Submersible Load Cells Lower the Cost of Large Tidal Turbine Designs

AIM – Assess the Performance of Alternative Large Scale Tidal Turbine Designs

One of the costlier items in current large >15m diameter tidal turbine designs are the rotor blades.

Lowering the cost of rotor blade manufacture would make this renewable energy more economical to use and widely accessible.  Plus, benefiting not only the UK tidal energy markets but developing tidal energy countries too.

The EPICTidal Team consisting of Lab-Sea-Systems Dr Florent Trarieux, Cranfield University’s Dr Joao Amaral-Teixeira and Nick Barlow, Managing Director of Designcraft Ltd (UK-based blade design and manufacturer) wanted to know the performance implications of employing lower cost methods for the manufacture of large scale tidal turbine rotors.

SOLUTION – Applied Measurements DDEN Submersible Load Cells

To assess the rotor blade performance the EPICTidal team developed a submersible tidal turbine test rig incorporating 2 of Applied Measurements DDEN load cells.

“The DDEN load cells were ideal to use in this application as they are fully submersible up to 10 metres” explains Bob Davies, Applied Measurements’ Production Director.

The rotor blade design to be tested was coupled to the tidal turbine test rig and placed in a state-of-the-art test tank.  Here the team were able to increase the size, flow rate and turbulence levels within the tank.  The first DDEN load cell measured the torque and the second measured the thrust of the tidal rotor design.

Applied Measurements DDEN in-line submersible load cells are low profile, very compact and designed to measure both tension and compression underwater.  They come with an IP68 rating and are sealed using ‘O’ rings to guarantee integrity during long term submersion.  Their IP68 rating and ‘O’ ring sealing make them ideal to use underwater or in areas at risk of flooding.

They come in capacities from 0-250N up to 0-50kN with customised capacities, threads and dimensions on request.  As well as versions rated to greater submersion depths in seawater, oil and other more aggressive media.

For this submersible application, the DDEN load cells were fitted with 10 metres of submersible 4-core screened polyurethane cable for complete submersible protection underwater.  They have a guaranteed accuracy to <±0.15% of the rated capacity (0.05% typical) enabling precise thrust and torque blade measurements which was crucial to this renewable energy application.

DDEN Submersible Load Cell Outputs

A small ICA6H amplifier was fitted within the bodies of both DDEN submersible load cells. This delivered a high-level ±10Vdc analogue output, for use with their data acquisition and control systems. Thanks to its 19mm diameter, the ICA6H was easily fitted within the body of the DDEN submersible load cells, maintaining the submersible protection needed for underwater testing.

Other outputs are available for the DDEN including 0-5Vdc, 0-10Vdc or 4-20mA, which can be used with many data acquisition and control systems.  For a digital output, a DCell load cell digitiser can be used instead of an ICA to deliver an RS485 digital output.

Discuss your application with us

If you have a torque application you would like to discuss, please contact Applied Measurements on (+44) 0118 981 7339 or visit

We have over 25 years of transducer experience and offer a range of load cells, force sensors, level & depth sensors, pressure sensors, torque and displacement transducers.  Our products are used in a broad range of industries from geotechnical to aerospace, to subsea and R & D. We can also provide a full customisation service from minor modification to the full design, development and manufacture of a completely bespoke product.

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