	27 Nm (20 lbf-ft)	36 Nm (27 lbf-ft)	95 Nm (70 lbf-ft)	129 Nm (95 lbf-ft)	180 Nm (132 lbf-ft)
TEMPERATURE
Motor ambient temperature, max.	40°C (122°F)				2-35°C (36-95°F)
Filtration requirements (nominal)	–	–	–	–	5 micron melt-blown
Motor insulation	Class B
Motor degrees of protection	IP55
Sound pressure level max.	78 dB(A)	79 dB(A)	84 dB(A)		83 dB(A)	86 dB(A)
Weight	105 kg (231 lb)	116 kg (255 lb)	254 kg (560 lb)	305 kg (672 lb)	441 / 463 kg (972 / 1,021 lb)
FOOTPRINT (VERTICAL / HORIZONTAL)
Vertical	0.31 m² (3.34 foot²)	0.32 m² (3.45 foot²)	0.5 m² (5.38 foot²)	0.54 m² (5.81 foot²)	0.44 m² (4.71 foot²)
Horizontal	0.31 m² (3.34 foot²)	0.32 m² (3.45 foot²)	0.16 m² (1.72 foot²)	0.17 m² (1.83 foot²)	0.76 m² (8.14 foot²)

iSave with NEMA motor:

SPECIFICATION	VALUE
SPECIFICATION	iSave 21 Plus (Model 180U0013)	iSave 21 Plus (Model 180U0052)	iSave 40	iSave 50	iSave 70
Motor size NEMA version, high efficiency 460 V, 60 Hz	7.5 kW (10 HP)	11 kW (25 HP)	15 kW (20 HP)	–	–
Frame size	NEMA 215 TC (4 pole)	NEMA 254 (4 pole)	NEMA 286 TC (6 pole)	–	–
MOTOR DATA
Nominal speed	1,760 rpm	1,765 rpm	1,175 rpm	1,180 rpm
Min. speed continuous at 400 V	500 rpm		600 rpm	–	–
Max. speed continuous at 400 V	1,500 rpm		1,200 rpm	–	–
Motor rated current 460 V	12.4 A	18 A	24.2 A	36.2 A
TORQUE
Motor torque at nominal speed	40 Nm (29.4 lbf-ft)	59.7 Nm (44 lbf-ft)	119 Nm (88.2 lbf-ft)	170 Nm (125 lbf-ft)	177 Nm (130.5 lbf-ft)
Motor torque at min. speed	20 Nm (14.7 lbf-ft)	31 Nm (23 lbf-ft)	95 Nm (70 lbf-ft)	180 Nm (132 lbf-ft)
TEMPERATURE
Motor ambient temperature, max. 3,300 feet above sea level	40°C (122°F)			–	–
Motor degrees of protection	IP55			–	–
Sound pressure level max.	78 dB(A)	79 dB(A)	84 dB(A)	83 dB(A)	86 dB(A)
Weight	152 kg (335 lb)	206 kg (454 lb)	324 kg (715 lb)	484 / 506 kg (1,067 / 1,116 lb)
FOOTPRINT (VERTICAL / HORIZONTAL)
Vertical	0.38 m² (4.09 foot²)	0.45 m² (4.85 foot²)	0.65 m² (7.0 foot²)	0.44 m² (4.71 foot²)
Horizontal	0.38 m² (4.09 foot²)	0.16 m² (1.72 foot²)	0.23 m² (2.48 foot²)	0.76 m² (8.14 foot²)

2. Advantages of iSave energy recovery device – Danfoss

Energy recovery technology is critical in modern seawater RO system economics, directly impacting operational efficiency and capital investment returns. The iSave device excels in modern desalination applications through these key advantages:

Significant energy savings: Up to 60% reduction in energy consumption, substantially lowering operational costs
Space-efficient design: Compact 3-in-1 configuration minimizes installation footprint
Reduced auxiliary costs: Eliminates high-pressure flow meter requirements, reducing system complexity
Smaller HP pump requirements: Reduces high-pressure pump sizing, lowering system investment costs
Extended maintenance intervals: Minimum 2-year service intervals reduce operational disruption
Premium materials: Duplex/Super Duplex and PEEK construction ensure extended lifespan and superior corrosion resistance
Certified performance: Type 3.1 performance certificates per EN 10204 standard validate reliable operation

3. iSave energy recovery device certifications

Performance validation through recognized certification standards demonstrates product reliability across demanding marine and industrial applications. The Danfoss iSave ERD maintains EN 10204 Type 3.1 performance certification, confirming adherence to stringent international performance and safety standards for critical water treatment applications.

4. iSave energy recovery device applications

iSave devices serve diverse seawater RO applications where performance reliability, operational efficiency, and lifecycle economics drive system selection criteria:

Modular desalination systems: Containerized and skid-mounted solutions for hospitality, residential, and commercial facilities in coastal and island locations
Marine and offshore applications: Shipboard and platform-based water treatment systems for vessels, yachts, and offshore industrial operations
Industrial desalination: Oil and gas, mining, and manufacturing operations requiring reliable freshwater production in remote locations
Municipal water infrastructure: Public utilities, regional authorities, and private water companies implementing large-scale desalination projects

5. Authorized iSave energy recovery device distribution

Strategic distributor selection ensures optimal iSave energy recovery device performance, maximizes operational efficiency, and extends equipment service life through proper technical support and genuine parts availability. ATS Water Technology Co., Ltd. maintains official Danfoss distributor status in Vietnam, delivering comprehensive iSave solutions with full technical backing.

Partnership with ATS Water Technology guarantees authentic products supported by complete documentation, including certificates of origin (CO), certificates of quality (CQ), technical documentation, and international certifications. Our technical services encompass comprehensive solution engineering, technology consultation, and equipment optimization tailored to specific RO system parameters and operational requirements.

With proven expertise in water treatment technology and a specialized technical team, ATS Water Technology Co., Ltd. delivers trusted partnership for SWRO projects requiring iSave energy recovery device integration. Contact our technical specialists today for detailed engineering consultation and customized solution development.

ATS WATER TECHNOLOGY CO., LTD