Renewable-energy consultancy, Natural Power, has demonstrating matched performance of its continuous wave wind lidar, ZephIR, to a calibrated wind tunnel.
The lidar unit measures wind speed and characteristics from ground level to 200 m. It was deployed in LM Windpower’s wind tunnel in Denmark and successfully measured wind speeds from 5 to 75 m/s with an averaged difference of just 0.4% for a sustained period of time and across all measured speeds. To the company’s knowledge, these are the first reported tests in the world to accurately measure the performance of a lidar in a wind tunnel and help demonstrate ZephIR’s ability to measure low and high wind speeds for wind-resource assessments in the renewable energy sector.
These test results feed in to the DNATF project ‘Integration of Wind LIDAR’s in Wind Turbines for Improved Productivity and Control’. They also demonstrate the performance of a sister product of ZephIR 300 called ControlZephIR which is based on a ZephIR but with different system software and mechanical housing allowing the unit to be either spinner or nacelle mounted. ControlZephIR provides wind-turbine controls with necessary data from a number of distances in front of the turbine. This data that lets the turbine steer in to the wind to maximise performance but, more importantly, steer out of the wind safely in high gusts or turbulence aimed at reducing through-life costs of a wind turbine generator due to operations & maintenance downtime.
The LM Wind Power wind tunnel is a closed circuit wind tunnel with a closed test section with flow driven by a 1-MW fan. A flow speed of up 105 m/s can be reached and the good flow quality is achieved with aerodynamically treated corner vanes, a honeycomb structure, three screens, and a nozzle with a contraction ratio of 10 to 1. The 7-m test section has a cross section of 1.35-m wide and 2.7-m high.
The effort is part of a Danish National Advanced Technology Foundation (DNATF) project combined with Denmark’s National Laboratory for Sustainable Energy, Risø DTU, turbine-blade manufacturer LM Wind Power, and optical and laser solutions provider, NKT Photonics.
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