Nortek partners with ORPC and UNH to explore forward looking acoustic Doppler pProfilers for tidal turbine optimization and control.
Marine hydrokinetic devices use the force of the water to turn a turbine to create electricity. Precise measurements of the water speed and variability (turbulence intensity) may be used to control the turbine and optimize power generation. Accurate measurements of flow variability are important for structural analysis of the turbine. Better control of the turbine includes the ability to verify that the expected power generation is met for the present flow conditions (turbine is not blocked or damaged) or modulate rotation if the current exceeds a predetermined speed. Power generation may be optimized by detailed real-time measurements of the water speed and variability (caused by eddies, waves, etc). Further optimization may be possible if the water speed and variability may be observed some time in advance of actual interaction with the turbine and feed into a real-time feedback loop.
Measurement of the water speed and variability well upstream of the turbine are therefore necessary in order to observe the flow in advance of interaction with the turbine. To accomplish this goal, forward-looking Nortek Aquadopp Profilers have been mounted to an Ocean Renewable Power Company (ORPC) tidal turbine and a University of New Hampshire (UNH) test turbine in a variety of studies at R&D sites in Maine and New Hampshire. The Aquadopp Profilers were configured with a transducer geometry that provides two-component flow measurements (horizontal) and allows forward-looking (upstream) measurements to be made on both the flood and ebb tides using a single instrument. The profiles of along-beam velocity at a horizontal range of nominally 8 m (2 MHz) and 25 m (1 MHz) are described as related to mean flow, turbulence intensity, and predictive potential.
A summary of this work (PDF, 3 MB) was presented at the MREC 3rd Annual New England Marine Renewable Energy Center Technical Conference held in Boston in November 2011.
Nortek wishes to thank the support from ORPC (Bill Corbett & team) and UNH (Martin Wosnik & team).