Work Exchangers (DWEER)

The Dual Work Exchange Energy Recovery (DWEER) is the most efficient energy recovery technology available today. No other technology achieves higher efficiency or lower plant operating costs.


The Calder DWEER is one of the most efficient energy recovery devices available today and is installed in many of the world’s largest RO plants. Able to recover up to 98% of the energy in the brine stream, it is a substantial improvement over alternative power recovery devices and technologies. The result is a significant reduction in an SWRO plant’s operating costs. And, with its unrivaled operational flexibility, robust design, high availability, extremely low maintenance costs and 25+ year service life, it will continue to keep operating costs low for decades.

Truly High Efficiency

Though some technologies claim comparable performance, the DWEER's very low mixing and leakage rates result in higher efficiency and lower plant operating costs. For a plant operating at flow rate of 190 000 m3/h, the difference means an additional savings of US $333 000 per year or an additional US $8 million savings for a typical 25 year BOOT project.

Of course every plant is different. To show how much money the DWEER can save after an installation Flowserve has developed a calculation program. It allows users to input data from competitor's published data sheets and compares this with the leakage and mixing numbers of the DWEER, the two main variables in calculating the efficiency of an Energy Recovery System. Download the DWEER calculation program to learn how much money you can save. 

High Operational Flexibility

The DWEER’s operational flexibility is unmatched and translates into extremely high availability and reliability. It is able to tolerate significant fluctuations in both system flow and pressure with no performance degradation or equipment damage. It can handle flows as low as 200 cubic meters per hour without vibration or pulsation simply by slowing the operating speed. This incredible adaptability permits smooth transitions in flow during start-up and shutdown and enables plants to easily accommodate normal fluctuations in demand.

The DWEER also tolerates foreign objects with ease. It can pass objects up to 50 microns without incurring damage so no special flushing procedures, strainers or filtration systems are needed.

Engineered to Last

The service life of the DWEER is designed to exceed 25 years. Its extremely low maintenance costs and high availability attest to its exceptional engineering and robust construction. Its slow operating speed, few moving parts and outstanding materials of construction are critical to its longevity and reliable performance.

The DWEER also provides several benefits in regards to the layout, design and operating environment of the reverse osmosis plant. All serve to keep construction costs and times low.

  • The DWEER uses a basic header design which simplifies engineering and construction.
  • The operation of the DWEER is not affected by its orientation or its location relative to the membranes. It can be configured in a train or in a center design, or beside or beneath the membranes. This versatility means the footprint of the DWEER and its associated piping runs are easily optimized to suit the design and size of the plant.
  • The DWEER generates less than 83 decibels so noise hoods or enclosures are not needed.

Low Maintenance Costs

To keep maintenance costs low, wear is limited to a few inexpensive and easily replaceable parts by design. Annual spare parts costs are typically less than one percent of the equipment cost. And, all tasks can be performed in the field and with standard tools.

Flowserve offers maintenance contracts that guarantee minimum efficiencies for key equipment including the DWEER. Contracts can be designed to suit specific needs and may include availability or power consumption guarantees.

Types of Flowserve Work Exchangers (DWEER)

Select a type of Work Exchangers (DWEER):