Energy recovery devices for reverse osmosis applications

  • Overview
  • Product range
  • Documents
  • How it works

3-in-1 energy recovery device

The 3-in-1 Energy Recovery Device (ERD) optimized for sea water reverse osmosis applications. With iSave you get pressure exchanger, booster pump and motor integrated into one compact unit for high efficiency and short pay-back time.

The small footprint of iSave makes it a popular solution when the space is limited. When fitted with iSave, the Danfoss APP pumps produce more fresh water per square meter than any other system in the market.

iSave can be used in almost any SWRO application – land-based or marine, new or retrofit. The 3-in-1 design allows fast commissioning, continuous monitoring of performance and easy regulation to accommodate seasonal changes. Other isobaric devices have been known to cause over-spin and over-flushing that lead to poor process control and low efficiency. This is avoided with the active control possibilities offered by the iSave technology.

iSave captures hydraulic energy from the high pressure reject stream of the SWRO process and transfers the energy back into the system, drastically reducing the energy consumption regardless of flow rate and size of your SWRO system. Besides substantial energy savings, the iSave ERD also cuts capital expenditure by reducing high-pressure pump size, number of pipes and components thanks to its integrated design.

iSave ERD for reverse osmosis brochure cover featuring a city along a beach with a Danfoss ERD highlighted

Superior energy recovery in SWRO

Danfoss iSave is a patented, high-efficiency Energy Recovery Device (ERD) that guarantees constant membrane feed in SWRO applications of any size – on land, at sea or on the move.

Features and benefits

Extensive application know-how

Competitive efficiency rates

Compact – pressure exchanger, pump and motor in one unit

Easy and service-friendly design

Simple and reliable with high uptime

Short pay-back time

iSave selection tool by Danfoss app icon

iSave selection tool

Download the iSave selection tool for easy calculation and selection. Calculate amount and size of iSaves for your project.

Product range


Type Name Language Valid for Updated Download File type

How it works

Wherever simplicity and space matter, iSave’s 3-in-1 design makes energy recovery as easy as it is efficient.

iSave’s unique design puts three key components of isobaric energy recovery exactly where they belong: right next to each other. So now engineers can configure RO systems that are simpler, smaller and easier to operate – not least in tight places like containers.

When installed with compact APP high-pressure pumps, the Danfoss pump-and-ERD package produces more fresh water per square meter than any other system on the market.